Crate Vintage Amplifier Repair: Re-cap, Re-Tube, Re-surrection! (AmpMechanic
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- Опубліковано 8 вер 2024
- There's nothing like tossing yourself into the fire to get going on something like guitar amplifier & radio repair. And that's exactly what I did in this, my first full-on amp repair job as a greenhorn amp mechanic. I made countless rookie mistakes and learned from everyone of them. But when it was over, this Crate Vintage Club 30 amp was ready to rock. So, join me on my maiden voyage and follow along as I re-cap, re-tube... and ultimately resurrect this amp from the dead.
In this video, I show you how I check the amplifier's bias (voltage, watts and current for each of its four output tubes). Here's a link to my shared spreadsheet of which you are free to make a copy:
docs.google.co...
Hi there AmpMechanic.
Today I bought a crate vintage club 50 in pretty knackered condition, so your vid is a godsend: like some online university course for valve amp repairers !
You may not have a massive online audience, but I'm certain that we few watchers truly appreciate the time and effort you've put into these videos.
Thanks so much, and I look forwards to your future uploads.
Hi @Digital Chris... wow! this comment really made my day. Thank you so much and glad that this video could be of some help to you! Good luck with that amp!
@@AmpMechanic Howdy. Where can I find that circuit diagram with specs?
Just bought a club 50 myself. 2x12 version.. 1st, why is it called a club 50, when it's a 200 W system??
Mine doesn't seem to be getting any power. Honestly think the repair is over my head unfortunately. Never messed With any tube power equipment. Wish u lived close. Where are you located by the way?
@@incredifunk it's 50w! If you don't know the basics of electronic kit repair, do NOT mess with valve stuff - there are fatal voltages in there!
So the fix was essentially one cap and 1 tube?
Perfect video... I'm working on a Crate Club60 right now, so this was inspirational. Thanks muchly!
appreciate that you’re new to this, learning, and just thinking out loud. be safe.
Holy smokes! I've just begun to gather the tools and equipment to repair amps and such. It is rare to catch a UA-cam channel that is just starting out like your's. A few months ago I bought an earth Amp head, MOD 440, for $30.00. 1975ish? And the Amp repair bug bit me hard. I've since been watching the same bunch of great guys on your channel list. Keep making videos! Anything Amp and hobby electronics related, and people will watch and subscribe. Build it and they will come!
Welcome to the club! I've got a bunch more videos coming. I've been busy using the summer to get some outside work done while the weather is good. But I'm about to head back into the lab and have several videos part way through production. Stay tuned!
i learned that the best way to work on this amp is to only remove the wood screws and leave the rest connected to the back panel, open the vent grate to disconnect the speakers (mark pos/neg ) or take a picture, disconnect the reverb tank and i added wire and put male speaker tabs on extended speaker wire for easy disconnect in the future
While trying to find the correct way to clean dust/dirt and junk off my Dell Laptop motherboard, I found your channel. I understand electronics and everything you did, long but got it.
My Grandad graduated from KU in 1932 with an electrical engineering degree, about the same year "Bell Telephone" invented the transistor. What was on his finals test to graduate.
It had to be all about tubes. Also, I was the idiot who climbed Microwave & TV towers and got paid for it. The FCC requires these towers, light bulbs changed, etc., a guy or someone told me that even with modern electronics, the most wattage to transmit to receive was 40 watts. The space shuttle has a radio to transmit a long distant, but uses tubes. I think my Grandad and you would have spent time. He got me onto chemistry and later mechanical. The later allowed this self taught farm guy to fix everything and read schematics. DC is easy and used voltage drop a lot. Please tell if isopropyl is best for cleaning the PC board!
Also, a neighbor who moved, had me fix a simple vehicle problem, but gave me a battery powered "Marshal" amp that clips on your belt. It creates sound like the full sized 1970 amp they sold for $420. That was a lot of money in 70, a used Buick or Marshal guitar amp.
Have you or a buddy ever heard of that? I thought is was a toy gimmick but no way! This 6" X 10" amp (Rough Size) kicks behind.
