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tube amp repair

Discussion in 'Amps and Cabs [BG]' started by Speedy Claxton, Apr 29, 2009.


  1. okay so recently I acquired an old fender bassman 100 head for next to nothing in hopes of fixing it up. I took it to a local shop that does amp repairs and was told it's not even worth repairing because of the work that needs to be done, mind you they didn't even check the head yet. The guy I bought it from told me it needed a new power transformer and retube because his sons friend left it on all night without standby so it fried so thats all I thought was wrong with it. Now im bummed because I love these old heads for both guitar and bass and I have wanted one for quite some time but now dont really know what to do about it. What do you guys think?
     
  2. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    if you did get it for next to nothing, i think that you should fix it even if it does need a new tranny. and i would probably take somewhere else that actually likes them. IMO old tube bassman 100's are really cool amps.
     
  3. uaudio

    uaudio

    Apr 11, 2008
    Arizona
    "Not worth fixing" seems like a highly subjective thing to say...unless the cost of a functioning one is less than the replacement parts/labor.
     
  4. I would at least try to get the number of how much it would cost to fix.

    Him just saying its pointless to fix doesn't really help you, maybe its just lots of work for the tech and hes lazy.
     
  5. seamonkey

    seamonkey

    Aug 6, 2004
    You could learn to fix it yourself, especially if it's a hobby amp. There's probably more that needs to be fixed like caps. You could spend the money on a shop or spend the time learning. Vacuum tube repair isn't taught in trade schools anymore, so for most techs it's on the job, when an amp comes in. Pay them to learn or learn yourself.

    Here's one good site of some resources
    http://www.pmillett.com/technical_books_online.htm

    Danger High Voltage, and other safety issues like it is have a 2 prong cord and a polarity switch.
     
  6. gerryjazzman

    gerryjazzman Supporting Member

    Dec 31, 2006
    New Jersey
    How does the seller know exactly what is allegedly wrong with it (i.e. power transformer and retube)? Did he take it to a tech himself or is he knowledgeable in electronics repair? I find it hard to believe that leaving an amp on all night long idling would "fry it" or damage it to the extent that was indicated to you. If it IS damaged to that extent, something else happened, otherwise it may not be as bad as you think. How does it look visually? Does it look reasonably good cosmetically, any obvious teltale signs of overheating or other damage on the chassis itself, the tubes, caps, etc? Might have to look under the chassis as well to see if anything looks burnt or charred.

    I would try to find someone else to look at it before you write it off. As other have said, it's probably worth getting repaired.

    EDIT: Also look under the AMPS FAQ. There is a thread link there about learning amp repair.
     
  7. my advice would be to not bother to take it to that tech sounds like he wouldn't have done a good job anyway! A old amp is always worth reviving
     
  8. drboyd

    drboyd

    Apr 20, 2008
    "It's not even worth repairing" means either:

    • I get paid whether I work on your amp or not so I don't feel like doing it.
    • I don't have a flow chart for fixing it from the manufacturer.
    • We don't sell them, so I can't charge you for it while I send it out the back door to the factory pretending it's under warranty.
    • The sales guys would rather sell you a new one. I'll give you five bucks for this one and send it across town to an old guy who actually does know how to fix them, then put it on craigslist for $500.
    I've got a Fender Bassman 100 myself - and I just fixed it myself. It took several hours of studying the schematic and scratching my head, five minutes of taking the chassis out, and 30 seconds of soldering.
     
  9. Stumbo

    Stumbo Wherever you go, there you are. Supporting Member Commercial User

    Feb 11, 2008
    Intergalactic Mind Space CA
    Song Surgeon slow downer software- full 4 hour demo
    I got the following info from: http://www.talkbass.com/forum/showthread.php?p=7046092 Tube amp repair techs- recommendations/links. Maybe one of them is in your area or can recommend someone to you.

