Steel guitarist and electronic guru Freddy Tavaris dropped in to Fender one day to complain about problems with Leo's amp designs. Leo hired him on the spot and he remained his technical right hand man, staying with the company long after the CBS sale. Many amp improvements were made co-incident with Tavaras joining the company. It may be possible that the changes seen in this amp early in its production were done by him. I'll need to check my books to confirm the dates, but its in this general time period. Also, everyone blindly gives credit to Leo for everything related to the company... which is not the way it was. His business manager Forrest was also a brilliant production engineer and totally changed the factory floor layout and materials handling.. as Leo had a freaking mess of a shop with no inventory control. Much of the product design came from George Fullerton and Freddy Tavaris. Leo hired a few great people in key positions that had a major impact on the positive evolution of the company. Sadly, when he sold to CBS, non of the key people were included in any way in the massive profit that Leo took. Forrest in particular had been offered a share of ownership that was never, NEVER, followed through by Leo.
As it is today, in history we always find very successful and famous people that promised a lot to the real geniuses but never delivered. Have you heard of a “genius“ called Steve Jobs? I bet you did! you’ve heard a lot about him, read the books, watched the movies, listened to the soundtracks, BUT very little was said about the other Steve! Yes! The other one! What is his last name? Oh yes, Wozniak! The one who actually MADE the computers and took a lot of Shit from the so called“genius” during the process. This is typical of many situations where a name is mentioned while it’s not the one actually doing it. Not saying Leo wasn’t capable of (much better than Jobs), but it would be very noble to mention all the people responsible for the great products and give them what was promised. Very sad to hear that. He was one of my idols from that era and considered him an innovator but never knew he could be that way.
AnticommentWarrior He was tired, and wanted to enjoy some play time.. He took millions, bought a yacht and went boating... He did try at some point to make it up to both Forrest White and George Fullerton by starting small companies with them... The venture with Forrest lasted only a short time, but the other stood the test of time, that being G & L.., George and Leo. G&L still survives as a company, and still has much of the original shop equipment that was once at Fender, all sold when CBS built huge new production facilities. There are youtubes of tours through G&H talking about all the surviving Fender benches, cabinets, and even drawings.
@@roadshowautosports Thomas Edison has to be the ultimate example of this. How many of 'his inventions' were actually invented by him? The more you delve into it, with reliable citations/evidence, the darker it gets, really quite depressing. Arguably his success could be attributed, along with undoubted intellect, more to Machiavellian psychopathy than to genuine genius like Nikola Tesla. For clarity - I don't place Leo Fender in this level of category! As it appears to me, Leo Fender was great &, like most people, part good & part a bit of a sh¡t.
Brad is BACK!!!! Nice to see you working on amps and sounding more like yourself again :) I watched every second of the video, loved it all especially the added history part at the start!
Hey, Brad, thank you for all of your videos. I confess that on the time I’ve first saw your videos i sincerely thought you were an amateur trying it ou things on electronics! I guess by your simple way of talking I couldn’t see the master of this craft that you really are! I’m amazed by the way you can troubleshoot every defect by just simple hints in the circuit! You always start with s simple “I bet...” and your intuition is pretty much on the spot! Sometimes, like in this video, by mentioning possible causes for the humming, you made it look so simple and intuitive while taking away the fear we all have of amplifiers. I didn’t even know one could remove tubes while the amp was ON!!! From there you show such a professionalism and care for the subject as well for its owner when trying to keep it original but functional. Another great quality of yours is how humble you are by not editing so much out of the final product to show how you finally find out what is causing it, your own “mistakes”, and how you got to the solution! You’re a blessing! Thank you!
Great to see you’re doing a guitar amp centered video again! Btw I’m not here only for the amp content, I do in fact enjoy the majority of your content.
I agree, that was the whole reason I came to this channel in the first place. His channel kinda fell off my radar lately so I hope he continues to bring more of this content.
Wow, not knowing squat about electronics, this was like all Chinese to me, but this video captivated me from start to finish with the patience & persistence you took tracking down the noise issue. That’s what separates the men from the boys in my opinion. As many times that must have been in for maintenance and buttoned back up without anyone noticing the grounds at the input jacks along with everything else. Amazing, I’m totally blown away, & them some sweet sounding chops to boot. Made my day, thanks.
Now that's an amp! Love the old tube amps of the 50's. Getting rarer than hen's teeth to find! Thanks for sharing this one with us! There's a reason why those are Clapton's favorite!
Man I love watching those 1h+ vids while working on a guitar. Lots of stuff I learn just by listening in sometimes taking a break from guitar and watching the content up close. Very interesting insight on the history and schematics, cant appreciate enough what I learned on your channel.
Hi Brad, I am a technical officer of 40 years experience. You have noted in other videos that some people have commented on the things you show or not show. I for one appreciate the the need for keeping videos short and or condensed. For me I completely understand and support what you do. I find it informative and entertaining. Please keep up the good work! Alex
the 220uF capacitor he installed is a Polarized capacitor. The Capacitor before was a 50uF Bipolar. BP or NP. NonPolar. He replaced it with a regular Aluminum Electrolytic capacitor. Electrolytic capacitors cannot be used as a Coupling Capacitor unless its a Bipolar Capacitor. Either a cheap Non polar Electrolytic Capacitor or a Film capacitor. a Film capacitor can cost 100 dollars unlike the 10 dollar cheap Bipolar electrolytic capacitor. Audio signals stop when they meet a Polarized capacitor so it cant be used as a bypass capacitor correctly. the Polar 220uf capacitor is just charging up, thats why there is a lot of noise. Lots of people just opt for the Regular cheap Electrolytic capacitors in the Cathode. Marfsgall once used 330uF and now they use 250uF but Marshall only changes values when they use parts that are in stock. If you look closely at the start of the video, the big blue capacitor has in dents on both sides of the capacitor. the black capacitor only has an indent on the bottom side. Indents on both sides means its a Bipolar or NonPolar capacitor.