Either way, I enjoyed your clam explanation of how things work, I have the same DMM but a little dirtier. Going to watch more on your channel as I have time I should not have.
I ran equipment at work, I was not hired to do. It was heavy, stuck in the mud and jumping for 5 hours. I've had 5 back surgeries, last July 15th 2020. I went in for an L3-L2 fusion, Dr did the L3, L4, L5, S1 all over again. At 6'3" tall in a short world, it burns to learn forward for a few minutes. That life.
So having to fix a 3/4 year old Dell that kills the A/C Green LED as soon as plugged in. Big shoulders. I wish I was a janitor for 40 years, not to say that is easy, but dealing with the gifts God gave me. Imagine, millions who know nothing but smart phones, twitter, youtube, google and do not understand an analog clock. Sad! Enjoyed your videos, subscribed & liked! Old Man 62.
Wow. Great story and thanks for subscribing. Sorry I didn't respond on a more timely basis. I love being closer to the analog world and knowing what's really happening behind all that digital stuff. Always good to bump into a bird of the same feather!
This is so excellent. I just got one of these amps and this more in depth than I could ever need. Thanks!
Andrew.. really glad you found this to be useful. I have more videos coming... took a break over the summer because I'm building a table with my spare time and needed the outdoor weather for all the cutting, sanding, etc. But once I'm back indoors, I will be back in the lab! Thanks again for your compliment. Compliments like these make me want to do more!
Same
I have this amp, but the 50w version, this video it is so great and instructional I will share it with my amp tech and maybe make things easyer for him. Thanks David!
Vlad, thank you so much for the great compliment. I hope it helps your amp tech. I have not touched the 50W version myself. These are some rocking amps. But the physical design?!!!! OMG. What were they thinking?
Thanks for putting up the video. I've been acquiring 60's era test equipment and collecting technical books with the plan of rebuilding/building tube amps, so this was interesting.
Great to hear another one is joining the ranks. Keep us posted on how it goes!
Nice explanation. the only different that I see in the 50w version (the one that I have) is that the 50w has a jumper J03 instead of the resitor R43 and capacitor C29 and jumper J01 instead of in J02. As well diferent power supply. Giving higher V the one in the VC50. So we must consider it...Thanks
Excellent video Dave! I have the same amp in blackTolex. Super sweet amp.I learned they have a small cult following and forums for hot rodding and modding them. I have no reverb on mine, so I will check for 150 ohms at the reverb tank.Again, truly fine video. You are a great teacher. Thanks so much!
David V thanks so much for the kind words. Made my day! Good luck with your amp.
Dude, when can you please come back? No pressure, just briefly saw a new vid out but then it went away before I could catch it. Hope you are doing well and looking forward to your next. You are a great addition to this niche. Cheers!
Sorry about that! About to publish one and have another in the works. Thanks for pushing me!!!
AmpMechanic I'm not pushing you because I'm a kind hearted do gooder. I'm a selfish arsehole that is jonesing for your next vid. That's how good they are. Get to tubin! BTW, I have been jamming through the Eico 147A Signal Tracer for a while now and it's awesome. Changed the original 1.5 watt speaker to a 4" 30 watt Eminence. But let not your heart be troubled... no vintage gear were injured during this film.
Thanks for the compliment. I've been working on a better video setup (building) my own light panels and such. That's why the delay. There'll be a video on that too.
Fantastic video of care and logical showmanship, how to inspire others who are so inclined to go the path of learning the SAFE way. Safety first, second and third. Without safety, the is NO path forward, especially with electrical charges.
For almost forty yrs, often doing the 120v 15/20amp circuits, I've been "hit" a few times. Thank you for stressing some of the specific areas a newbie should be especially tack-on re specific good practice concepts. For now, key priorities must be to finish my home improvement permit. (I'll be back, when I get the final sign off) and hope to learn more from your channel, (hopefully) improve my just purchased "all tube Club 30 amp.The schematic I got is 2 part (VC3112) a pre-amp page and a Amp page. Hopefully that's correct. Thank you Dave!! generous one. BTW; From Starving Musicians in Santa Cruz. Kudos to the "kid" who played really great lead guitar to show me it could produce what I love to hear. Rock on at 75.
