+Dave Hilts Greetings, Dave. It's good to hear from you. Yes, Jack must have his daily 10-hour nap or else he's too tired to stay up all night running around the house, making noise. Rusty, on the other hand, prefers to sleep all night.....and all day :)
Don't you love those step bits? I just bought a set a few months ago, they're great for re-sizing grommet holes on the radio chassis! I loved that "one eye open" look of disdain Jack gave you upon waking him up from his nap!
+Tim Dockery Amen, Tim. Step bits are the greatest thing since flush toilets. I was hoping the barely open eye would be evident in the video.....utterly disdainful, but cute as heck :)
This is some of the best tutorial video I have ever seen. There's no extended unnecessary chatter, the information is clear, content is relevant and useful, and steps are well defined. I am just thrilled. I will be watching for all the new stuff as it's released. Thanks so much for an exemplary job.
Thanks so much, Paul. You have hit upon one of my prime goals.....to avoid mindless chatter and just get to the point, in brief sentences that each contain at least one vital point.....or bit of humor :) I'm flattered that you like our channel, and welcome you to all our videos.
Uncle Doug, one of my first amp builds was a Fender Champ style amp build fitted inside a 1936 Philco radio art deco cabinet, I found in the attic of my mother-in-laws house on Lake geneva, WI. My brother-in-law was kind enough to let me use his GREENLEE chassis punch kit for the tube holes. The kit had the pheumatic hand pump. Worked like a charm.
+Eric Reicher Greetings, Eric. That sounds like a great project, and it eliminates the need to construct and cover a cabinet (tough jobs). I've seen Greenlee punches, but never owned or used them. Perhaps I can find a set at a yard sale or on Craigslist in my area. Thanks for your input :)
Hey Uncle Doug & Rusty, I hope your all doing good, nice to get some rain I bet. Awesome construction techniques and a fine looking job! I'd put my money on home made any day. I really am enjoying the series and looking forward to next one. I do appreciate you sharing all your years of experience so as others might benefit from it, Thankyou. Take care, be good, Cass.
As always, very enjoyable. Always look forward to your videos. Rainstorms in Texas are majestic things to watch, eclipsed only by the progress on an Uncle Doug build. :)
I just did another AO-35 video. I know you're not much of a hard rock guy, but you should check out the demo at the very end! I don't know if yours came out this way, but this one is a fire-breathing monster! I can't believe this thing is from the 1950s. Can't wait for your next installment, by the way! Your cabinet work is exceptional. There isn't a production amp today made to the standard you're putting in here. You could sell these for big buck if you wanted to, Doug.
Thanks so much, Brad. I respect your judgement and really appreciate your kind appraisal. Hopefully, when the day comes to sell my creations, your value prediction will come true :) Re the AO-35, yes indeed, they are quite impressive. Much more powerful than the AO-44, and capable of some serious mayhem. I'll check out your video.
Very exciting ! this gets better every time. Rusty is probably going to want to review his contract after this build, he is a lot more involved. he will probably want cookies per screen time... Thank you so much for this build !
+scott entrekin You're welcome, Scott. When it comes to wrangling cookies, Rusty is a master. Every time I enter the garage on the way into the house, he sneaks in with me and won't leave until he gets a cookie.....and this happens about 10 times a day. What a clever scoundrel :))
Uncle Doug, I just wanted to let you know how much I'm enjoying the series. You are really doing a fabulous job laying out everything out and making it so understandable, I can't wait to take this and build my own amp. Please understand that I have the ultimate respect for you but I want to hear how it's going to sound before I totally commit to my own build... (Ha, ha, ha...) :-). You are the best, just a joke, thanks for everything you do! Buddy
+Buddy Martin I don't blame you, Buddy. It may end up looking great but sounding awful.....but I sincerely hope not :) No matter what, it can be tuned up to sound wonderful. Thanks for your kind words.....glad you're enjoying the series.
Really enjoying this series Doug and the quality of the build throughout. The finger jointing is a great way of jointing, i more often than not see butt joints and screws and strengthened with blocks even in commercial project. Thanks for showing us how to do it the right way. Take care and all the best to Rusty and Jack. Colin
+mixolydian2010 Thanks, Colin. Yes indeed, box joints are really strong and require no metal fasteners to interfere with the routering. I have no doubt I could stand on the cabinet, along with Rusty and Jack, and it wouldn't waver a bit.....but I'm not going to test my theory :)
Hello again Uncle Doug, Rusty and Jack. It seems I never get enough of your detailed videos (as always) of the way things should be done, not the way they may be done. A new blade is important, as cutting some wood products (especially that grained particle board) causes sparks to come out when sawing against the carbide teeth of the 10 inch table saw blades. Wears out the sharpness of the carbide teeth very quickly. I see you got the the traditional 3/4 inch good grained pine. That's good as it is important for cabinet resonance and many amp manufacturers use pine because of that. I have a 40 year old sabre saw, that has those blades that can bite you, but for cutting out some funny shapes or metal it still has it uses. I have pretty much have all the woodworking tools/saws/bandsaws and a myriad of clamps of different shapes and sizes. I see that Jack your cat, only gets into the action when he wants some attention. As you know, cats don't do woodwork or any other kind of work for that matter. LOL! Nice work on the wood cabinet especially with those all important box finger joints. The bull nosed edges of the cabinet make it very attractive looking. Those step bits take a powerful drill press to drive it. Very nice transformer layout. Go to to see the use of rubber grommets, not every commercial amp uses these. Solid looking 16 guage chassis..how much do you estimate it weighs without any components added yet. Looks very heavy to me.
+SuperCarver2011 Thanks so much for your detailed and favorable analysis, SC. I would guess that the chassis weighs around 4 lbs. I was somewhat apprehensive about the difficulty of machining it, but everything went quite well. I tried to stress the importance of proper lubrication to expedite the drilling process and preserve the drill bits. I fear that many people simply try to force the bit through the metal with no lubrication at all.....not a good idea.
+Uncle Doug Yes, I have broken many small bits by forcing the bits through metal on a drill press (especially aluminum) causing the bit to bind up and twist off, leaving me having to buy another one to finish the job. Same situation with hacksaw blades when you just go at it without some lubrication on the metal blade
Okay, I do realize the video is quite old by today's "tech standards" according to the laws of popularity in the what's new category. However, I'm now 48, and just decided as part of my retirement under military disability, that I seriously needed another hobby, so I decided to follow through with my dream of learning to play guitar, which I've started now, for the 3rd time. But I've found the construction of my own tube amplifier to be a viable hobby build in it's own right, this is amazing the hell out of me..! Thank you for such a complete and detailed video..!
I was wondering why there had been a pause between this and the last video. My you have been a busy bloke!! It's a pity you live all the way across the pond on the edge of the desert. I could really do with spending some time picking your brains over a beer or a coke/soda. If only my garage was as tidy and well kitted out. Keep it going Uncle Doug!!
+Andy Wragg Thanks, Andy. Yes, everyone was getting impatient, but there was a lot of work to do to prepare for this episode. The next one will be even worse. All the point-to-point wiring is quite time consuming. If you ever do make it out this way, let us know and Rusty and I will join you for a beer :)
Hi Uncle Doug! Maan that timber cabinet looks like it was made by a cabinetmaker in a woodshop! Very professional looking! Those finger-jointed corners look magnificent mate! Flawless & strong as all get out! Great idea bolting the speaker centre-hole & using your router to cut it! Unfortunately, I didn't have a router table to make the 15 inch cutout in the baffle for my 'Silicon Chip' magazine Majestic speakers that I built. I just had to use a jigsaw, unfortunately. After I cut out the hole (which was naturally quite rough!), I smeared a small amount of black boot polish around the edge of the timber disk that I had cut out & screwed a 4 inch length of 1 x 1 inch cleat into the disk centre hole as a handle. Then I rotated the disk inside the hole to mark the high points in the speaker cut-out, then sanded the high points down with sandpaper wrapped around a piece of dowel. I repeated this process until there were no high points left. The process worked really well, & I glued up & painted the internal edges of the speaker cut-out with wood glue & primer. I managed to source some real nice 10-32 T-nuts for each of the 8 blackened allan-key head mounting bolts, which I 'siliconed' & hammered in for a perfect airtight seal. The speakers are rated at 300W RMS @12.5Hz - 20kHz so I had to be sure there were no air leaks, & there were none! Yay! Your metal chassis looks fantastic mate, & I especially like your idea of an internal steel wall to keep power supply noises out of the preamp circuitry! I hope you kept your furry friends out of the workshop while you were drilling all the chassis holes, with all that razor sharp metal swarf getting flung about! I guess all the racket you must have made would have deterred them a bit ay? A totally wonderful, professional job mate, with just one possible problem. I was a bit worried when I saw that you used a rocker switch for the 6L6/6V6 selector, which may get accidentally bumped. I dunno, but I would have used a slide switch that fits behind the panel & requires a screwdriver to move it, like mains voltage selector switches that I have seen. Maybe it's not such a problem, but may run 6V6's too hot if in the 6L6 position? You've probably already thought of that scenario, but anyway that's the only worry I have for your amp my friend! Other than that, it's a 12/10!