This video made me want to 1. Get myself a Fender amp (never owned one ever) 2. Get back to working on my myriad of unfinished amp and guitar projects 3. Get a Bigsby for my Tele Stellar video, these are the kinds of videos that made me subscribe years ago. I often watch these while doing fretwork on guitars etc. Keep 'em coming, and thank you for the awesome content!
how can you not love brad,this was great it made me open up my best amp a 1972 guyatone reverb jazz,basically a fender super reverb.and i noticed my tech did what brad did put in great caps and good pots.i love old amps they just do all you need
Brad you knocked this one out of the park. You are back and better than ever. I hope you continue putting out great content like this. We are pulling for you. Good luck.
Sweet sounding now i see why die hard electric guitar players love and want these old fender tweed amps. Learned something new today about circuits etc. I do love Hi Fi tube amps it warms up cds and gives life to vinyl! Thank you for posting!
This is one of the best amp projects that you have posted. The history and design era specific sleuthing to resolve the noise issues was so informative. It resolved questions Iv'e had with grounding design at Fender for years. Jennifer's comment is excellent historical input on who influenced the technical show at Fender. More please sir?
Excellent video, Brad. I’m glad you’re in a place where you can get top notch videos like this out to us! Great job dude, love it. 2020 has been such a bummer, I know you’re feeling it too and I just want you to know, whatever ideological differences we have, I really, really appreciate your knowledge on the subject of guitar electronics, which has turned out to be one of the most fulfilling parts of my life, thanks, in significant part to you and Uncle Doug for making it feel possible and straightforward. Keep it rockin’ man!
The 6SC7GT (G lass T ube, don’t) bother with the metal tube versions these are generally microphonic) tube is a dual triode but only one cathode 8 pin tube similar to the 6SL7 with cathodes and an amplification of 70. Sovtek sells the Rusky equivalent of the GT version for $40. Leo in pursuit of clean switched to the 12AY7 with amplification factor of 40 for the later tweeds and used a negative feedback circuit some Ea Bassman (with 10meg resistor, Pro Amp 5 meg resistor) ahead of of the another 12AY7 and 2nd tube used as part of a localized negative feedback so it couldn’t be overdriven removed (5E5A pro gad the with the F series A models. My oldest son owns a “The Pro” which was a special order E circuit with the 6SC7 preamp tubes (it had factory black faux Alligator instead of tweed, he saw a 2nd one while in college working in a guitar store, and I saw one on eBay decades ago in white.
Another phenomenal video Brad! Thank you for taking the time and effort to produce such quality content, never has it ever not been enjoyable to watch these with my full undivided attention. This definitely takes priority over watching an hour long episode of whatever the heck TV shows you'd find on a streaming service.
My God ,Dude. You are an engineering marvel. I have been sending your vids to my Son ,who is an Engineering major in college. Thank you for all you do !
I wonder if the tech before had stuck the 6SN7 in the mix position of the tone stack with the 50uf bypass cap. The lower mu tube may have allowed the preamp to load more into the tone stack. Interesting to have tried that with the tube complement originally supplied. Lot of work involved there, and time and money. Working on these older is always a challenge considering that Fender prototyped on the fly during this time. He'd loan an amp out, and someone would bring it back with comment, and they'd make a change. Jim Marshall was the same in developing his amps. Artist input was what drove the innovations.
The 6SN7 is a different pinout than the 6SC7, so I don't think they were using it in the tone stack driver position. But yes, the supplied tubes does leave a bit of a mystery... The owner did say when he dropped the amp off that one channel seemed to not be working at all, so I assume that's because there was a 6SC7 in a socket re-wired for a 6SN7. I'm sure the amp would be more flexible with a different tube in the V1 or V2 position so that channel would respond differently, but in this case, I think re-wiring to factory spec was the right move because of the historical interest of the amp.
Great tutorial on vintage amp repair and troubleshooting, and amazing focus and determination. You stayed with it until you got it right. Brad is back! and nice tip o the hat to EVH. Thanks
I think like a lot of other people, I've been reconnecting with Van Halen music since his death, and we really lost a luminary of massive importance. That much is clear.
Been watching the SRV aladdins cave vids.I been at this game a long time,lucky enough to meet Jim Brian May etc. But this pair of videos are no 1 to me, you are some player Mr Linzy.Salute
Hey Brad, Oddly enough, at the 5:50 mark of your video, you can see a "550" stamp on teh the right speakerl frame. The white "550" ink stamp was a code that went on all speakers in Valco amps back in the day. I don't know if Valco put the stamp on there, or if Jensen did, but it's factual, all Valco amps had a 550 speaker stamp, whether they were from Rola or Jensen. Leads me to think someone may have pulled these from a Valco amp to replace blown originals.