    Fl The Amp & Music Parlor, located in West Palm Beach,FL, specializes in restoring vintage tube amps of any sort. Established in 1994, we are a warranty service center for Fender and do non-warranty work on most boutique tube amps. We also assist the "do it yourself crowd" with their project amps and repairs when they run into issues. Check out our website at www.ampshopmusic.com or give us a call at 561-471-9441.

    FL Vintone Circuits - Your search for 'that tone' has ended! www.vintone.com West Palm Beach, Florida. (561) 881-5443 Doug Stalters E-mail : vintone@adelphia.net. Custom built amps, speaker cabs and replacement cabs. Accurate reproductions of classic tonal circuits in exotic hardwood cabs. 25 years of electronics and fine woodworking experience. I use only the finest materials that are available today. You provide a schematic and I will re-create it. Tell me your wants and I'll design it. Send me your chassis and speakers and I will send you back a combo that you will treasure for a lifetime. All cabs are crafted of the finest hardwoods with half blind dovetail joinery, Leather handles, stainless steel hardware and heirloom quality hand rubbed finishes. Contact me for info and I will E-mail you photos.

    FL Kelly Hundley, Frank's Electronics, 4127 Hwy 389, Panama City, Florida 32405, Phone (850) 872-0606, Fax (850) 872-9590. Frank's is an authorized service center for Crate, Ampeg, Marshall, Electro Voice, Korg Effects and Services most instrument/P.A. amplifiers. Kelly is also a guitar player with over 20yrs experience and uses Fender amps exclusively on stage.

    FL Paul Rixon - Robin Amplification - 1300 B Jensen Beach Blvd, Jensen Beach, Fla. 34957, Tel. 772-485-1099, e-mail robinamp@comcast.net Paul has a college degree in electronics. He has been playing guitar for over 35 years. He specializes in building his own line of amps. Point to point wiring, PCB boards are no problem. Specializes also in repair,modification and restoration of vintage tube equipment. Transistor work-just inquire about. Can also do lite luthier repair on guitars & basses, electric and acoustic. All guitar set-ups. References upon request.

    FL HI-TECH SERVICES is located in lakeland, plant city fl. The company has been in business for 15 years. They currently service all of the music shops in a 60+ square mile area. They are the warranty station for a number of factorys. The company motto is, "if it has wires...we can fix it". "We service tubes and solid state and smd amps, no problem". They are an AMPEG warranty station also.
    Hi Tech services, 3910 KIRKLAND RD. PLANT CITY FL. 33566, 863-644-0525
    Phil Dentler ke4bhe@gte.net

    FL Paul Markwalter, So Flo Tube Amps, Ft. Lauderdale, FL, 954-524-7169. We prefer to work on any tube gear, say before '85, however we love to bring old Gibsons, Valcos, Fenders, Danos back to life. We are also qualified for the Hoffman board Kit installations as we have built a number of Fender Tweed Knockoffs and back graded a few RI Bassman and 6G15 Reverbs. paul@soflotubeamps.com
    References

    FL Class A Electronics, LLC repairs all types of amplifiers and pro audio equipment. We specialize in vintage Fender amplifiers. We are a new business but our technicians are qualified and expeirenced. Class A is the repair center for 7 local music retailers and many of Tallahassee's musicians and sound industry professionals. We do warranty work for many major manufacturers. Located in Tallahassee inside Railroed Square. 850.224.7275 www.classaelectronics.com classaelectronics@hotmail.com We except drop-off and shipped service. please call for directions or RA#. Recommended by TB member Inverness: http://www.talkbass.com/forum/showpost.php?p=7029014&postcount=31

    FL Pro Audio Tech is a service company for solid state & tube amps, mixers, wireless systems, IEM, lighting systems, RF gear. FCC Technician License KI4JAY. Service center for many brands of gear. Visit our web site at: http://www.proaudiotech.net