No, it´s like loosing a familymember, as a friend said about he´s dog "He is like a human" that´s pretty true i guess, at least seen to how much one miss them.
Uncle Doug, this video/documenting is really quite a fine service. The amount of work & energy required to record everything, explain as you go, wrangle your pets, and maintain enough breath to repeat the cycle is nothing short of miraculous. The fact that you have so much of this information (and experience) in your memory and guts is special. Thanks again, It's Saturday night, I wanted to watch a movie, instead I've played my guitar, and learned about "Scratch-Building..." one hell of an amp. My condolences for the loss of such a good old friend. I haven't been able to keep an animal since losing my childhood companion...It just hurt too much (my loss, I know ). B :)
Thanks so much, Brad. Nice comments like yours make it all worthwhile :) Yes, indeed, loving animals comes with a price..... but generally the rewards outweigh the final cost.
As an added comment, I use my Stihl (Al Gore approved) gas leaf blower to clean out my table saw, router table and sander in the backyard. Works like a champ. It is even better for cleaning out my Ford F-150 interior. I start her up, open the windows, turn on the air (high) and blast the interior. Way easier than vacumming. My wife thought I was crazy until I demonstrated the advantages of the leaf blower.
+Eric Reicher I like the leaf blower idea, Eric. I just use my air compressor to blow off the tools and work area. Rusty hates it and hides, but it works pretty well.....and I'm sure old Al would approve :))
So very interesting, you sir are a true perfectionist and craftsman, not too many people are talented as you are. Well done and thanks for your videos.
Very impressive. It almost makes me want to build my own chassises. You explain it very well. You were an instructor in your former life? I think Rusty should renegotiate his contract. He is becoming quite a celebrity.
+Steve Dewitt Thanks so much, Steve. Yes, I was a math and science teacher for almost 20 years. Don't tell Rusty, his agent is already squeezing me for a raise and perks as it is :)
Hi Uncle Doug: Another great video. I honestly find you do the most thorough and informative videos. Using them as a guide, I will be able to take my amp building level to a whole new height. I am glad you are doing a Supro design, because I was thinking of building one earlier, (I'm a Jimmy Page fan), but I couldn't find the proper info on how to do it. I eagerly await the next part. thanks again, Bob
+starlingave Thanks so much, Bob. It's great to hear that the video series is helpful. Thanks for watching, and best of luck with your Supro project :)
+wreckoningday Thanks, WD. Rusty wrote the script for that scene and played his part quite well. His pay was two cookies, so he ended up doing very well indeed :)
HEY UNCLE DOUG I Like the way you explained everything on your videos. Nice and easy. Waiting for part 7 an the rest of your serie NICE WORK en thanks for all your great videos. Greetings Hans ( Holland ) and for Rusty and Jack a hug.
What you might want to consider is what I did for the Magnaclone: get a scrap piece of wood and use wood screws to mount the terminal strips to it (lay out the terminal strips with the same measurements they'll be in the chassis.) This lets you wire up almost everything, without having to work inside the chassis. Once you've got the terminal strips wired up, you can transfer them to the chassis, screw them in (or rivet, in your case), and then just run wires to the tube sockets, pots and transformers. I got my terminal strips laid out in the chassis the same way you did, then drilled their mounting holes. Then I stuck a board under the chassis and marked through the holes with a Sharpie. Then I just used some short wood screws to hold the terminal strips to the board while I soldered the components on.
Hello Doug Really coming together great. Seems Jack and Rusty have traded places.:) Enjoyed and looking forward to your next video in this series. All the best. Bobby
Uncle Doug I am really enjoying this series and will hate to see it end. Red is my favorite color. I hope sometime you do a video of building a cabinet with red Tolex. I know you have already picked the color and will like whatever you pick. Well I am rambling Lol. All the best Doug. Bobby
Good news, Bobby. I just got home from the vinyl store and red is one of the colors I selected.....partially due to the bright red covering on the original Supro in Part 1.
Hey Doug, another great series. While I completely understand your choice of chassis material, I will point out of couple of things for followers who may not be familiar with hot-rolled sheet steel, which is what you used. That "blueing" is actually mill scale from the hot-rolling process and it's a lousy conducter (makes poor grounds but a GREAT capacitor, though). That stuff fiercely resists TIG welding unless you've scrupulously ground away the mill scale and cleaned the weld surfaces with alcohol or other appropriate cleaner. Additionally, if you live in a moist climate such as Middle Tennessee (Nashville) where gulf air is constantly streaming up this way, that steel is going to start rusting five minutes after you drill the first hole. Then, you're left with the option of painting (after grinding away the mill scale as paint won't stick to it) or throwing it away and selecting a more suitable chassis material. Please understand this is not a criticism of your choice of material. For just a few bucks, on the other hand, a metal distributor will sell you aluminum (or steel) "drops" for a fraction of the price of a sheet. An excellent choice might be a 5052 alum, for example, in .040 thickness. Easy to bend, MUCH easier on those expensive step drills, etc. And lastly, speaking of drilling, oil products never make good coolant for drilling as they lube the material instead of cooling it, which is the last thing you want. It LOOKS like you're drilling when you're actually rubbing your way through it. The MOST effective, and least expensive cutting fluid that I've ever used for drilling is a 50/50 mixture of Pine-Sol and tap water. Just my $.02.
Wow, thanks for the very informative input, Bruce. I have used aluminum for chassis in the past and found it easy to work, but difficult to bend without getting stress cracks. Most of the steel I use does not have mill scale, and with our 6 to 8% humidity, rust is not a big issue.....but I fully understand that it's a real problem in many parts of the world. I have been using a special cutting and threading fluid, but will definitely try your Pine-Sol recipe. Again, thanks so much for sharing this info with us :)
There are actually two reasons that stress cracks develop in aluminum during bending: 1) the heat treat of the material, e.g., T3, T4, or T6 doesn't lend itself to working and 2) your bend radius is too tight for the thickness. For small amp chassis of the size we're dealing with here, 2024, 3004, 5052, or 6061, CONDITION O (pron "oh") alloys in .032 thickness would be PLENTY strong enough and EASILY cut, drilled, and bent. Using the bending process you demonstrated here would work perfectly on a piece of 2024-0, .032 and be fully as strong as that safe you built from the HR piece of steel. Please forgive for the crack about the "safe" - that appeared at the doorstep of my tongue and I was powerless to keep it from just tumbling on out there. Best wishes.
I never cease to be amazed by the wealth of information available from viewers. I am taking some notes regarding the alloys you recommend, and will do some experimenting in the future. Thanks again :)
Excellent again. Very good advice regarding the output transformer being off-axis from the power transformer! I didn't know that. Also, you aren't there yet, but reverb pan orientation is important. You don't want the output transducer/pickup of the reverb pan to be at the same end of the cab as the power transformer or it could pick up noise from the transformer.