@@RedGibsonsRock Their PM (alnico) speakers are great. I've stuck P15Ns in all my Thunderbolts. I started buying them up years ago in the used market for future replacement. The coils seem stout enough, but after all these years, they can be prone to develop mechanical problems-- vibrations, buzzing etc., as glues get more brittle and give up their bond.
Bearing in mind that speaker technology has progressed in materials and industrial design over sixty years, it seems that later replacements, even of different manufacture, could only refine and improve on the sound originating from the original electronic 'recipe'.
Thanks Brad! This vid was truly entertaining. I was with you the whole time. I was glad when you decided to redo the heater wires and put a virtual tap to ground. I've had to replace jacks on a amp, which had no extra ground lugs. I wish I could show you a picture of the different style jacks I put in. The nuts are wide stainless steel, looks crome plated; decorative. I can't remember the name or where I got the first ones. I think they were given to me to try out. Bit it did make the amp look better and no noise.
Great job of sleuthing those troubles away! Even though I have been in the electronics game for many moons I continue to learn new stuff from you. Keep it up.
In 2003 I was in the shop picking my 68 twin and a fella walked in with his 52 twin. He was the original owner wanting to get it checked out before selling it. This gentleman was in his 80’s and used this amp all throughout his career as a steel player. I played it. It sounded like a toy compared to the high power twins. It broke up early but not as early as the 52 Deluxe I had the good fortune to play through. They both had similar tones. The twin was just a completely different animal compared to what I was used to. He was trying to get 6000 for it at the time. I wonder if he ever got the money he wanted? I enjoyed more so just meeting this man and having the connection with history.
Beautiful homage to EVH with 1984 in there. Cool vid and never realised the old Fender twin could get such a gritty sound!! Possibly why Eddie himself used Fender amps back stage in the warm up room!!
I was working on a tweed bassman today. It had the same noise and microphonic issues. I thought about emailing you for a solution, but then I decided to man up. Perhaps subconsciously remembering what caused the noise issue with the non grounded input jacks from this video made the fix quick and easy. It wasn't acting like an asshole because of all of the ways it could, it was behaving exactly as it should with ungrounded multiple inputs.
Hey Brad!!!! I really enjoy your channel, tech chops, and musician chops. According to Aspen Pittman and certain associates of Leo Fender, Leo resisted attempts from his design engineers to stabilize the output of his amplifiers making them more linear and audiophile. Leo knew that his claim to fame was that when his amps were pushed to clipping by musicians of the day they cipped musically and this is what sold Fender amps. The first thing that Leo's design engineers did after the CBS acquisition and Leo's departure was to design Ultra Linear amps to stabilize the output of Fender amps like the silver face Ultra Linear Twin 135 Watt Amp. Leo hated this. Leo loved the fact that his amps clipped musically and was averse to the new 'audiophile' direction that his engineers pursued. JAFWIW
I was super happy to finally see an amp video again. Then I was even happier about the new format and production quality... then I saw Brad wearing a Tool shirt. All is right in the universe. Glad you're back, Brad.
Good to see you back on amps brother. I'm hoping 2021 will see us ALL better and shaking off what can only be described as the bastard of years, 2020. Here for ya any time bro.
That's awesome, and a cool coincidence. I recently scored a '57 Twin reissue on Reverb that had some heavy abuse, I've repaired the cabinet and just dropped it off yesterday to amp repair guy. I'm pretty excited to have one again, just a couple years ago I sold a '61 that I grew up with, and I was kind'a missing, even though it was such a beast :0)
These days, a 1953 Twin would come with its own security guard. Even in that state, that's one highly desirable amp. Great to hear you playing again, too.
I have one of these Twin Amp's, mine dates to 1954 pots & speakers but the tube chart is long gone and mine is the next version with 12ay7's pre amp tubes, but still with only 4 control knobs- appears to be a mix of 5C and 5D circuit..
Brad, you are like the guitar gear whisperer I swear! Fantastic job dude!!👏👏🤘☝ Awesome video and great to see you back digging in an amp as it seems to be your passion. I want to thank you because after stumbling onto your channel a couple years back you really peaked my interest in the electronics side of gear. I'm happy to say as a result I just built my first pedal, a replica of an early Dallas Arbiter Silicon Fuzz Face circuit....and it works!! Lol!! I even built it using some nice transistor sockets so I can swap them out to try different ones easily. Stoked to build another one and even have my eye on an amp kit at the moment. Anyway thanks man, I really appreciate your channel and all you put into it!! Hope you're well and keep up the great work my friend!
what is that device called that's siting up high to the right (around 53:34) that reads voltage/ current/ power/ energy? It looks like it is attached to a variac, or can you buy them with that display? I have not seen anything like that with all those read outs. Is it something you buy separately and attach to a variac?
Having built an all octal amp in the past, they can be challenging preamp tubes to work with. Much of the used old stock are either microphonic, noisy, loose bases, etc. But man when you find a good one they sure are sweet sounding.
Dear Brad, thank you very much for your interesting and helpful videos! Be blessed, healthy and happy, and I wish the same for all the people around you, and all your UA-cam audience! Greetings from Bulgaria! :-)
Fantastic segment/topic . Plenty of people on UA-cam show and play these thing. Giving us the TONES!!!! And that's all well and good. We all benefit watching those vids. But there's always more to the story. You going through, and giving us the history the way you do, is also just as important to the full story of these amps. Personally: I LOVE THIS SHIT, hahahah. Good to see you digging into your interests a little more. Great stuff, man!! Cheers from Akron, Ohio.
