Interesting to me is that the video never concludes. It just sort of stops in mid info. Probably for the best.
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How do fix a Amp when you Do Not Know Whats Wrong
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"Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." Helmholtz
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Originally posted by Chuck H View PostInteresting to me is that the video never concludes. It just sort of stops in mid info. Probably for the best."In theory, there is no difference between theory and practice. In practice there is."
- Yogi Berra
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Lovely videos!
As to the amp, it doesn't sound like a power transformer problem, but talk of this and of those conductive boards in early Fenders that are spoken of rather more often than actually found in my experience, reminded me of a s/f Pro I had in that is the one of the few old Fenders I've ever had a real problem diagnosing (they aren't usually hard to fix, hence everyone here being frustrated with the various failures of this or that guru to fix it for you). The issue was a random but annoying clicking or spitting sound. It sounded like a bad filter cap arcing. It was time for a cap job anyway so I did one. No change. Heat and freezing and chopstick-tapping didn't locate the sound, though a firm tap just about anywhere would produce a click, sometimes. You could see the clicks on a scope, just about anywhere in the amp. So I suspected the power supply, but the clicks were definitely much weaker on the power supply side of the plate resistors. I took out the power tubes but the preamp still clicked. I lifted the cap that couples the preamp to the PI - it still generated clicks either with the power tubes out or with the preamp tubes out. Eventually I disconnected the heater supply and scoped it - there were the clicks - it was the heater supply winding in the power transformer, internal arcing I guess.
The owner kept telling me he suspected a conductive board after internet 'research'. It was very tempting to shotgun it with a new board but I'm glad I resisted.
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Originally posted by Alex R View Post...
. Eventually I disconnected the heater supply and scoped it - there were the clicks - it was the heater supply winding in the power transformer, internal arcing I guess..."In theory, there is no difference between theory and practice. In practice there is."
- Yogi Berra
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Originally posted by Alex R View PostLovely videos!
As to the amp, it doesn't sound like a power transformer problem, but talk of this and of those conductive boards in early Fenders that are spoken of rather more often than actually found in my experience, reminded me of a s/f Pro I had in that is the one of the few old Fenders I've ever had a real problem diagnosing (they aren't usually hard to fix, hence everyone here being frustrated with the various failures of this or that guru to fix it for you). The issue was a random but annoying clicking or spitting sound. It sounded like a bad filter cap arcing. It was time for a cap job anyway so I did one. No change. Heat and freezing and chopstick-tapping didn't locate the sound, though a firm tap just about anywhere would produce a click, sometimes. You could see the clicks on a scope, just about anywhere in the amp. So I suspected the power supply, but the clicks were definitely much weaker on the power supply side of the plate resistors. I took out the power tubes but the preamp still clicked. I lifted the cap that couples the preamp to the PI - it still generated clicks either with the power tubes out or with the preamp tubes out. Eventually I disconnected the heater supply and scoped it - there were the clicks - it was the heater supply winding in the power transformer, internal arcing I guess.
The owner kept telling me he suspected a conductive board after internet 'research'. It was very tempting to shotgun it with a new board but I'm glad I resisted.
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That one is staged Juan. Look close and you'll see. He touches the input jack to make the hum and his reaction is less instant than one would expect. He was focused on hearing the noise to know when to react. I've seen this vid discussed before.
I don't think GW is shameful bad. Certainly not up to par with the best on this forum. He made the mistake of publishing some goofy info that was clearly over his head. A lot goes over my head (but I'm not writing a book either). Overall I do think he's at least qualified to build and service vintage tube amps. And he does have a lot of peripheral info and experience on the classics that is probably useful in some ways. That said...
I have read other reports of people having trouble with him. From employees to other customers. Not so much incompetence as a shyster kind of mentality. I'll buy that. And regardless of his rap or claim I wouldn't do business with him on any level."Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." Helmholtz
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Originally posted by dumbassbob View PostI think I will ask about that to my Guru.too...
I wouldn't advise shipping the amp to have this fixed. I wouldn't accept an amp shipped to me for a tonal issue, it's too subjective and so too likely to end up with a dissatisfied customer. I would want to sit down with the amp and the customer and agree to what the problem was, then if I couldn't hear the problem I wouldn't accept the job. If he hasn't madeit sound the way you want it to sound after six attempts it is time to give up on him, seriously. You may think he's not done a good job for you but actually if you're not able to agree on what needs fixing then how can he be expected to fix it? These are not complicated amps and any reasonably competent tech will be able to get the thing back to stock for you. There's no mystery to the tone of an old Fender, it's a simple beast.
One little point - wouldn't any amp sound thin and harsh over the phone?
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Originally posted by Alex R View PostI think a bad power transformer is very unlikely to be causing harsh tone.
I wouldn't advise shipping the amp to have this fixed. I wouldn't accept an amp shipped to me for a tonal issue, it's too subjective and so too likely to end up with a dissatisfied customer. I would want to sit down with the amp and the customer and agree to what the problem was, then if I couldn't hear the problem I wouldn't accept the job. If he hasn't madeit sound the way you want it to sound after six attempts it is time to give up on him, seriously. You may think he's not done a good job for you but actually if you're not able to agree on what needs fixing then how can he be expected to fix it? These are not complicated amps and any reasonably competent tech will be able to get the thing back to stock for you. There's no mystery to the tone of an old Fender, it's a simple beast.
One little point - wouldn't any amp sound thin and harsh over the phone?
All of it.Juan Manuel Fahey
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