+tremelo68 Thanks so much, Trem68. You're absolutely correct about the output transducer being as far as possible from the PT. Over the years, I have observed the hum that can occur if it isn't. It's probably one of the main causes of reverb hum problems. Hopefully, the Supro will be totally hum-free :))
Another great one, Doug...and since i bought myself a router years ago, i always use it, makes things a *lot* more easier, just as you shown in here as well...:) :)
Really makes one appreciate just how labor-intensive it is to build an amp from design and construction, to finished product. I can`t imagine how one would put a price on the blood, sweat, and dog biscuits and still call it an affordable amp once its all said and done. I know its not an amp you intend to sell really, but more of a personal endeavor and a hobby for your own enjoyment. Lastly, and it shouldn't be a huge concern as I wouldn't think there are any nefarious characters lurking in our midst, however, you may want to blur out your license plate of your Jeep just to be sure. There is a tool in editing that provides that `blur-out faces` feature. I`m sure it would work for license plates just the same. All the best good sir, and looking forward to the final chapter in this series. Cheers!
+Krang Gangs You're right about labor-intensive, Lee. Each time I build one of these, I am reminded just how much work is involved. I can see why mass-produced cabinets (in foreign lands with low wages), printed circuit boards, and robot assemblers all came into being. Re the license plate, it was an oversight and probably can't be remedied once the video is posted. I guess if anyone wants to drive all the way down here to face Rusty's fangs, claymore mines, barbed wire, and five clips of .45 ACP to steal an old Jeep and some homemade amps, then there is just no stopping them :)) Thanks for your concern.
Really nice work; the perfection of all the rounded edges is amazing and the cabinet looks gorgeous. I must congratulate you on some of the original idea's to bring this project to the point that I now see. "Incredible"
Really impressed . All my amps have had the transformers on the other side and the input section on the opposite side also so struggling to get my head round a "mirror image " amp. Also I've built from plans and turret boards . so tag strips will be a new challenge .
use a drilling lubricant! Brilliant! Having just done this a few times DIY, it never would have occurred to me, but it makes perfect sense. I was a bit surprised that you used porcelain tube sockets. My preference is to use those dirt brown Belkins. I often will design my amp's faceplates on my laptop, and lay it out real nice and have that made before I drill the chassis. That way I can get it to conform to the faceplate perfectly. It helps that I have some background in graphic design.
+Alva Goldbook Yes, by all means use a proper lubricant, Alva.....and not WD40 or some silicon spray. I use a special machinist's lube that is specified for drilling and tapping. It makes the difference between a 3-second drilling time and a 3-minute (smoking, bit-destroying) drilling time. Your faceplate idea sounds great. I hope mine turns out nearly as well :)
+Uncle Doug I get my faceplates made for around $35 each. It ends up being pricey this way. One of these days I'll set up my own silk screening station, but this is how I do it for now. Here's the faceplate graphic I designed for that rebuild of my Fender Hot Rod Deville into a blackface type amp I was talking about earlier. The spacing of the holes are based upon the existing chassis. i.imgur.com/1PjRAZQ.png
Hey Uncle Doug, how about a nice clear lacquer finish. I really like the look of a pine cabinet with a clear finish. Your covered cabinets are beautiful as well :)
You think rain is fun...hmmmm,come live in scotland for a week,that'll cure the love of rain. Seriously,love the vids,even though it's been 4yrs,tubes are still timeless,what is it you guys say "keep on truckin'|".
Beautiful.... ..Nicely & Artfully Done.....(Milling is always the way to go if you can do it). Good tip on the transformer placements...changing the angle of attack to a right angle on the magnetic fields...so that it may might be less likely for the fields to interfere with each other ....very good . The Devil is always in the details.....excellent ! ;D) B.
+Uncle Doug and Rusty......Actually I was referring to your use of the Router table to "Mill" out your speaker baffle opening....."wood milling".....I should have been more specific.... but now that you mentioned it.....wouldn't be wonderful to have one of my old "Bridgeports" setting in the garage to take on those pesky metal cutting/ milling chores.... Hah!! ......Cheers...Bill
Bridgeport mills are wonderful, until it's time to move one :P I have a small mill, but only use it for tasks that can't be done in any other manner, due to the required set-up and clean-up time.
It was like I was looking over your shoulder! Are you going to make or order the dash/faceplate? Man that is a great idea to install terminal strips. It will cut back a little on over all weight and be so easy to wire to. Brilliant! Your production crew seems a little bored. I guess they can't wait to smell the completed amp. Thankz
+Audio Tech Labs You're welcome, ATL. I will make my own nameplate, as described in one of my videos. Glad you like the terminal strips. Usually, two parallel rows, almost full length, will do the job. I may have to add a couple as the wiring progresses.
Uncle Doug, to think I have been doing it with a sabre saw for eons. I have a router table in the garage and never thought of using it. I award myself the DUMMY of the century award. LOL.
hey......a contracts a contract. coming out incredible. nicely turned that nice piece of cold rolled into swiss cheese. I've got a nice set of greenlee KO punches thattle come in handy for this. off to favorites.........
+R HEIDEMAN Thanks, RH.....glad you liked the swiss cheese :) Rusty has a good stout bark, but when he's begging for a cookie, his voice shifts to become almost a cough. I have no idea why. Maybe he's just being polite :)
+Arnold Rimmer Thanks, Arnold. I am tempted to build a bare wood cabinet, but would want to use a more attractive wood than pine.....perhaps mahogany or (expensive) walnut.
thanks for the tip . as far as the carpet tape I found a better way regular masking tape and super glue . put the masking tape on the template and the workpiece then a thin bead of super glue holds much better . cost much less and is much thinner. I use that to make inserts for my saws . to cut out vents in back panels any number of things. thanks again
+MrMac5150 You must be a fan of "Things to do in Denver when you're Dead", Mr. M......one of my favorite shows. Let's hope we're never on the receiving end of a "Buckwheat" :)
If I was a manufacturer, I'd approach you for your prototype... but my question was, did you consider plating the chassis? ...and though I know the cab will be really boss (or 'dope' or 'bomb' as the youngsters say nowadays) with the covering, I can't help but wonder how she would've looked with a natural or a sunburst finish... But no matter as I know it'll be smokin' in the end (;-b) Oh and also, I'm so glad you hinted at the possibility of using a 6L6 or a 7027 or 6550 for those times when a bit more power might be desirable... Really enjoying this series. thanx and... cheers
Excellent Uncle Doug !! While watching and listening to you handle the 16 GA chassis - it sounded so very solid - I was wondering how much it weighed !! I noted your earlier comment that perhaps 18 GA would have been adequate. Any conjecture as to how much lighter that would be ? Thanks for all the great videos !!!
+Donald Filbert It probably weighs 3 or 4 lbs, Don. I would think in 18 gauge it would be about 20% lighter. It is really solid, but machined up without any problems. You're welcome for the videos. Glad you enjoy them :)
If the main filter capacitors at the power nodes are rated At 500 to 525 volts DC you could run a 5AR4 when running the 6L6 and then the 5Y3 when running the 6V6 even with the 2 position bias switch That way both the 6V6and6L6 can have two power settings each.
We're all enjoying this build immensely! Doug, what gauge is the sheet metal of your chassis? I'm making a new front panel for my variac and I'm wondering what gauge metal those step bits will go thru. I'm pretty sure what I currently have is 15 ga. Needs to be fairly heavy to hold the variac mechanism. Thanks again for the great videos!!
+headinsouth1 You're welcome, HS. I used 16 gauge for the chassis, which is about .060" thick.....very stout. The step bits didn't have much trouble enlarging the holes, especially when properly lubricated.
I was wondering how you’d upholster the cutaway for the controls.I’m sure you’ve noticed that Fender and vox have an upside down“V” cut with a strip under it in the corners. I wonder why they don’t just do the controls the same way as the oval cuts on the back of amps.
It has to do with the radius of the curve and the thickness of the wood being covered, William. The rear panels are much thinner than the top panel and the covering material can be stretched without cutting.
Hi Doug! Do the rubber grommets serve a function other than protecting the wires from sharp edges? Do they prevent inductance or something? I just noticed that my amp doesn't have them. Thanks! ...and as always - great video!
+HungryFreaksDaddy You're welcome, HF. As far as I know, it's just to prevent chafing and possible short circuits. Lots of amps don't have them.....but to be honest, they probably should. I always feel safer with them. If you don't have them, you could wind some electrical tape around the wires where they pass through the chassis wall.