This was my second experience with them in an old Fender. I think they offer a high-end feel to the project. Anyone who opens the back to inspect it should be impressed with the component selection. I think it just shows someone competent cared about it.
Instead of obtaining an elevated voltage for lifting heater circuit virtual center tap from one of the tubes, it is customary to create that elevated point with a pair of resistors as a voltage divider right off the B+. I usually use a 1 meg ohm off the B+ and select the ground side resistor to get the voltage I want, which usually ends up being about 221K. From that junction, I also use another 1meg as a current limiter that go off to the center tap or virtual center tap. All that is needed to lift the heater circuit is a very very low current "electrostatic" offset voltage.
Great suggestion. I'm seeing some schematics using 330K to tap off the B+ for creation of such a node. I might try that sometime on a project. Increases the parts count though. That's one drawback I can see.
@@TheGuitologist Parts count of 3 resistors... a dollar ... plus being an isolated circuit, it is adjustable by simple part substitution to any voltage you want, and more important, your not tying any extra crap right to your audio circuit.
Man that amp has got mojo. You know why so many top players use them. I had a 25 watt version from ceriatone that I put in a 112 cabinet. I sold it a while ago , great amp that tweed circuit.
One of my first amp builds was a 5C5 'Pro' with the octal preamps. The natural roar as the amp goes (quite early) into overdrive is something that I haven't been able to recreate with pedals or other more modern circuits. Unfortunately the amp only gets up to maybe 18 watts so even with a 2-12 it struggles live without being mic'd well. But I'd love to build a 35-watt version, or look into the 5C8 Twin. That 6J5, though......
Yeah, honestly, none of the tweeds are all that loud by today's standards. I could increase the volume of this one by going 6L6GC and biasing to max. But it would stress the Jensen speakers needlessly I think. Anyone using this amp would probably mic it live anyway.
@@TheGuitologist right back at you Brad. Here in La reporting from the Apocalypse. Still working never get sick. Just have to put up with a bunch of a-holes. So-so average day in La not much has changed.
Steel guitarist and electronic guru Freddy Tavaris dropped in to Fender one day to complain about problems with Leo's amp designs. Leo hired him on the spot and he remained his technical right hand man, staying with the company long after the CBS sale. Many amp improvements were made co-incident with Tavaras joining the company. It may be possible that the changes seen in this amp early in its production were done by him. I'll need to check my books to confirm the dates, but its in this general time period. Also, everyone blindly gives credit to Leo for everything related to the company... which is not the way it was. His business manager Forrest was also a brilliant production engineer and totally changed the factory floor layout and materials handling.. as Leo had a freaking mess of a shop with no inventory control. Much of the product design came from George Fullerton and Freddy Tavaris. Leo hired a few great people in key positions that had a major impact on the positive evolution of the company. Sadly, when he sold to CBS, non of the key people were included in any way in the massive profit that Leo took. Forrest in particular had been offered a share of ownership that was never, NEVER, followed through by Leo.
I always suspected Leo Fender could not have pulled it off without unfamed gurus of his day.
didn t know
As it is today, in history we always find very successful and famous people that promised a lot to the real geniuses but never delivered. Have you heard of a “genius“ called Steve Jobs? I bet you did! you’ve heard a lot about him, read the books, watched the movies, listened to the soundtracks, BUT very little was said about the other Steve! Yes! The other one! What is his last name? Oh yes, Wozniak! The one who actually MADE the computers and took a lot of Shit from the so called“genius” during the process.
This is typical of many situations where a name is mentioned while it’s not the one actually doing it. Not saying Leo wasn’t capable of (much better than Jobs), but it would be very noble to mention all the people responsible for the great products and give them what was promised. Very sad to hear that. He was one of my idols from that era and considered him an innovator but never knew he could be that way.
AnticommentWarrior He was tired, and wanted to enjoy some play time.. He took millions, bought a yacht and went boating... He did try at some point to make it up to both Forrest White and George Fullerton by starting small companies with them... The venture with Forrest lasted only a short time, but the other stood the test of time, that being G & L.., George and Leo. G&L still survives as a company, and still has much of the original shop equipment that was once at Fender, all sold when CBS built huge new production facilities. There are youtubes of tours through G&H talking about all the surviving Fender benches, cabinets, and even drawings.
@@roadshowautosports Thomas Edison has to be the ultimate example of this. How many of 'his inventions' were actually invented by him? The more you delve into it, with reliable citations/evidence, the darker it gets, really quite depressing. Arguably his success could be attributed, along with undoubted intellect, more to Machiavellian psychopathy than to genuine genius like Nikola Tesla. For clarity - I don't place Leo Fender in this level of category! As it appears to me, Leo Fender was great &, like most people, part good & part a bit of a sh¡t.
Brad is BACK!!!! Nice to see you working on amps and sounding more like yourself again :) I watched every second of the video, loved it all especially the added history part at the start!
Thanks. I appreciate you watching.
Glad to see him back in 'in the realm' as well..
I love how you don't bullshit us. You show the issues you run into even after you have completely serviced it. Thanks for being YOU, Brad!