    FL Rodgers Amplifiers, 3824 Exchange Ave. Naples Fl. 34104 Phone-239-649-8799 E-mail LJRODGERS@earthlink.net

     
  10. The person i bought it from works on tube amps as a hobby and claims to be very knowledgeable about tube heads and from talking to him sounds like he's the real deal he just didn't have time or money to get this one up and running i guess. I haven't yet pulled out the chassis to check it out but as soon as I do, I'll let you all know what i find. The tranny was already removed and looked pretty fried which I hope doesn't mean that the circuit board or anything else major is fried I really want to get this up and running.. :(

    thank you all for your help so far Im trying to contact the man I bought it from to see if maybe he could help me out if not I will definately check out those repair techs, thank you.
     
  11. WHHHHAAAAA...? "Not worth fixing"?? .:spit:. The guy was just not interested in working on it or he was intimidated by it. I say FIX IT!!! But yeah, take it somewhere else with a little more enthusiasm for vintage tube amps.
     
  12. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Birddog Bobby would kick that guy in the sack for saying that to you!
     
  13. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    the nice thing about the old fender amps is that there is nothing in them that can 'fry', i.e. no circuit boards, traces etc. at the very worst case, you'd need two trannys (very unlikely), some filter caps, a few resistors and coupling caps and new tubes. then she'll run another 40 years.
     
  14. bassfuser

    bassfuser

    Jul 16, 2008
    I used to work on amps and keyboards. The tech is probably just trying to be honest with you. For one thing, the transformer is probably going to cost at least a hundred bucks and maybe more. They probably charge $60.00/hour or more. In his mind, it's probably going to cost more than what you'd be willing to pay. You might ask him for an estimate anyway, but he'll probably have to charge you an hour labor or more even if the cost of the repair is so high that you wouldn't want to get it fixed.

    I would say that he should at least remove the chassis and try to determine the actual problem. He should be able to tell if it's the power transformer fairly quick. But as I said, he'll probably charge you for the bench test.

    They really aren't that hard to fix, but the power transformer or output transformer could run into some pretty big bucks if they are bad.
     
  15. jimbilly

    jimbilly

    Apr 19, 2006
    I was in a similar situation a few years ago, I bought a Bassman100 at a pawn shop for $180, but it would shut down after a short amount of play, and it had been modded to run EL34s. I decided that it would probably cost me more to get it sorted out than I could buy a good one for, so I took it back (7day $$ back at this pawn shop). I still think it could have easily set me back another $300-$400 in repairs. Since then, I found the coolest tech, via craigslist, he's a retired guy, does amp work as a hobby, and is very affordable. My point is: finding the right tech (if you can't become one yourself) can change your whole outlook on old tube amps. It's not easy to find the right tech, but they are out there.
    If the output tranny is fried, it could be a little too much to fix, those aren't really valuable amps, so I hope you're into it for next to nothing.
     
  16. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Depending on age, the most typical indication of an overheated Fender transformer is tar running out through the hole for the wires..... Newer ones don't do that though. And even leaking tar isn't proof its dead.

    You'd need to use an ohmmeter (and preferably a high voltage leakage tester) to check the transformer for gross faults.

    But, being left on is just plain not a good reason for failure..... it's actually easier on the power transformer than a few gigs.

    Now, if it was left on with no speaker connected for some reason, that could be different. That would explain the re-tube as well...... although most Fenders short the output with the speaker disconnected so as not to have "open output" issues.

    The amount of BS I've heard from techs, who didn't know I had designed the amp they were talking about, ................ well, let's just say that some techs have a very low level of understanding about electronics.......!

    You probably need to discover whether the power transformer is really kaput.... that makes a considerable dollar difference in repair cost, and might let you decide if it is reasonable to do , or not.
     
  17. Stumbo

    Stumbo Wherever you go, there you are. Supporting Member Commercial User

    Feb 11, 2008
    Intergalactic Mind Space CA
    Song Surgeon slow downer software- full 4 hour demo

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