+Alva Goldbook It's a Vermont American brand, Alva, possibly defunct by now. I bought it at least 40 years ago. It's solid steel, unlike the "modern" ones which are probably plastic.
how well did cutting out the hole for the speaker work when you routed the last bit of it . I am very interested. I build cabinets every day I have tried several ways and have thought about doing it like that but figured at the very last inch it would cause problems . I use templates I originally made by bolting a speaker to ply and using a flush trim bit the bearing riding on the speaker basket or more correctly the foam or cardboard gasket. but from many uses the templates wear out mostly from putting the studs through them
+Jim Lundin Make a template out of 3/4 inch plywood. Spray it with several coats of polyurethane. Use double stick carpet tape to hold it in place while you cut with a template router bit. ( bearing on top) if you don't spray the template the tape will peal the wood out in chunks after lots of use.
+Jim Lundin It worked perfectly, Jim, all the way around. I too was worried that once the center circle was freed from the baffle, the baffle might wander and get chewed up.....but there was no problem at all. I was using a straight-sided, unpiloted bit and maintained good control over the baffle at the end.
Hello Doug, do you intend to spray the outer of the chassis. I think you live in a rather dry climate area so moisture and rust on the steel may not pose a problem. Here in NZ we get 4 seasons in one day, so I would think spring or powder coat would be ideal. You do need bare metal for the grounding though don't you, especially the ground bus if there is one???
+allanpennington You bring up a good point, Allan. It's very tempting to either paint or clearcoat the entire chassis, both for appearance and rust prevention, but then you create grounding issues, so it's kind of an enigma. I'll come up with a solution.....I hope :)
+Uncle Doug was going to ask about this myself. paint is important but so is proper grounding. what if you rivet all the holes (and keep them hollow) , mask them out and paint the rest of the chassis?
Believe me, I'm trying to come up with a practical approach, Szymon. Other than using stainless steel for the chassis, any ferrous metal presents this same problem.
I have a question Uncle Doug if you can get around to it. I have watched your videos many times, and i mean a lot. I understand so much now about tube amps, but one thing still puzzles me. On a fixed negative bias, many amps will have two 220k grid leak resistors to the bias. Wouldn't this drop the bias voltage almost to zero at the grid? Or is the grid leak resistor calculated in having a higher negative voltage accounting for the 220k drop before the grids? That is the only thing that confuses me. Thanks! You have taught me a lot.
You are assuming that high value resistors will substantially reduce voltage, Joshua, but in reality, the voltage drop is based on current flow. Thus, if virtually no current is flowing, a 1 Meg Ohm resistor might not cause much voltage drop at all......while in a high current line, a 10 Ohm resistor might create a significant drop. In bias lines there is virtually no current.....where would it go? The grid is essentially a dead end.
Uncle Doug - do you believe there is any advantage using aluminium for a chassis? I’ve heard it reduces magnetic interference and could make for less hum. What’s your opinion? Thanks
I've used both it and steel many times and find no EMF benefits, but it's easier to machine than steel, weighs less, absorbs and transfers heat quite well, and won't rust. On the downside, you can't easily solder to it.
this is really getting good, Rusty is really coming out of his shell but I think Jack could be suffering from an identity crisis!
+Dave Hilts Greetings, Dave. It's good to hear from you. Yes, Jack must have his daily 10-hour nap or else he's too tired to stay up all night running around the house, making noise. Rusty, on the other hand, prefers to sleep all night.....and all day :)
you're craftmanship is impressive
Thanks so much, Mark :)
Don't you love those step bits? I just bought a set a few months ago, they're great for re-sizing grommet holes on the radio chassis! I loved that "one eye open" look of disdain Jack gave you upon waking him up from his nap!
+Tim Dockery Amen, Tim. Step bits are the greatest thing since flush toilets. I was hoping the barely open eye would be evident in the video.....utterly disdainful, but cute as heck :)
Rusty seems excited about the build, Jack must be waiting for the music....a hep cat. :)) Beautiful work, as always.
+bullthrush Thanks, Andrew. They're both actors. In reality they are both tireless helpers :)
This is some of the best tutorial video I have ever seen. There's no extended unnecessary chatter, the information is clear, content is relevant and useful, and steps are well defined. I am just thrilled. I will be watching for all the new stuff as it's released. Thanks so much for an exemplary job.
Thanks so much, Paul. You have hit upon one of my prime goals.....to avoid mindless chatter and just get to the point, in brief sentences that each contain at least one vital point.....or bit of humor :) I'm flattered that you like our channel, and welcome you to all our videos.
@@UncleDoug You do a great job of it, Doug. It really is refreshing amongst the UA-cam chatter.
@@MattHoyle1 Thanks, Matt :)
Uncle Doug, one of my first amp builds was a Fender Champ style amp build fitted inside a 1936 Philco radio art deco cabinet, I found in the attic of my mother-in-laws house on Lake geneva, WI. My brother-in-law was kind enough to let me use his GREENLEE chassis punch kit for the tube holes. The kit had the pheumatic hand pump. Worked like a charm.
+Eric Reicher Greetings, Eric. That sounds like a great project, and it eliminates the need to construct and cover a cabinet (tough jobs). I've seen Greenlee punches, but never owned or used them. Perhaps I can find a set at a yard sale or on Craigslist in my area. Thanks for your input :)
Hey Uncle Doug & Rusty, I hope your all doing good, nice to get some rain I bet. Awesome construction techniques and a fine looking job! I'd put my money on home made any day. I really am enjoying the series and looking forward to next one. I do appreciate you sharing all your years of experience so as others might benefit from it, Thankyou. Take care, be good, Cass.
+Cass Virgillo You're welcome, Cass, and thanks for the very kind words. We're glad you're enjoying the amp-building series :)
Uncle Doug You're the best! With this series, who needs Netflix? Lol!
+jesuspn03846 Thanks, Jesus. You make a good point. Ever since I started this series, I haven't had time to watch Netflix (or eat or sleep) either :))
I have watched most of your videos and never responded. Just wanted to say thanks for all you do and say hi to Rusty, Jack, and the parakeets!
+jcoakleyjr You're welcome, LC. It's great to hear from you. I'll relay your feelings to the menagerie......thanks for watching :)
As always, very enjoyable. Always look forward to your videos. Rainstorms in Texas are majestic things to watch, eclipsed only by the progress on an Uncle Doug build. :)
+Brad Linzy (The Guitologist) Thanks. You are too kind, Brad.....but I happily accept :)))
I just did another AO-35 video. I know you're not much of a hard rock guy, but you should check out the demo at the very end! I don't know if yours came out this way, but this one is a fire-breathing monster! I can't believe this thing is from the 1950s.
Can't wait for your next installment, by the way! Your cabinet work is exceptional. There isn't a production amp today made to the standard you're putting in here. You could sell these for big buck if you wanted to, Doug.
Thanks so much, Brad. I respect your judgement and really appreciate your kind appraisal. Hopefully, when the day comes to sell my creations, your value prediction will come true :) Re the AO-35, yes indeed, they are quite impressive. Much more powerful than the AO-44, and capable of some serious mayhem. I'll check out your video.
Very exciting ! this gets better every time. Rusty is probably going to want to review his contract after this build, he is a lot more involved. he will probably want cookies per screen time...
Thank you so much for this build !
+scott entrekin You're welcome, Scott. When it comes to wrangling cookies, Rusty is a master. Every time I enter the garage on the way into the house, he sneaks in with me and won't leave until he gets a cookie.....and this happens about 10 times a day. What a clever scoundrel :))
Wow! Finger joints, I'm impressed. If I do finger joints I may leave some of my fingers around the shop floor. You really do very nice work.
Thanks, Bob.
Uncle Doug, I just wanted to let you know how much I'm enjoying the series. You are really doing a fabulous job laying out everything out and making it so understandable, I can't wait to take this and build my own amp. Please understand that I have the ultimate respect for you but I want to hear how it's going to sound before I totally commit to my own build... (Ha, ha, ha...) :-). You are the best, just a joke, thanks for everything you do! Buddy
+Buddy Martin I don't blame you, Buddy. It may end up looking great but sounding awful.....but I sincerely hope not :) No matter what, it can be tuned up to sound wonderful. Thanks for your kind words.....glad you're enjoying the series.
the speaker cut on the router is ingenious!