Hey, Brad, thank you for all of your videos. I confess that on the time I’ve first saw your videos i sincerely thought you were an amateur trying it ou things on electronics! I guess by your simple way of talking I couldn’t see the master of this craft that you really are! I’m amazed by the way you can troubleshoot every defect by just simple hints in the circuit! You always start with s simple “I bet...” and your intuition is pretty much on the spot! Sometimes, like in this video, by mentioning possible causes for the humming, you made it look so simple and intuitive while taking away the fear we all have of amplifiers. I didn’t even know one could remove tubes while the amp was ON!!! From there you show such a professionalism and care for the subject as well for its owner when trying to keep it original but functional. Another great quality of yours is how humble you are by not editing so much out of the final product to show how you finally find out what is causing it, your own “mistakes”, and how you got to the solution!
You’re a blessing!
Thank you!
Great to see you’re doing a guitar amp centered video again! Btw I’m not here only for the amp content, I do in fact enjoy the majority of your content.
Same here 👍
@@TJHill-fk1cp Same with me
ditto
Thanks for watching the vids. I appreciate it.
I agree, that was the whole reason I came to this channel in the first place. His channel kinda fell off my radar lately so I hope he continues to bring more of this content.
Wow, not knowing squat about electronics, this was like all Chinese to me, but this video captivated me from start to finish with the patience & persistence you took tracking down the noise issue. That’s what separates the men from the boys in my opinion. As many times that must have been in for maintenance and buttoned back up without anyone noticing the grounds at the input jacks along with everything else. Amazing, I’m totally blown away, & them some sweet sounding chops to boot. Made my day, thanks.
Now that's an amp! Love the old tube amps of the 50's. Getting rarer than hen's teeth to find! Thanks for sharing this one with us! There's a reason why those are Clapton's favorite!
I liked the info in the beginning! you should do that more often
Man I love watching those 1h+ vids while working on a guitar. Lots of stuff I learn just by listening in sometimes taking a break from guitar and watching the content up close. Very interesting insight on the history and schematics, cant appreciate enough what I learned on your channel.
Hi Brad,
I am a technical officer of 40 years experience. You have noted in other videos that some people have commented on the things you show or not show. I for one appreciate the the need for keeping videos short and or condensed. For me I completely understand and support what you do. I find it informative and entertaining. Please keep up the good work!
Alex
This presentation is over 1 hour and I showed less than half of the repair process. So you get it, I think.
Dude you are crushing it on the custom intro game
I have some very cool channel fans who made some of those for me. I made a couple on my own too, but theirs are better. :D
Great to see another in depth vintage amp repair vid. Keep them up Brad !
the 220uF capacitor he installed is a Polarized capacitor. The Capacitor before was a 50uF Bipolar. BP or NP. NonPolar. He replaced it with a regular Aluminum Electrolytic capacitor. Electrolytic capacitors cannot be used as a Coupling Capacitor unless its a Bipolar Capacitor. Either a cheap Non polar Electrolytic Capacitor or a Film capacitor. a Film capacitor can cost 100 dollars unlike the 10 dollar cheap Bipolar electrolytic capacitor. Audio signals stop when they meet a Polarized capacitor so it cant be used as a bypass capacitor correctly. the Polar 220uf capacitor is just charging up, thats why there is a lot of noise. Lots of people just opt for the Regular cheap Electrolytic capacitors in the Cathode. Marfsgall once used 330uF and now they use 250uF but Marshall only changes values when they use parts that are in stock.
If you look closely at the start of the video, the big blue capacitor has in dents on both sides of the capacitor. the black capacitor only has an indent on the bottom side. Indents on both sides means its a Bipolar or NonPolar capacitor.
Agree with others... this was a great "new" format IMO for your vids with the informational -> repair -> demo.
Welcome back Brad! This world needs you brother:)
This video made me want to
1. Get myself a Fender amp (never owned one ever)
2. Get back to working on my myriad of unfinished amp and guitar projects
3. Get a Bigsby for my Tele
Stellar video, these are the kinds of videos that made me subscribe years ago. I often watch these while doing fretwork on guitars etc. Keep 'em coming, and thank you for the awesome content!
how can you not love brad,this was great it made me open up my best amp a 1972 guyatone reverb jazz,basically a fender super reverb.and i noticed my tech did what brad did put in great caps and good pots.i love old amps they just do all you need
Back to what you do best Brad. A thourghly watchable and educational video, well done.
Thanks for watching, Martin.
Dude...u still on your own?....if so, best dude decorator I've seen!
Brad you knocked this one out of the park. You are back and better than ever. I hope you continue putting out great content like this. We are pulling for you. Good luck.
Fantastic craftsmsnship in this amp and appreciated the deep dive you did in setting up the circuit
Thanks Lance. Glad you dug it.
Sweet sounding now i see why die hard electric guitar players love and want these old fender tweed amps. Learned something new today about circuits etc. I do love Hi Fi tube amps it warms up cds and gives life to vinyl! Thank you for posting!
This is one of the best amp projects that you have posted. The history and design era specific sleuthing to resolve the noise issues was so informative. It resolved questions Iv'e had with grounding design at Fender for years. Jennifer's comment is excellent historical input on who influenced the technical show at Fender. More please sir?
Excellent video, Brad. I’m glad you’re in a place where you can get top notch videos like this out to us! Great job dude, love it. 2020 has been such a bummer, I know you’re feeling it too and I just want you to know, whatever ideological differences we have, I really, really appreciate your knowledge on the subject of guitar electronics, which has turned out to be one of the most fulfilling parts of my life, thanks, in significant part to you and Uncle Doug for making it feel possible and straightforward. Keep it rockin’ man!