But really have moved more to the (softer?) sounds, ie Harp Twins and Mona-Lisa Twins, or so, so, many talented ladies of lead and harp-guitars. Rock and roll me sweet ladies, gifts from heaven, I'm sure. Take care. added; Difference; Keystone or Agilent
Oh man, I made a lot of those same mistakes on my first few projects, great video as always.
Thank you very much for the compliment. You can be assured that some of those mistakes won't get repeated as I refine my skills and my checklist.
I have a VC2110, single channel amp. This amp has to have the speaker removed to access the amp chassis. There are 2 screws on either side holding the baffle. Once it is pushed out the front the tubes are right there. This amp does not have the removable back.
as you stated these amps were biased to run hot. The solder on the tube sockets to the board can crack from the thermal heat which leads to problems. reflow with additional solder and you should be good to go. I changed the Cr from 120 to 150 ohms (2 el84s) which added a lot of head room, but still had a nice breakup. Replacing the 20 yr old filter caps took the hum out.
If you measured the cathode resistor you'd probably find it was closer to 63 due to your calculations. personally I would not buy a 5th or 6th matched tube since once the ones you are using have aged they are not going to match the spares. Overall nice video.
Thanks for the great compliment. Much appreciated and great point on the mismatch on aging tubes (although I think it's good to have the originally matched spares if you need them in a pinch).
I believe the vintage club series started in the early 2000's. I have the Crate V30H. Amazing head.
I'll be the heads are great! This one was a combo of course (a big cabinet to hold all kinds of heat)!
I think it was late 90’s like 97ish
Dave, well done on your first Amp rodeo! I found, and watched, your first video 5 days ago. I thought it was a good video. The next day I saw some old gear for sale in the local paper's classifieds. The add had been online 47 minutes. 12 bad pics of old dusty gear, bad lighting, couldn't really tell what it was but the price was too low not to go take a look. "5 bucks each, or 20 takes all of it." I'm still am having a hard time rapping my head around what I ended up bringing home. I am now the proud owner ooooof... Taking a deep breath. A Tektronix 317 Oscope, a sencore PS148A vector scope, a Philco 7070 RF signal gen., an Eico signal tracer 147A with the aliens invader eye!, a B&K 1077B TV Analyst, an NC 300 big ass transmitter, and a B+K 1640 power supply. So I got up early this morning and devowered the rest of your videos in one sitting. Thank you for sharing your knowledge! I learned alot and am looking forward to your next video.
Thank you so much for the great compliment. LOL on bringing home the old gear. Sounds exactly like what happens to me. Sometimes, these sellers just want to unload everything and there may be just one item you want but the seller makes you take all of it for one price. I have literally cut off all purchasing until I get through all the stuff I've collected and restore and/or sell it.
@@AmpMechanicVintage test gear acquisition can get addicting fast! But what an awesome way to learn about electronics. I mentioned the Eico 147A Signal tracer. The magic eye has addled my brain. What a cool little guitar amp it would make with a 4" 30 watt Eminence speaker and some slight circuit mods to bring up the output from 3 watts to 12 ~ 15 watts. Anyway check out magiceyetubes .com. Also, what is blog/forum for Tektronix scopes you mentioned in your video that helped you with your groovy optocoupler tester? Thanks!
Hi. Thanks for the video. Maybe a little long/slow in explanations ...
Anyway, there are other methods who are quite faster: one is with a Bias Master. You put the valves on a specific soquet connected to the Bias Master. I have one of those soquets mesuring also the plate voltage; this bias mesurer gives you the plate current that you must decide before. Some amps have a bias potentiometer to adjust this current.
Any way you should also check the plate resistor(s) before mesuring.
Fair criticism. Always looking to improve. When I did this video, the Bias Master didn't exist.
You might try ham radio. Absolutely no end to the things to make/modify in that hobby. Even RF amps and transceivers if you go whole hog.