Thanks. The method really works well :)
Really enjoying this series Doug and the quality of the build throughout. The finger jointing is a great way of jointing, i more often than not see butt joints and screws and strengthened with blocks even in commercial project. Thanks for showing us how to do it the right way. Take care and all the best to Rusty and Jack. Colin
+mixolydian2010 Thanks, Colin. Yes indeed, box joints are really strong and require no metal fasteners to interfere with the routering. I have no doubt I could stand on the cabinet, along with Rusty and Jack, and it wouldn't waver a bit.....but I'm not going to test my theory :)
Hello again Uncle Doug, Rusty and Jack.
It seems I never get enough of your detailed videos (as always) of the way things should be done, not the way they may be done.
A new blade is important, as cutting some wood products (especially that grained particle board)
causes sparks to come out when sawing against the carbide teeth of the 10 inch table saw blades. Wears out the sharpness of the carbide teeth very quickly. I see you got the the traditional 3/4 inch good grained pine. That's good as it is important for cabinet resonance and many amp manufacturers use pine because of that.
I have a 40 year old sabre saw, that has those blades that can bite you, but for cutting out some funny shapes or metal it still
has it uses. I have pretty much have all the woodworking tools/saws/bandsaws and a myriad of clamps of different shapes and sizes.
I see that Jack your cat, only gets into the action when he wants some attention. As you know, cats don't do woodwork or any other kind of work for that matter. LOL!
Nice work on the wood cabinet especially with those all important box finger joints. The bull nosed edges of the cabinet make it very attractive looking.
Those step bits take a powerful drill press to drive it. Very nice transformer layout. Go to to see the use of rubber grommets,
not every commercial amp uses these. Solid looking 16 guage chassis..how much do you estimate it weighs without any components added yet. Looks very heavy to me.
+SuperCarver2011 Thanks so much for your detailed and favorable analysis, SC. I would guess that the chassis weighs around 4 lbs. I was somewhat apprehensive about the difficulty of machining it, but everything went quite well. I tried to stress the importance of proper lubrication to expedite the drilling process and preserve the drill bits. I fear that many people simply try to force the bit through the metal with no lubrication at all.....not a good idea.
+Uncle Doug Yes, I have broken many small bits by forcing the bits through metal on a drill press (especially aluminum) causing the bit to bind up and twist off, leaving me having to buy another one to finish the job.
Same situation with hacksaw blades when you just go at it without some lubrication on the metal blade
Okay, I do realize the video is quite old by today's "tech standards" according to the laws of popularity in the what's new category.
However, I'm now 48, and just decided as part of my retirement under military disability, that I seriously needed another hobby, so I decided to follow through with my dream of learning to play guitar, which I've started now, for the 3rd time.
But I've found the construction of my own tube amplifier to be a viable hobby build in it's own right, this is amazing the hell out of me..!
Thank you for such a complete and detailed video..!
You're welcome, CA. Best of luck with your project :)
I was wondering why there had been a pause between this and the last video. My you have been a busy bloke!! It's a pity you live all the way across the pond on the edge of the desert. I could really do with spending some time picking your brains over a beer or a coke/soda. If only my garage was as tidy and well kitted out. Keep it going Uncle Doug!!
+Andy Wragg Thanks, Andy. Yes, everyone was getting impatient, but there was a lot of work to do to prepare for this episode. The next one will be even worse. All the point-to-point wiring is quite time consuming. If you ever do make it out this way, let us know and Rusty and I will join you for a beer :)
Hi Uncle Doug! Maan that timber cabinet looks like it was made by a cabinetmaker in a woodshop! Very professional looking! Those finger-jointed corners look magnificent mate! Flawless & strong as all get out! Great idea bolting the speaker centre-hole & using your router to cut it! Unfortunately, I didn't have a router table to make the 15 inch cutout in the baffle for my 'Silicon Chip' magazine Majestic speakers that I built.
I just had to use a jigsaw, unfortunately. After I cut out the hole (which was naturally quite rough!), I smeared a small amount of black boot polish around the edge of the timber disk that I had cut out & screwed a 4 inch length of 1 x 1 inch cleat into the disk centre hole as a handle. Then I rotated the disk inside the hole to mark the high points in the speaker cut-out, then sanded the high points down with sandpaper wrapped around a piece of dowel.
I repeated this process until there were no high points left. The process worked really well, & I glued up & painted the internal edges of the speaker cut-out with wood glue & primer. I managed to source some real nice 10-32 T-nuts for each of the 8 blackened allan-key head mounting bolts, which I 'siliconed' & hammered in for a perfect airtight seal. The speakers are rated at 300W RMS @12.5Hz - 20kHz so I had to be sure there were no air leaks, & there were none! Yay!
Your metal chassis looks fantastic mate, & I especially like your idea of an internal steel wall to keep power supply noises out of the preamp circuitry! I hope you kept your furry friends out of the workshop while you were drilling all the chassis holes, with all that razor sharp metal swarf getting flung about! I guess all the racket you must have made would have deterred them a bit ay?
A totally wonderful, professional job mate, with just one possible problem. I was a bit worried when I saw that you used a rocker switch for the 6L6/6V6 selector, which may get accidentally bumped. I dunno, but I would have used a slide switch that fits behind the panel & requires a screwdriver to move it, like mains voltage selector switches that I have seen. Maybe it's not such a problem, but may run 6V6's too hot if in the 6L6 position? You've probably already thought of that scenario, but anyway that's the only worry I have for your amp my friend! Other than that, it's a 12/10!
Thanks so much for your detailed analysis, Neville.
UD I would just like to add my praise too. This video series is sizing up very nicely. Meticulous. I'm now back in Blighty and no excuses
+robfpool Thanks so much, Rob. Give it a try......hopefully, you'll be very pleased and surprised (in a good way :) by the result.
Rusty is Cute, i miss my dog a bit when i see him.
Thank You for taking Your time uploading all those great videos!
You're welcome, SE. We miss Rusty now also.....he passed away a few months ago :(
I am sorry for him. I know how it feels, we will all remember him.
Thanks, SE. Losing a loyal friend is never a pleasant experience.
No, it´s like loosing a familymember, as a friend said about he´s dog "He is like a human" that´s pretty true i guess, at least seen to how much one miss them.
Yes, indeed.
Enjoying every step of this!
+Greg's Garage That's good news, Greg. Thanks for watching.
Uncle Doug, this video/documenting is really quite a fine service. The amount of work & energy required to record everything, explain as you go, wrangle your pets, and maintain enough breath to repeat the cycle is nothing short of miraculous. The fact that you have so much of this information (and experience) in your memory and guts is special. Thanks again, It's Saturday night, I wanted to watch a movie, instead I've played my guitar, and learned about "Scratch-Building..." one hell of an amp. My condolences for the loss of such a good old friend. I haven't been able to keep an animal since losing my childhood companion...It just hurt too much (my loss, I know ). B :)
Thanks so much, Brad. Nice comments like yours make it all worthwhile :) Yes, indeed, loving animals comes with a price..... but generally the rewards outweigh the final cost.
As an added comment, I use my Stihl (Al Gore approved) gas leaf blower to clean out my table saw, router table and sander in the backyard. Works like a champ. It is even better for cleaning out my Ford F-150 interior. I start her up, open the windows, turn on the air (high) and blast the interior. Way easier than vacumming. My wife thought I was crazy until I demonstrated the advantages of the leaf blower.
+Eric Reicher I like the leaf blower idea, Eric. I just use my air compressor to blow off the tools and work area. Rusty hates it and hides, but it works pretty well.....and I'm sure old Al would approve :))
So very interesting, you sir are a true perfectionist and craftsman, not too many people are talented as you are. Well done and thanks for your videos.
Thanks so much, Jeff :)
Very impressive. It almost makes me want to build my own chassises. You explain it very well. You were an instructor in your former life?