I wish I had a tenth of the knowledge you have. Great video. I've been watching for a few years and I'm glad you're back doing your thing.
The 6SC7GT (G lass T ube, don’t) bother with the metal tube versions these are generally microphonic) tube is a dual triode but only one cathode 8 pin tube similar to the 6SL7 with cathodes and an amplification of 70. Sovtek sells the Rusky equivalent of the GT version for $40. Leo in pursuit of clean switched to the 12AY7 with amplification factor of 40 for the later tweeds and used a negative feedback circuit some Ea Bassman (with 10meg resistor, Pro Amp 5 meg resistor) ahead of of the another 12AY7 and 2nd tube used as part of a localized negative feedback so it couldn’t be overdriven removed (5E5A pro gad the with the F series A models. My oldest son owns a “The Pro” which was a special order E circuit with the 6SC7 preamp tubes (it had factory black faux Alligator instead of tweed, he saw a 2nd one while in college working in a guitar store, and I saw one on eBay decades ago in white.
Great format on this video. I really like the fast-paced history segment with the background music. Great job putting this together, Brad. Thank you!
Great to see a classic Brad amp video again!
Dead quiet until you blow the windows out with an E chord.
Great, informative video Brad.. I enjoyed nerding out on this twin..
Hi Brad - great to see you back to doing your thing your way!
Ive missed these vids.
Great video, very interesting and informative.
Thank you!!
More to come! Stay tuned.
Great to see you working on amps again Brad! I have missed these videos! 😊🤟🏽 have an amazing day dude!
Great video Brad. This was a fun watch.
Thanks Dave. Glad you enjoyed it.
Another phenomenal video Brad! Thank you for taking the time and effort to produce such quality content, never has it ever not been enjoyable to watch these with my full undivided attention. This definitely takes priority over watching an hour long episode of whatever the heck TV shows you'd find on a streaming service.
That is a glowing compliment, Jonah. I appreciate you saying so.
My God ,Dude. You are an engineering marvel. I have been sending your vids to my Son ,who is an Engineering major in college. Thank you for all you do !
I wonder if the tech before had stuck the 6SN7 in the mix position of the tone stack with the 50uf bypass cap. The lower mu tube may have allowed the preamp to load more into the tone stack. Interesting to have tried that with the tube complement originally supplied. Lot of work involved there, and time and money. Working on these older is always a challenge considering that Fender prototyped on the fly during this time. He'd loan an amp out, and someone would bring it back with comment, and they'd make a change. Jim Marshall was the same in developing his amps. Artist input was what drove the innovations.
The 6SN7 is a different pinout than the 6SC7, so I don't think they were using it in the tone stack driver position. But yes, the supplied tubes does leave a bit of a mystery... The owner did say when he dropped the amp off that one channel seemed to not be working at all, so I assume that's because there was a 6SC7 in a socket re-wired for a 6SN7. I'm sure the amp would be more flexible with a different tube in the V1 or V2 position so that channel would respond differently, but in this case, I think re-wiring to factory spec was the right move because of the historical interest of the amp.
Nice tribute to Eddy too... and great to see you working on tubes again..
Nice work Brad, top notch!
I dig the vibe you hit in this video. Nice to see you have your Mojo back! What a great old amp!
Dude love the history section. You do a great job with it.
Glad you dug it. I'll try to do more in the future like this.
Great tutorial on vintage amp repair and troubleshooting, and amazing focus and determination.
You stayed with it until you got it right. Brad is back! and nice tip o the hat to EVH. Thanks
I think like a lot of other people, I've been reconnecting with Van Halen music since his death, and we really lost a luminary of massive importance. That much is clear.
Excellent video Brad for so many reasons... touche
Thanks, Russ! I appreciate you saying so.
Been watching the SRV aladdins cave vids.I been at this game a long time,lucky enough to meet Jim Brian May etc. But this pair of videos are no 1 to me, you are some player Mr Linzy.Salute
Thanks Brad. I really enjoyed the video; lots of great information & history in this one.
Glad you enjoyed it
Hey Brad,
Oddly enough, at the 5:50 mark of your video, you can see a "550" stamp on teh the right speakerl frame. The white "550" ink stamp was a code that went on all speakers in Valco amps back in the day. I don't know if Valco put the stamp on there, or if Jensen did, but it's factual, all Valco amps had a 550 speaker stamp, whether they were from Rola or Jensen. Leads me to think someone may have pulled these from a Valco amp to replace blown originals.
Valco definitely liked using P12P's. I've got 2 of them in my '63 Supro 1688T and one in my '54 Gretsch Electromatic.
@@RedGibsonsRock Their PM (alnico) speakers are great. I've stuck P15Ns in all my Thunderbolts. I started buying them up years ago in the used market for future replacement. The coils seem stout enough, but after all these years, they can be prone to develop mechanical problems-- vibrations, buzzing etc., as glues get more brittle and give up their bond.
Thanks, and upon review, you're right.
Bearing in mind that speaker technology has progressed in materials and industrial design over sixty years, it seems that later replacements, even of different manufacture, could only refine and improve on the sound originating from the original electronic 'recipe'.
