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Thread: Old tube amps - beyond econonical repair?

  1. #1
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    Old tube amps - beyond econonical repair?

    I frequently get PCB-based tube amps from the late 50s right through to more modern amps where the SRBP PCB has charred beyond reasonable repair, rendering it conductive over a wide area. Generally these are where EL84 sockets are mounted directly on the PCB - often having had a fair number of get-you-by repairs.

    Increasingly, the resale value of many of these amps is so low as to make repairs uneconomical from a commercial perspective. Either the board needs to be replaced with FR4 and repopulated, or a new circuit built up on tag board. Some amps are just too complicated; the 1980s Carlsbro 'Fat Boy' springs to mind. Even a simple amp such as a 70s Watkins Westminster needs a lot of time and parts to rebuild the circuit if the board is too far cooked. Add in a new set of tubes and warranty and it pretty soon gets to the point where it's not worth even quoting for the job. Very often these amps are 'finds' or have been bought very cheaply. The customer thinks because they bought it for nothing it can be fully restored for the same price. Or less.

    The problem is that many of these amps were made as cheaply as possible. I doubt that in 1970 WEM intended their amps to last 47 years and beyond, or that Bird made an amp in 1958 thinking it would 'need' to be maintained almost 60 years later. Maybe our customers are expecting too much.
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  2. #2
    Old Timer Leo_Gnardo's Avatar
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    Quote Originally Posted by Mick Bailey View Post
    The customer thinks because they bought it for nothing it can be fully restored for the same price. Or less. The problem is that many of these amps were made as cheaply as possible. I doubt that in 1970 WEM intended their amps to last 47 years and beyond, or that Bird made an amp in 1958 thinking it would 'need' to be maintained almost 60 years later. Maybe our customers are expecting too much.
    Maybe our customers are expecting too much. Sometimes that's exactly the case. Gear that was built to last maybe 5 years is still in circulation. To those who persist in such repairs I point out that at one time VW "bugs" and their variants were plentiful and cheap too. These days, not so much.

    And a quiet "thank you" to certain manufacturers who built their amps extra tough so they could still be successfully used 50, 60, 70 years later. I'm certain that would be regarded as an engineering folly in current times.
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  3. #3
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    I look at such lost cases as a potential for a "labor of love." I think if it has two good trannies with leads that can at least be brought to terminal strips or a turret board, and tube sockets that can be chassis-mounted, then it's a "parts platform." But it's likely never going to be restored to "glory," but instead, for several hundred, I can biuild a very simple circuit inside it using the tube complement it came with... I make no promise of anytime of completion, as these projects almost invariably come with some "engineering" challenges... for a hundred dollars in small parts, a hundred for the junk chassis, and my time, you could have a very nice handmade (moistly) amp that would almost certainly "survive" better, as there would not likely he the "collateral" damage of a charred PCB.

    There is ONE instance I know of personally where I wish I hadn't junked a blown amp... my friend blew the OT and a few other components in my Ampeg GU-12. I gutted the chassis for parts and threw all but the PT & cab away. Knowing what I know NOW, I would be able to make a turret board, following the original trace layout on two sides using wires. I <LOVED> the sound of that amp, and I had only paid $100 for it because it had loose connections that I was able to diagnose in the store. All that said, I know I'd never get more than $200 for it, but probably never would have sold it, either.

    Justin
    Last edited by Justin Thomas; 08-18-2017 at 03:28 PM.
    "When receiving a shock I emit a strange loud high pitched girlish squeak." - Alex R -
    "Sort of like not checking for toilet paper before taking a dump. ." - Chuck H -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

  4. #4
    Supporting Member Randall's Avatar
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    A customer brought a cool looking 50s Danelectro amp last year. He picked it up to flip it. It was all flown wiring, no board. The wiring was so dried and brittle that the insulation would fall away when I moved a wire to get a look at something. No way was I going to try to rebuild that amp for what he was hoping to pay. I backed away from that as quickly as possible. He then tried to sell it to me. Sorry, no.
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    It's weird, because it WAS working fine.....

  5. #5
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    The only "flippable" amps are the 1961 Vox AC30s that you buy at a yard sale for $10, that lived in a closet for their whole life, and just need a cap job & a three-prong. IOW, none. I mighta gave him $50 for that amp... given that it was true PTP I wouldn't be so concerned about the insulation, except for what rode along the chassis.

    But I know not everyone has the time and space for such projects, so I don't blame others for turning them down.

    Justin
    "When receiving a shock I emit a strange loud high pitched girlish squeak." - Alex R -
    "Sort of like not checking for toilet paper before taking a dump. ." - Chuck H -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

  6. #6
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    I have to make a living out of this, so commercially amps like this are not viable unless someone has an overriding sentimental interest or it has some previous ownership significance Some of these amps are perhaps interesting enough that I would be inclined to etch a new board or build a turret/tag board circuit if it was my own. I always think of equating the value and performance with a good used Blues or Pro Jr, though. Many sound like cardboard by comparison, even when fully restored.
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    Senior Member Enzo's Avatar
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    When I closed my shop, a large part of what went into the trash was the "Oh this will be great, all I have to do is put a little time into it" stuff.
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    Education is what you're left with after you have forgotten what you have learned.

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    Better Tone thru Mathematics bob p's Avatar
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    Quote Originally Posted by Enzo View Post
    When I closed my shop, a large part of what went into the trash was the "Oh this will be great, all I have to do is put a little time into it" stuff.
    I seriously need to do that kind of purge.
    "Stand back, I'm holding a calculator." - chinrest

  9. #9
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    One of the funniest clearouts I heard was a friend of mine whose father ran a garage for decades. When his father finally closed the doors, there were vast numbers of used twin filament stop/tail bulbs packed away in boxes - all of them had only one working filament. My friend asked why he'd kept them and the reply was that the other half was still good, so why throw them away? - they'd come in useful one day.

    Trouble is, that day never came.
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    Old Timer Tom Phillips's Avatar
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    I read a story once about a man who was cleaning out his deceased father's home Workshop. He found a small box labeled "pieces of string too short to be useful."
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  11. #11
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    Quote Originally Posted by Tom Phillips View Post
    a small box labeled "pieces of string too short to be useful."
    I remember reading that on the old Ampage "Bench Humor" section... throwback!
    In full disclosure I have to make a point to go through my wire box to avoid this problem...

    Justin
    "When receiving a shock I emit a strange loud high pitched girlish squeak." - Alex R -
    "Sort of like not checking for toilet paper before taking a dump. ." - Chuck H -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

  12. #12
    Supporting Member Jazz P Bass's Avatar
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    A stink bug crawled out of a Hartke tubular heat sink while I had my magnifier helmet on.

    Eeeek!

  13. #13
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    Only time I got call about a build ejecting smoke was from one of those... we hate those things. Every year, bazillions of them. But not ready to introduce more alien predators to get rid of them...

    Justin
    "When receiving a shock I emit a strange loud high pitched girlish squeak." - Alex R -
    "Sort of like not checking for toilet paper before taking a dump. ." - Chuck H -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

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