I think Rusty should renegotiate his contract. He is becoming quite a celebrity.
+Steve Dewitt Thanks so much, Steve. Yes, I was a math and science teacher for almost 20 years. Don't tell Rusty, his agent is already squeezing me for a raise and perks as it is :)
Thanks, UD! I used that technique to cur my speaker baffle. It was accurate, and gave a lovely clean cut.
It's the new way of cutting baffle holes, Colin......no more wrestling with a saber saw. Thanks to the viewer who recommended it.
Hi Uncle Doug: Another great video. I honestly find you do the most thorough and informative videos. Using them as a guide, I will be able to take my amp building level to a whole new height. I am glad you are doing a Supro design, because I was thinking of building one earlier, (I'm a Jimmy Page fan), but I couldn't find the proper info on how to do it. I eagerly await the next part. thanks again, Bob
+starlingave Thanks so much, Bob. It's great to hear that the video series is helpful. Thanks for watching, and best of luck with your Supro project :)
I'll be back building another amp myself... thanks for the inspiration. As of now I'm working on a really luxurious DI box for a client.
+DeadKoby You're welcome, DK. Let us know what the project is and how it turns out.
Another great video UD. Rusty was in rare form, I think he's earned another cookie, however, like me, he may not need one!
+wreckoningday Thanks, WD. Rusty wrote the script for that scene and played his part quite well. His pay was two cookies, so he ended up doing very well indeed :)
GreatJob uncle Doug. Please don"t stop.
+joegile Don't worry, Joe. I'm as anxious as you all to see and hear how this turns out.
I love T-storms! Thanks, Uncle Doug!
So do I, Maurice.....they are very rare around here :)
HEY UNCLE DOUG I Like the way you explained everything on your videos. Nice and easy. Waiting for part 7 an the rest of your serie NICE WORK en thanks for all your great videos. Greetings Hans ( Holland ) and for Rusty and Jack a hug.
+Hans Hoek Thanks so much, Hans. Rusty, Jack, and I all appreciate your kind appraisal of our work, and wish you the very best :)
What you might want to consider is what I did for the Magnaclone: get a scrap piece of wood and use wood screws to mount the terminal strips to it (lay out the terminal strips with the same measurements they'll be in the chassis.) This lets you wire up almost everything, without having to work inside the chassis. Once you've got the terminal strips wired up, you can transfer them to the chassis, screw them in (or rivet, in your case), and then just run wires to the tube sockets, pots and transformers.
I got my terminal strips laid out in the chassis the same way you did, then drilled their mounting holes. Then I stuck a board under the chassis and marked through the holes with a Sharpie. Then I just used some short wood screws to hold the terminal strips to the board while I soldered the components on.
+catdumpling What a great idea, Cat. Thanks so much. It's always good to hear from you :)
Precision where it counts... Every step of the way!
Thanks, John. It sure cuts down on the problem solving later :)
Hello Doug
Really coming together great. Seems Jack and Rusty have traded places.:) Enjoyed and looking forward to your next video in this series.
All the best.
Bobby
+Bobby Tectalabyss Thanks, Bobby. It is progressing well, I think.....and the end is almost in sight.
Uncle Doug
I am really enjoying this series and will hate to see it end. Red is my favorite color. I hope sometime you do a video of building a cabinet with red Tolex. I know you have already picked the color and will like whatever you pick. Well I am rambling Lol.
All the best Doug.
Bobby
Good news, Bobby. I just got home from the vinyl store and red is one of the colors I selected.....partially due to the bright red covering on the original Supro in Part 1.
+Uncle Doug . That's Great ! :) Thank you for all the time you have put into all the videos you have posted. Much respect Doug.
All the best.
Bobby
You're welcome, Bobby. I think you'll really like the materials I chose. I'm now anxious to cover the cabinet.
A magnificent video Doug. So many thanks for sharing the secrets of great amplifier making. Jack and Rusty are as engaging as ever.
You're welcome, SS......glad you enjoyed the series.
Incredible craftsmanship. Looking forward to part seven!
+Slugg0matic Thanks so much, Randy. I'm really happy with how it's turning out.
I can't wait to see the next part! These 18 minutes passed way to fast.
Great Video - entertaining and informative.
+PrinceOfBodom Thanks, PB. Glad you liked it :)
Well done! Looking forward to part 7.
+redfishbum Thanks, Red :)
Nice work...looks factory! The wood looks so nice, I'd be tempted to stain and varnish it! Like the joints!
Thanks, 74Dart
Hey Doug, another great series. While I completely understand your choice of chassis material, I will point out of couple of things for followers who may not be familiar with hot-rolled sheet steel, which is what you used. That "blueing" is actually mill scale from the hot-rolling process and it's a lousy conducter (makes poor grounds but a GREAT capacitor, though). That stuff fiercely resists TIG welding unless you've scrupulously ground away the mill scale and cleaned the weld surfaces with alcohol or other appropriate cleaner. Additionally, if you live in a moist climate such as Middle Tennessee (Nashville) where gulf air is constantly streaming up this way, that steel is going to start rusting five minutes after you drill the first hole. Then, you're left with the option of painting (after grinding away the mill scale as paint won't stick to it) or throwing it away and selecting a more suitable chassis material. Please understand this is not a criticism of your choice of material. For just a few bucks, on the other hand, a metal distributor will sell you aluminum (or steel) "drops" for a fraction of the price of a sheet. An excellent choice might be a 5052 alum, for example, in .040 thickness. Easy to bend, MUCH easier on those expensive step drills, etc. And lastly, speaking of drilling, oil products never make good coolant for drilling as they lube the material instead of cooling it, which is the last thing you want. It LOOKS like you're drilling when you're actually rubbing your way through it. The MOST effective, and least expensive cutting fluid that I've ever used for drilling is a 50/50 mixture of Pine-Sol and tap water. Just my $.02.
Wow, thanks for the very informative input, Bruce. I have used aluminum for chassis in the past and found it easy to work, but difficult to bend without getting stress cracks. Most of the steel I use does not have mill scale, and with our 6 to 8% humidity, rust is not a big issue.....but I fully understand that it's a real problem in many parts of the world. I have been using a special cutting and threading fluid, but will definitely try your Pine-Sol recipe. Again, thanks so much for sharing this info with us :)
There are actually two reasons that stress cracks develop in aluminum during bending: 1) the heat treat of the material, e.g., T3, T4, or T6 doesn't lend itself to working and 2) your bend radius is too tight for the thickness. For small amp chassis of the size we're dealing with here, 2024, 3004, 5052, or 6061, CONDITION O (pron "oh") alloys in .032 thickness would be PLENTY strong enough and EASILY cut, drilled, and bent. Using the bending process you demonstrated here would work perfectly on a piece of 2024-0, .032 and be fully as strong as that safe you built from the HR piece of steel. Please forgive for the crack about the "safe" - that appeared at the doorstep of my tongue and I was powerless to keep it from just tumbling on out there. Best wishes.
I never cease to be amazed by the wealth of information available from viewers. I am taking some notes regarding the alloys you recommend, and will do some experimenting in the future. Thanks again :)
I'm loving these videos. Thanks Uncle Doug!
+sa230e You're welcome, SA. Glad you like them :)
Excellent again. Very good advice regarding the output transformer being off-axis from the power transformer! I didn't know that.
Also, you aren't there yet, but reverb pan orientation is important. You don't want the output transducer/pickup of the reverb pan to be at the same end of the cab as the power transformer or it could pick up noise from the transformer.
+tremelo68 Thanks so much, Trem68. You're absolutely correct about the output transducer being as far as possible from the PT. Over the years, I have observed the hum that can occur if it isn't. It's probably one of the main causes of reverb hum problems. Hopefully, the Supro will be totally hum-free :))
Good series. Looking forward to part 7
+FatBear Music Thanks, FB. It should be posted soon.
excellent video series! I'm anxiously awaiting the following installments!
+Daniel Gomez Thanks, Daniel :)
your craftsmanship is beautiful. I like your dog rusty too.