Thanks Wade. Yes, I have a bunch of old tube radios here that are in need of TLC and I'll be turning my attention to them. Some have short wave like the Zenith Trans-Oceanic. I had an entire ham shack here at one point (it was given to me) and I was going to get that all up and running. But erecting a antennae was going to be a challenge and Covid hit and all and they stopped the in-person license tests. So, I paid it forward and gave the gift to someone else who could benefit from it immediately. I might circle back at some point.
Looking forward to your next video. Top notch channel. Hope all is well.
Thank you @FWR! Production has been slowed down by my efforts to upgrade my video and audio capabilities. I have a new camera that I'm working with. So, more videos will be coming this year! Appreciate the great compliment!
I have that same GE fan in the background.
I like doing everything vintage. I wanted a fan like that for blowing off solder smoke. It's overkill. The thing creates a hurricane.
I've got the Vintage Club 50 with one 15" speaker. It's a great amp when everything is working right but it can burn through tubes and caps in no time. I don't work on amps but I've been fortunate finding a tech who can do the job. I wouldn't think of taking it on the road without a back up. I think it's a good idea to put a big fan in back of the amp. The tubes mounted sideways and getting hot cannot be good for their lifespan. Relying on that little channel switching button can be precarious because it can easily get dirty and malfunction. You're much better off connecting the channel footswitch. My model takes castors well because the cabinet is deep and low enough that there is minimal risk of the amp tipping over. This can be a problem with some larger Fender combo amps. The metal grills on the top can get bent and damaged quite easily.
Thanks for this video. I have Crate VC30 too, my first tube amp, and have been wanting to do some work on it. This video helps.
Glad it could be of help!
@@AmpMechanic Hi. Nice video. I got one of these VC30's off ebay around 2004 or so. I was wondering if you think its possible to install a little fan inside the cabinet to help with the heat. Maybe even with its own toggle switch to turn it on/off manually. A fan like this one possibly? www.amazon.com/Ebmpapst-612NGHH-12VDC-0-25A-606025mm/dp/B07PR9G9JJ/ref=sr_1_106_sspa?dchild=1&keywords=mini+electronics+fan&qid=1603853835&sr=8-106-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzTjlJREVGOEc3SlpSJmVuY3J5cHRlZElkPUEwMjY2MTA5MkxQME9aMEtQMFQ0VSZlbmNyeXB0ZWRBZElkPUEwMjYyNDQ4M0pBVUZaUzhDS0g1TiZ3aWRnZXROYW1lPXNwX2J0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
First want to thank you for being so thorough on a pretty good amp. I was watching your video and setting up my Vintage 30 up for some testing and my Stand By Switch broke in the off position... Do you know what the replacement part might be and supplier? Too funny that it crapped out when I was trying to do preventative stuff.
thanks for the awesome info. great vid.
You're very welcome Thom!
70% bias is usually reserved for fixed biased amps. Cathode biased amps can be at 100% max dissipation.
Very nice detailed video, thanks.
Thank you for the very kind compliment!
I think it's better to have unbalanced tubes on each section, if the balanced you can get parasitic oscillation especially feedback circuits, so each bank of two shouldn't be balanced but not all 4 as a whole, so each pair is out of balance with each other but balance with the other set. So are balanced two set to the other two set, but individually sets not balanced each other in the set of two
Great vid, thanks for the info!
You're very welcome @RockR1... thanks so much for the great compliment!
Hey Amp Mechanic! Thanks for this video. I also have a Vintage club 30. It blew the doors off a crate voodoo 50 at the music store so I jumped on it. In looking in the back of the amp and having cleaned all the pots with DIOXIT D5 and all the "pops" and almost all the static is gone and volume has returned. Now...when I was first in there back of the cabinet looking at the board I notice that as I put my hand closer to the four red wires that run from each the four terminal white plastic plugs the hum got quite loud. was the circuit looking for a ground? Also when I start loosening the boxed screws certain ones would "static" are these conditions telling of a flaw? And lastly is cleaning the dust off of the tubes recommended? It seems that the heat would get held in by a coating of dust on the tubes. If so How do I clean? Thanks Buddy.