Thanks Brad! This vid was truly entertaining. I was with you the whole time. I was glad when you decided to redo the heater wires and put a virtual tap to ground. I've had to replace jacks on a amp, which had no extra ground lugs. I wish I could show you a picture of the different style jacks I put in. The nuts are wide stainless steel, looks crome plated; decorative. I can't remember the name or where I got the first ones. I think they were given to me to try out. Bit it did make the amp look better and no noise.
Cool. I'd like to see those sometime.
Good work! The amp sounds great. I can imagine an old-timer blues player kicking back on his porch playing through that amp.
Great job of sleuthing those troubles away! Even though I have been in the electronics game for many moons I continue to learn new stuff from you. Keep it up.
Thanks for the comment. Glad you got something out of it.
What a great effin job on this video Brad. Front to back, great stuff. Classic Guitologist. Thank you dude.
Excellent video, Brad! You knocked it out of the park with this one!
I appreciate that! Thanks for saying so.
Brad, you're the man! MVP. Videos like this are "the heart," as they say.
Thanks for watching.
In 2003 I was in the shop picking my 68 twin and a fella walked in with his 52 twin. He was the original owner wanting to get it checked out before selling it. This gentleman was in his 80’s and used this amp all throughout his career as a steel player. I played it. It sounded like a toy compared to the high power twins. It broke up early but not as early as the 52 Deluxe I had the good fortune to play through. They both had similar tones. The twin was just a completely different animal compared to what I was used to. He was trying to get 6000 for it at the time. I wonder if he ever got the money he wanted? I enjoyed more so just meeting this man and having the connection with history.
Beautiful homage to EVH with 1984 in there. Cool vid and never realised the old Fender twin could get such a gritty sound!! Possibly why Eddie himself used Fender amps back stage in the warm up room!!
I'd forgotten about Eddie using Fenders for that. I think I read that in an old Guitar World interview back in the day?
Brad back to fixing old amps, life is good : )
These are my favorite vids you do,cheers
Glad to see you back! hope all is going well
I was working on a tweed bassman today. It had the same noise and microphonic issues. I thought about emailing you for a solution, but then I decided to man up. Perhaps subconsciously remembering what caused the noise issue with the non grounded input jacks from this video made the fix quick and easy. It wasn't acting like an asshole because of all of the ways it could, it was behaving exactly as it should with ungrounded multiple inputs.
Great great video! Really missed these! Thanks Brad!
Hey Brad!!!! I really enjoy your channel, tech chops, and musician chops. According to Aspen Pittman and certain associates of Leo Fender, Leo resisted attempts from his design engineers to stabilize the output of his amplifiers making them more linear and audiophile. Leo knew that his claim to fame was that when his amps were pushed to clipping by musicians of the day they cipped musically and this is what sold Fender amps. The first thing that Leo's design engineers did after the CBS acquisition and Leo's departure was to design Ultra Linear amps to stabilize the output of Fender amps like the silver face Ultra Linear Twin 135 Watt Amp. Leo hated this. Leo loved the fact that his amps clipped musically and was averse to the new 'audiophile' direction that his engineers pursued. JAFWIW
I was super happy to finally see an amp video again. Then I was even happier about the new format and production quality... then I saw Brad wearing a Tool shirt. All is right in the universe. Glad you're back, Brad.
Great video Brad. Always a fan of the epic marathon feature length videos.
More to come! I have another epic one in the can I just need to edit.
Thank you so much for another outstanding video, Brad!
Great job Brad! Thanks man for the lesson and the 1984 tribute!
Nice work, Brad. I really like the look of the blue Sozo caps all nicely aligned. Top class, mate.
Excellent deductions, my dear Jeremy!
Have you ever try to rectify the heater feed with a bridge and 2 300 mF capacitors? It quiet your back boise alot for about 2 dollars.
Good to see you back on amps brother. I'm hoping 2021 will see us ALL better and shaking off what can only be described as the bastard of years, 2020. Here for ya any time bro.
Very informative video, dude. Kudos on the troubleshooting.
this is why i subscribed..tx Brad!
That's awesome, and a cool coincidence. I recently scored a '57 Twin reissue on Reverb that had some heavy abuse, I've repaired the cabinet and just dropped it off yesterday to amp repair guy. I'm pretty excited to have one again, just a couple years ago I sold a '61 that I grew up with, and I was kind'a missing, even though it was such a beast :0)
Jeremy Brett ... One of my favorite Sherlock Holmes ... Good vid ''The Old Brad '' ... Welcome back ...
He WAS Holmes. He died playing that part. Pour his soul into it.
Good Job looks cleaner Glad you got rid of the OD and IC caps fixed the ground wires
Great to see another amp video and this is one is fantastic. Thanks
These days, a 1953 Twin would come with its own security guard. Even in that state, that's one highly desirable amp. Great to hear you playing again, too.
Thanks for sticking around. I know this was a long one.
This actual amp grew legs once from Tom Colvin's shop. Thankfully he was able figure out who would have access to get at it pretty quickly.
"Yeah? My amp has protection *and* a driver."
I have one of these Twin Amp's, mine dates to 1954 pots & speakers but the tube chart is long gone and mine is the next version with 12ay7's pre amp tubes, but still with only 4 control knobs- appears to be a mix of 5C and 5D circuit..
I have the same as yours. I put 12ax7's across the board. Amazing sounding amp
Wow! Set the wayback machine for 1953 Brad, Iv'e been Teleported back! Sounds killer and is dead quiet! Great work!