+smallenginedude71 Thanks, SED. We've posted 128 videos so far, so please check out some more when you get a chance :)
Uncle Doug i will definitely be doing that for sure! you earnt yourself a subscriber today :)
Welcome aboard the "Rusty Express".....we hope you enjoy our videos :) Thanks for subscribing.
I'm really enjoying this build! Thanks for sharing!
+Todd Patterson You're welcome, Todd. Glad you like it :)
What a great series of videos. Really entertaining and useful.
+BradAu73 Thanks, Brad.....glad you liked the series :)
Another great one, Doug...and since i bought myself a router years ago, i always use it, makes things a *lot* more easier, just as you shown in here as well...:) :)
+TubiCal Thanks, TC. It's definitely my new way to make holes in speaker baffles.....fast, safe, and very precise.
Really makes one appreciate just how labor-intensive it is to build an amp from design and construction, to finished product. I can`t imagine how one would put a price on the blood, sweat, and dog biscuits and still call it an affordable amp once its all said and done. I know its not an amp you intend to sell really, but more of a personal endeavor and a hobby for your own enjoyment. Lastly, and it shouldn't be a huge concern as I wouldn't think there are any nefarious characters lurking in our midst, however, you may want to blur out your license plate of your Jeep just to be sure. There is a tool in editing that provides that `blur-out faces` feature. I`m sure it would work for license plates just the same. All the best good sir, and looking forward to the final chapter in this series. Cheers!
+Krang Gangs You're right about labor-intensive, Lee. Each time I build one of these, I am reminded just how much work is involved. I can see why mass-produced cabinets (in foreign lands with low wages), printed circuit boards, and robot assemblers all came into being. Re the license plate, it was an oversight and probably can't be remedied once the video is posted. I guess if anyone wants to drive all the way down here to face Rusty's fangs, claymore mines, barbed wire, and five clips of .45 ACP to steal an old Jeep and some homemade amps, then there is just no stopping them :)) Thanks for your concern.
Really enjoying this series. Thanks.
+wardcheryldarcie You're welcome, WCD. Glad you like it :)
Wow, what a fantastic job... that is a quality build !
+Mark Jordan Thanks, Mark :)
Really nice work; the perfection of all the rounded edges is amazing and the cabinet looks gorgeous. I must congratulate you on some of the original idea's to bring this project to the point that I now see. "Incredible"
+John Cunningham Thanks, John :)
Great idea with the router for the circular cut ,thanks
+reffoelcnu alouncelal Thanks, Ref. It was suggested by some viewers, and it really works better than the %#$@&% saber saw :)
Really impressed . All my amps have had the transformers on the other side and the input section on the opposite side also so struggling to get my head round a "mirror image " amp. Also I've built from plans and turret boards . so tag strips will be a new challenge .
Good luck with terminal strip point-to-point wiring, Doc. I hope you like it.
Great series of videos Uncle D.
Thanks, EH :)
Informative , meticulous ,and fun,love it
+jadefire1985 Thanks, JF :)
poor rusty, got ripped off...lol...looking great doug, a great series..
+100roberthenry Thanks, Robert. Don't worry.....the scene was Rusty's idea and his acting fee was two cookies :)
uncle Doug good video very cool build thank you
+John Sherwood You're welcome, John. Glad you like it :)
fantastic vdo, Uncle Doug!
Glad you liked it, Kenny :)
nice work! love the dog too, best greetings from Belgium
Thanks, Mario, and regards from both Rusty and me.....in the hinterlands of far west Texas.
Jack is such a cutie!
He's not just a pretty face, either. Rusty is good at backgammon, engine tuning, arc welding, and singing......whenever he hears a siren.
Thanks Doug to the info really enjoy and you give me some good ideas.
Jerry from mid MO.
+G Edwards You're welcome, Jerry. Glad the videos were helpful :)
Outstanding! Looking good.
+MrOldnslofly Thanks, Mr. O. It's progressing, slowly but surely.
I really enjoy your videos very well done thanks you
+Jim Lundin You're welcome, Jim. We appreciate it :)
use a drilling lubricant! Brilliant! Having just done this a few times DIY, it never would have occurred to me, but it makes perfect sense. I was a bit surprised that you used porcelain tube sockets. My preference is to use those dirt brown Belkins. I often will design my amp's faceplates on my laptop, and lay it out real nice and have that made before I drill the chassis. That way I can get it to conform to the faceplate perfectly. It helps that I have some background in graphic design.
+Alva Goldbook Yes, by all means use a proper lubricant, Alva.....and not WD40 or some silicon spray. I use a special machinist's lube that is specified for drilling and tapping. It makes the difference between a 3-second drilling time and a 3-minute (smoking, bit-destroying) drilling time. Your faceplate idea sounds great. I hope mine turns out nearly as well :)
+Uncle Doug I get my faceplates made for around $35 each. It ends up being pricey this way. One of these days I'll set up my own silk screening station, but this is how I do it for now. Here's the faceplate graphic I designed for that rebuild of my Fender Hot Rod Deville into a blackface type amp I was talking about earlier. The spacing of the holes are based upon the existing chassis.
i.imgur.com/1PjRAZQ.png
It looks very professional, Alva. My designs are much simpler.....and less expensive :)
Hey Uncle Doug, how about a nice clear lacquer finish. I really like the look of a pine cabinet with a clear finish. Your covered cabinets are beautiful as well :)
+Aerostoon Thanks, Aero. I would like to make a natural wood cabinet. Maybe on the next project :)
This is golden info!
You think rain is fun...hmmmm,come live in scotland for a week,that'll cure the love of rain.
Seriously,love the vids,even though it's been 4yrs,tubes are still timeless,what is it you guys say "keep on truckin'|".
Here in the desert, rain is a welcome distraction, John......but I can see where it might get old if present in excess. Thanks !!!
Beautiful.... ..Nicely & Artfully Done.....(Milling is always the way to go if you can do it). Good tip on the transformer placements...changing the angle of attack to a right angle on the magnetic fields...so that it may might be less likely for the fields to interfere with each other ....very good . The Devil is always in the details.....excellent ! ;D) B.
+William Earney Thanks so much, William. I have a mill, but have always simply cut out the transformer holes. Glad you liked it :)
+Uncle Doug and Rusty......Actually I was referring to your use of the Router table to "Mill" out your speaker baffle opening....."wood milling".....I should have been more specific.... but now that you mentioned it.....wouldn't be wonderful to have one of my old "Bridgeports" setting in the garage to take on those pesky metal cutting/ milling chores.... Hah!! ......Cheers...Bill
Bridgeport mills are wonderful, until it's time to move one :P I have a small mill, but only use it for tasks that can't be done in any other manner, due to the required set-up and clean-up time.
It was like I was looking over your shoulder! Are you going to make or order the dash/faceplate? Man that is a great idea to install terminal strips. It will cut back a little on over all weight and be so easy to wire to. Brilliant! Your production crew seems a little bored. I guess they can't wait to smell the completed amp. Thankz
+Audio Tech Labs You're welcome, ATL. I will make my own nameplate, as described in one of my videos. Glad you like the terminal strips. Usually, two parallel rows, almost full length, will do the job. I may have to add a couple as the wiring progresses.
Uncle Doug, to think I have been doing it with a sabre saw for eons. I have a router table in the garage and never thought of using it. I award myself the DUMMY of the century award. LOL.
+Eric Reicher I've been suffering with the saber saw for years, Eric, but not any more. The router is way better at this task.
hey......a contracts a contract. coming out incredible. nicely turned that nice piece of cold rolled into swiss cheese. I've got a nice set of greenlee KO punches thattle come in handy for this. off to favorites.........
+R HEIDEMAN Thanks, RH.....glad you liked the swiss cheese :) Rusty has a good stout bark, but when he's begging for a cookie, his voice shifts to become almost a cough. I have no idea why. Maybe he's just being polite :)
Uncle Doug he knows whos boss. Besides he probable doesn't want to miss any pertinent info. He can't rewind it like i can. Have an awesome day.
Thanks, RH. He who dispenses the cookies is always the boss :)
Nice as always! Looking forward to part 7! :-)
+LowEndStrings Thanks, LES :)
Looking at how nice the routering came out I would be temped to stain and varnish the bare wood.