Is the spread sheet you mentioned still available???? My bad? I Have bought a Crate All tube C30 and U1252B Now retired use to work on residential and light Commercial 110/220 v electrical as General contractor in Calif for 50 yrs. Some very minor custom circuits. Thanks in advance. Willing to purchase.
Dave, great video! Lots of good information that I'm sure I will be using. I have a Club 50 with issues so I will be watching this a couple more times. Could you point me in direction of getting a schematic of these? Crate has been out of business for quite a few years and I can't locate anything online for purchase or download. Any help would be appreciated. I also watched your video on your repair area power setup. Nice setup.
Hey there. I have this exact amp the vintage club 30 (3112) and I am wondering how to convert it to the 220V input because i now live in Europe and I bought it in the US. I am not an engineer but obviously you discovered how to switch the voltage on it. Any help would be greatly appreciated.
Thanks in advance and great video!!
hello great video do you have any experience with crate SPA amps specific the crate spa2000 I have one that is stuck in protection mode and stays in that mode and experience you may be able to offer would be helpful thanks in advance
Put a fan behind those tubes
I have a TD 50c amp, and the volume just fades to nothing in about a second or two, after turning on.
Hey I need the number on that IC chip on that amplifier thank you I put an nte in it doesn't work right
I've got the Crate VC 50 head. Mine started doing the thing where I would hear static and the volume would go way down while playing my guitar and then would all of a sudden be at full volume and then drop and back and forth. Now I get no sound out of it at all. I had the tubes replaced a couple years ago and hadn't really played it much at all because of these volume issues. So I didn't think it was the tubes. Not sure what's going on with it. Trying to find an amp tech in my area because the clean channel on this thing sounds great. My dad has experience with electronics from when he was in the Navy, and after he got out when I was a kid, so we're going to take a look at it this coming weekend. Any advice on what you would look at first? I'm thinking those capacitors like you did on here. I've read some forums and people were talking about those, as well as issues with the jacks, especially the effects and footswitch jacks. Dad still has some of his old testing equipment like you have here, although not nearly as much of it as he used to. I might suggest he watch this video a bit too...
Anyhow thanks for the video.
Hey Doug.... though I don't know for sure, I suspect that the head won't have the sort of heat issues that the combo amp does. It's really hard to know without seeing the amp... but my gut tells me that if it started cutting out intermittently and then cut out altogether, that it might have been gradual progression of something like a capacitor going from bad to worse to just passing all DC. It's really hard to tell. I'm sure the VC 50 sounds amazing when its working properly. The best tool (and one that you can make pretty cheaply) is a signal tracer. A signal tracer makes it possible for you to check each step along the signal path to see where things go downhill. But if you're not sure what you're doing, then it might be best to take it to a tech. There's a lot of high voltage in that amp and one mistake could cost you or your Dad as much as your life. So please be careful. Let me know how it turns out.
@@AmpMechanic Thanks for the response and the advice! I think my dad and I will do a limited look over of things and if it's nothing obvious or within our abilities I will then take it to a tech if I can find one. It seems to be a dying art, at least around here... back in the day it was a lot easier to find someone who could work on these things.
I definitely appreciate the warning and will remind dad about the need for caution, especially because of the high voltages in these units. Gonna get him to check out your video as well, as you talked about some of that and I want to make sure it's front of mind.
Thanks again for your response! I really appreciate it! I will let you know if we figure anything out on it, or if we turned it over to a tech!
@@dougfa3515 Let me know how it goes. Be sure to download the schematic before you start working on it and if possible, use a local print shop (like Kinkos or Staples) to print it out on 11x17 paper (so it is enlarged). It may be multiple pages. The Crate schematics are very good with what voltages and oscilloscope wave forms you should be observing at various test points throughout the circuit (keep in mind the schematic is showing peak-to-peek values and you'll need to convert them to RMS). But you'll need a signal generator putting out a 1kHz signal at 1 volt RMS (if I'm not mistaken). The schematic tells you. If you don't have a signal generator, you can probably get by with a smartphone or tablet. The wave forms are not so important. You'll need a good real RMS DMM too. Where are you located? Worse comes to worse, if you really get desperate, maybe you can send it here. But that would the very last option.. basically a Hail Mary.