Brad, you are like the guitar gear whisperer I swear! Fantastic job dude!!👏👏🤘☝ Awesome video and great to see you back digging in an amp as it seems to be your passion. I want to thank you because after stumbling onto your channel a couple years back you really peaked my interest in the electronics side of gear. I'm happy to say as a result I just built my first pedal, a replica of an early Dallas Arbiter Silicon Fuzz Face circuit....and it works!! Lol!! I even built it using some nice transistor sockets so I can swap them out to try different ones easily. Stoked to build another one and even have my eye on an amp kit at the moment. Anyway thanks man, I really appreciate your channel and all you put into it!! Hope you're well and keep up the great work my friend!
what is that device called that's siting up high to the right (around 53:34) that reads voltage/ current/ power/ energy? It looks like it is attached to a variac, or can you buy them with that display? I have not seen anything like that with all those read outs. Is it something you buy separately and attach to a variac?
Having built an all octal amp in the past, they can be challenging preamp tubes to work with. Much of the used old stock are either microphonic, noisy, loose bases, etc. But man when you find a good one they sure are sweet sounding.
Yep! I agree. The pentode octals are particularly troublesome, but damn they can sound so good.
Dear Brad, thank you very much for your interesting and helpful videos! Be blessed, healthy and happy, and I wish the same for all the people around you, and all your UA-cam audience!
Greetings from Bulgaria! :-)
Thanks. I appreciate the support.
@@TheGuitologist You are welcome!
Fantastic segment/topic . Plenty of people on UA-cam show and play these thing. Giving us the TONES!!!! And that's all well and good. We all benefit watching those vids. But there's always more to the story. You going through, and giving us the history the way you do, is also just as important to the full story of these amps. Personally: I LOVE THIS SHIT, hahahah. Good to see you digging into your interests a little more. Great stuff, man!! Cheers from Akron, Ohio.
Thanks for that. I'm really glad you enjoyed this one. I put a lot of work into it.
Damn, I just bought that same style voltage display meter (DC) version recently. Good to know I think a little bit like the Guitologist!!
He's BACK!
Love those SoZo Blue caps... great in Fender style amps.
This was my second experience with them in an old Fender. I think they offer a high-end feel to the project. Anyone who opens the back to inspect it should be impressed with the component selection. I think it just shows someone competent cared about it.
Excellent amp demo my friend!!!👊☮❤
Great work on a super cool amp. I bet jumpering the channels would be even more fun!
Fantastic video. It's hard to believe that was an hour. Feels like fifteen minutes.
A Fender amp repair that would even make Uncle Doug jealous! Great video and amp.
I like to think Doug and Jack and the rest of his menagerie would approve.
@@TheGuitologist Oh, man. He's a Fender circuit fanboy for sure. I bet he's droolin' over this one. Or slobbering possibly.
Uncle Doug shotguns everything. He should stick to tv sets
Nice find on those jacks, Brad! 👍
Awesome video, awesome amp, awesome playing. Thanks!
That's a beauty! Well done man!
Sound is great with prs ❤️ amazing job dude !
Beautiful work!
Instead of obtaining an elevated voltage for lifting heater circuit virtual center tap from one of the tubes, it is customary to create that elevated point with a pair of resistors as a voltage divider right off the B+. I usually use a 1 meg ohm off the B+ and select the ground side resistor to get the voltage I want, which usually ends up being about 221K. From that junction, I also use another 1meg as a current limiter that go off to the center tap or virtual center tap. All that is needed to lift the heater circuit is a very very low current "electrostatic" offset voltage.
Great suggestion. I'm seeing some schematics using 330K to tap off the B+ for creation of such a node. I might try that sometime on a project. Increases the parts count though. That's one drawback I can see.
@@TheGuitologist Parts count of 3 resistors... a dollar ... plus being an isolated circuit, it is adjustable by simple part substitution to any voltage you want, and more important, your not tying any extra crap right to your audio circuit.
Like the album under the lamp.
I need a transistor for an old alamo amp.can u help me?
Itt 5210
"Check out the big brain on Brad!
Jules Winnfield
Nice repair! Great amp!!! ✌️
Man that amp has got mojo. You know why so many top players use them. I had a 25 watt version from ceriatone that I put in a 112 cabinet. I sold it a while ago , great amp that tweed circuit.
One of my first amp builds was a 5C5 'Pro' with the octal preamps. The natural roar as the amp goes (quite early) into overdrive is something that I haven't been able to recreate with pedals or other more modern circuits. Unfortunately the amp only gets up to maybe 18 watts so even with a 2-12 it struggles live without being mic'd well. But I'd love to build a 35-watt version, or look into the 5C8 Twin. That 6J5, though......
Yeah, honestly, none of the tweeds are all that loud by today's standards. I could increase the volume of this one by going 6L6GC and biasing to max. But it would stress the Jensen speakers needlessly I think. Anyone using this amp would probably mic it live anyway.
@@TheGuitologist But that octal preemp tone....
What a great amp adventure! Wish I could work on apps like I used to. Now I do is work on guitars. Anyway great video Brad
Hey dude. Good to see you.
@@TheGuitologist right back at you Brad. Here in La reporting from the Apocalypse. Still working never get sick. Just have to put up with a bunch of a-holes. So-so average day in La not much has changed.
That amp with humbuckers whooooo!!!!!! Excellent