+Arnold Rimmer Thanks, Arnold. I am tempted to build a bare wood cabinet, but would want to use a more attractive wood than pine.....perhaps mahogany or (expensive) walnut.
thanks for the tip . as far as the carpet tape I found a better way regular masking tape and super glue . put the masking tape on the template and the workpiece then a thin bead of super glue holds much better . cost much less and is much thinner. I use that to make inserts for my saws . to cut out vents in back panels any number of things. thanks again
+Jim Lundin You're welcome, Jim, and thanks for sharing your methods. We appreciate your input :)
Man with a plan.
+MrMac5150 You must be a fan of "Things to do in Denver when you're Dead", Mr. M......one of my favorite shows. Let's hope we're never on the receiving end of a "Buckwheat" :)
Nice Work!
+su pyrow Thanks, SP :)
Amazing job.
Thanks, Cesar :)
love the series, give rusty a cookie from me!
+Sondretheman71 Thanks, SM. Rusty agrees with you :)
If I was a manufacturer, I'd approach you for your prototype... but my question was, did you consider plating the chassis? ...and though I know the cab will be really boss (or 'dope' or 'bomb' as the youngsters say nowadays) with the covering, I can't help but wonder how she would've looked with a natural or a sunburst finish... But no matter as I know it'll be smokin' in the end (;-b)
Oh and also, I'm so glad you hinted at the possibility of using a 6L6 or a 7027 or 6550 for those times when a bit more power might be desirable...
Really enjoying this series. thanx and...
cheers
Keep watching the series and see what you think, Jonny.
love your video this is a really good build how i want to be come as good as you
+ian “valve doctor” forster Thanks, Ian. Just like with musical instruments, all it takes is lots of practice :)
Most Impressive.
+Watchman4u Thanks, W4 :)
Excellent Uncle Doug !! While watching and listening to you handle the 16 GA chassis - it sounded so very solid - I was wondering how much it weighed !! I noted your earlier comment that perhaps 18 GA would have been adequate. Any conjecture as to how much lighter that would be ? Thanks for all the great videos !!!
+Donald Filbert It probably weighs 3 or 4 lbs, Don. I would think in 18 gauge it would be about 20% lighter. It is really solid, but machined up without any problems. You're welcome for the videos. Glad you enjoy them :)
If the main filter capacitors at the power nodes are rated
At 500 to 525 volts DC
you could run a 5AR4
when running the 6L6
and then the 5Y3
when running the 6V6
even with the 2 position bias switch
That way both the
6V6and6L6 can have two power settings each.
Thanks for your helpful input, Dwight.
We're all enjoying this build immensely! Doug, what gauge is the sheet metal of your chassis? I'm making a new front panel for my variac and I'm wondering what gauge metal those step bits will go thru. I'm pretty sure what I currently have is 15 ga. Needs to be fairly heavy to hold the variac mechanism. Thanks again for the great videos!!
+headinsouth1 You're welcome, HS. I used 16 gauge for the chassis, which is about .060" thick.....very stout. The step bits didn't have much trouble enlarging the holes, especially when properly lubricated.
Hi, Doug. This is truly inspirational. However, isn't it easier to drill and cut the chassis before folding it?
Perhaps, if you have proper bending tools, Nathan, but I've found that if you drill before hand-bending, the metal around the holes may deform.
I was wondering how you’d upholster the cutaway for the controls.I’m sure you’ve noticed that Fender and vox have an upside down“V” cut with a strip under it in the corners. I wonder why they don’t just do the controls the same way as the oval cuts on the back of amps.
It has to do with the radius of the curve and the thickness of the wood being covered, William. The rear panels are much thinner than the top panel and the covering material can be stretched without cutting.
@@UncleDoug Thanx UD. Makes sense. I was wondering how I was gonna approach that if I make a control cut out. I’ll keep thickness in mind.
Cool series! Thanks! Are you going to plate the chassis?
+stekks Thanks, S. No, I'll probably either paint or clearcoat it. The problem is that any coating will probably interfere with proper grounding.
very nice
+raw5069 Thanks, Raw :)
Hi Doug! Do the rubber grommets serve a function other than protecting the wires from sharp edges? Do they prevent inductance or something? I just noticed that my amp doesn't have them. Thanks! ...and as always - great video!
+HungryFreaksDaddy You're welcome, HF. As far as I know, it's just to prevent chafing and possible short circuits. Lots of amps don't have them.....but to be honest, they probably should. I always feel safer with them. If you don't have them, you could wind some electrical tape around the wires where they pass through the chassis wall.
I've been meaning to ask you, Uncle D, that's a cool little router table you've got. What brand is it?
+Alva Goldbook It's a Vermont American brand, Alva, possibly defunct by now. I bought it at least 40 years ago. It's solid steel, unlike the "modern" ones which are probably plastic.
how well did cutting out the hole for the speaker work when you routed the last bit of it . I am very interested. I build cabinets every day I have tried several ways and have thought about doing it like that but figured at the very last inch it would cause problems . I use templates I originally made by bolting a speaker to ply and using a flush trim bit the bearing riding on the speaker basket or more correctly the foam or cardboard gasket. but from many uses the templates wear out mostly from putting the studs through them
+Jim Lundin Make a template out of 3/4 inch plywood. Spray it with several coats of polyurethane. Use double stick carpet tape to hold it in place while you cut with a template router bit. ( bearing on top) if you don't spray the template the tape will peal the wood out in chunks after lots of use.
+Jim Lundin It worked perfectly, Jim, all the way around. I too was worried that once the center circle was freed from the baffle, the baffle might wander and get chewed up.....but there was no problem at all. I was using a straight-sided, unpiloted bit and maintained good control over the baffle at the end.
Hello Doug, do you intend to spray the outer of the chassis. I think you live in a rather dry climate area so moisture and rust on the steel may not pose a problem. Here in NZ we get 4 seasons in one day, so I would think spring or powder coat would be ideal. You do need bare metal for the grounding though don't you, especially the ground bus if there is one???
+allanpennington You bring up a good point, Allan. It's very tempting to either paint or clearcoat the entire chassis, both for appearance and rust prevention, but then you create grounding issues, so it's kind of an enigma. I'll come up with a solution.....I hope :)
+Uncle Doug was going to ask about this myself. paint is important but so is proper grounding. what if you rivet all the holes (and keep them hollow) , mask them out and paint the rest of the chassis?
Believe me, I'm trying to come up with a practical approach, Szymon. Other than using stainless steel for the chassis, any ferrous metal presents this same problem.
to be fair.. the grain is nice and it would look nice with just some finishing oils too imo :)
Maybe for a future build, JJ. Thanks for the input :)
Hello Doug: I know that you like to keep your chassis small. Is there any concern about the PT and/or OT being close to the speaker magnet?
Not really, Mark. The main concern is having the preamp section too close to the power supply.
I have a question Uncle Doug if you can get around to it. I have watched your videos many times, and i mean a lot. I understand so much now about tube amps, but one thing still puzzles me. On a fixed negative bias, many amps will have two 220k grid leak resistors to the bias. Wouldn't this drop the bias voltage almost to zero at the grid? Or is the grid leak resistor calculated in having a higher negative voltage accounting for the 220k drop before the grids? That is the only thing that confuses me. Thanks! You have taught me a lot.
You are assuming that high value resistors will substantially reduce voltage, Joshua, but in reality, the voltage drop is based on current flow. Thus, if virtually no current is flowing, a 1 Meg Ohm resistor might not cause much voltage drop at all......while in a high current line, a 10 Ohm resistor might create a significant drop. In bias lines there is virtually no current.....where would it go? The grid is essentially a dead end.
Okay, that makes since. You are awesome!
Thanks !!!
Uncle Doug - do you believe there is any advantage using aluminium for a chassis?
I’ve heard it reduces magnetic interference and could make for less hum.
What’s your opinion?
Thanks
I've used both it and steel many times and find no EMF benefits, but it's easier to machine than steel, weighs less, absorbs and transfers heat quite well, and won't rust. On the downside, you can't easily solder to it.
Very nice amazing gob
+Chris Barnes Thanks, Chris :)