@@AmpMechanic Great advice, man. I never thought about enlarging the schematics... I've been trying to find one that's legible. But the Kinko's thing is a good idea... I can tell you've done this a few times... LOL
I'm just outside Richmond VA. You're in the Northeast, right? That could be an option... Dad and I will check out some basic things and then we'll see how that goes and figure out what the next step is if unsuccessful. Again, thanks for the advice!
@@dougfa3515 Boston.
i have a problem with the brother amp crate VC 50 its a fixed bias but its not adjustable , and the bias is not negative enough , it is -15 volt and should be-18 volt , how can i fix this ? a voltage double r , but how should i hook it up ?
Really helpful video, I have the same amp and I'm in the process of checking the voltages, putting new caps and the whole 9 yards. I was wondering if you could share the amp diagram with me, I'dd appreciate it a lot! :)
Hi John-Jacob... all I did was an image search on Google for the schematics (there are two pages). The actual model of the Vintage Club 30 is the VC-3112. So, you may have to search that. I just tried it and found this link which contains the two schematics; www.4tubes.com/SCHEMATICS/Music-amps/Crate/?C=N;O=D
where did you get capacitors from?
I just picked one of these up for super cheap! I cleaned up the sockets and will threw in some new tubes. One of the tubes seems to be running hotter than the others. How would you adjust the bias on a single tube on this amp?
Hi Daryl, did you buy matched tubes? I thought about modding the amp so that I could individually bias tubes. But then ditched the idea and left that one big ballast resistor in there. Would have been major surgery for limited gain over purchasing matching tubes.
AmpMechanic I’ve never had a fixed bias amp before so this is all new to me. Mine is making this hum. Not sure where it’s coming from but as it is now, it’s unrecordable. The large caps don’t seem to be bulging. New to this stuff and already scratching my head over it.
@@daryllamont9942 So, the tubes are matching or no? Matching doesn't mean same model. It means they were literally designated by the seller has have matching profiles (usually determined with a curve tracer).
AmpMechanic oh yes, sorry. Tubes are matching.
@@daryllamont9942 the caps do not need to be bulging for them to have gone bad. These amps run super hot (the designers push the tubes quite hard) and there the amp was not physically designed with tube ventilation in mind. So, over the years, all that heat can easily cause the dielectric to dry out thereby ruining the caps. You could test the caps in-circuit if you have an in-circuit cap tester and maybe identify which caps, if any, are bad. But with this amp, you still need to pull the circuit board to get to their leads (which you'd have to do anyway to desolder and replace them).
Do you think I could make a spreadsheet like your's for '70s solid-state power transistors using an arduino? Or is that just Excel?
I don't think it matters whether you do it in Google Spreadsheets or Excel. The spreadsheet functionality that I rely on is not very sophisticated (something any spreadsheet technology can handle). Hope that answers your question.
I have the VC30. I get a cackling type noise when switching to the clean channel and no sound from the clean channel. The dirty channel works fine. How can I fix that?
Disclaimer: DONT try this if you have not understood the precautions in this video, and know how to drain capacitors. Even an unplugged amp can give you a fatal shock.
Re-flow the solder on the foot switch pins on the circuit board. PITA to get it out. Don’t heat too hot nor too long. Use good solder and a magnifier.
Amen Ton7Tube. One cannot stress the precautions enough.
Stanley, this could be any number of issues that would be very difficult to diagnose without putting my hands on the actual amp (or "hand" because you never put two hands in there!).
Greetings Mr AmpMechanic. I have a Crate G40c xl amp that i acquired recently from a Goodwill auction. I was just wondering if you had any experience with this particular amp. It worked for a while when I first received it. Although the sound was fading in and out. And now for some reason I have no sound. After doing a bit of research I found many similar issues, all claiming to range from bad diodes in the rectifier, to bad caps on the power supply. I am very limited on my trouble shooting capabilities.
The easiest way, if you ask me, is to start with the input jack, "listen" for signal, and work your way through the circuit until you have signal loss. Sooner or later, you'll encounter the bad components.
Sounds like great advice. I really appreciate your feedback. Thanks@@DavidBerlind
On that g40c XL I would absolutely start by either cleaning or replacing your instrument inputs. The originals are very cheap and I had the same kind of issue from mine from them
@@incredifunk I will certainly give that a try. Much appreciated.
Hey I have a Crate vc30, how far are you from jersey?
I also have a crate vintage club 30 that is having issues. Volume cuts in and out. What are some possibilities that I can do before I send it to someone.
Volume cutting out can be an entire range of things. I'm guessing the issue is unpredictably intermittent or you wouldn't be asking since you'd have a better idea of the source of the problem if it was easily reproducible. If you don't have a lab full of diagnostic gear, you could start with a chopstick while feeding a signal into the amp with a poor man's signal generator (it's hard to feed a constant signal into the amp with your guitar while trying to do this) and then tap on components. For example, if you tap on the tubes, you might discover that you are able to toggle the issue on and off and then that could mean it's a tube or tube socket. Or, just pull the tubes, clean their pins with an emery cloth and clean the sockets with de-ox and see if that makes the problem go away. Also clean your jacks and pots. If that doesn't solve the problem, my focus would shift to some tests that may require a variety of test gear (signal tracer, oscilloscope, or a DMM that can measure in Hz), but the general idea is to start at the input with a signal generator feeding a 1 kHz signal into the amp and working your way through the signal path all the way to the speaker until you find a location where your measurement instrument starts to register the problem. If it's cutting out completely when it cuts out, you'll see a complete loss of the audio signal (Hz and AC will drop to zero). If the volume is diminishing significantly but you can still hear it, then your Hz might still be there but your amplitude (ac voltage) will show major fluctuations. A few things about the Vintage Club 30. The tubes are nearly impossible to get to when the chassis is in the amp. I have no idea what they were thinking when they did that. So, first, not easy to maintain. You basically have to pull the chassis to work on this amp. Second, when the tubes are way back in there like that with limited access to fresh air, it gets very hot in there (even with the ventilation they put into the amp). Second, Crate pushes the output tubes hard and runs these amps very hot. More than necessary as this is a Class AB amp. The tubes could easily be biased to idle. They're not. This exacerbates the aforementioned heat problem. Third, that amp runs on a printed circuit board and guess what HATES a lot of heat? Printed circuit boards. If you get a lot of intense heating and cooling, it stresses the solder joints on the board which in turn could cause them to crack. A cracked solder joint somewhere in the signal path could easily be the cause of this problem. As it swells and contracts in response to the heating and cooling, the signal may or may not be able to bridge the crack and voila, you have an intermittent problem like the one you describe.Good luck!
I apologize for taking so long to reply to this. Somehow missed it in my inbox. Volume cutting in or out can be so many things, it's hard to know. Since this amp is part solid-state (with a circuit board) and it runs extremely hot, one area of concern has to do with all the solder joints on that circuit board. The constant swings between very hot and cool (when it's off) can stress all the soldering and cause some to crack. Volume cutting in and out can sometimes be related to a cracked solder joint that is making a connection at one moment, but not at another. But the problem you describe can be related to SO many other things, so it's hard to say for sure.
03/03/2022,,I have the MesaBoogieDC3 & '71Fender TFL5005D head, getting dusty cause no doctors could fix them. Sweetwater in Ft.Wayne changed the speaker and power cord.in my DC3 for $400. 👁 No way in hell they will ever touch it again. dont know shtt
hello, I had a crate vc50 and changed the filter capacitors, then I got 50cycle hum on the clean channel...any ideas?
Hi Eirini, are you sure you got all the filter caps? There are so many in there. Have you tone-traced the circuit.. (checking the circuit for hum through each step)? What about any wires carrying AC? Are they twisted to cancel the noise?
Or the schematic