Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Travis8 on January 18, 2023, 04:51:59 am
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My laney VC30 sounds with a weird distorted tone.
I replace R57 and R58, also C31 becouse they look a little bit bad.
Some recommendations?
P2: 1.54v
P3: 177.6v
P5: 1.072v
P6: 150.5v
P9: 1.283v
P10: 151.4v
P13: 1.5v
P14: 194v
P27: 37.2v
P29: 57v
P30: 36.2v
P31: 237v
P32: 234v
P33: 4mV
P34:4mV
P47: 16.58v
P49:322v
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Is there a schematic to go with those numbers?
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This can help ?
(https://i.imgur.com/L3CkXLu.png)
(https://i.imgur.com/otCNiS8.jpg)
(https://i.imgur.com/Slk4pEu.png)
Franco
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First thing to do is to know is ; all tubes must be good.
Any work is a waste of time if you don't know about tubes.
And for a distorted tone, a tubes tester will not see anything, you have to replace the tubes to know.
Most of the time, with distorted tone, voltages are not the issue
Looking "bad" for a non -amp tech mean nothing. Show us picture.
On schematic R56 is a 7 watts resistor, it may look "bad " and it's not.
Last Kagliostro 's schematic at the bottom , in center
R58 and C31; I did not look at them
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I replace C31, R56 and R57 becouse they look dark brown like looks like something that dripped out of the capacitor...
Also I replace volume knob A1M, the amps sound good know but with low volume... even If i turn up at maximum its sound just more distorted but not louder...
Some recomendations??
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Some recomendations??
You did not read my first answer ? :BangHead:
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I replace all tubes for new ones...
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I replace all tubes for new ones...
Good to know,
Now you need to use some basic tools; scope and audio signal generator.
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I don't know you, me I'm not good enough to be able to fix this kind of problem without basic tools.
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Ok, no problem.
Told me wich tools and I get it, I wanna learn how to fix this amp..
all voltages are good, tubes are new... I wanna learn
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Ok, no problem.
Told me wich tools and I get it, I wanna learn how to fix this amp..
all voltages are good, tubes are new... I wanna learn
I'm sorry but I don't have enough time (nor the interest to be a teacher) to teach.
Maybe other members......
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Ok, anyone have some experiencie with this issue?
thanks
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Comparing your voltages to the schematic, some of your amp's voltages are as high as to 1.7x their spec values, others are nominal. And 'weird, distorted tone' is not very informative. But don't rush out and re-record everything. As Latole said,
Most of the time, with distorted tone, voltages are not the issue
I've only built a few amps and I'm quite new to this. People here have helped me a lot, but my questions were simple and about a single issue. No one could diagnose and repair your amp long-distance.
Places on the internet discuss electronics repair, especially of tube amp if you think you want to go that way. Try Uncle Doug's YouTube channel, he has a wealth of knowledge there and he's a great teacher. A couple of his videos should show you what's involved in diagnosing an amp. https://www.youtube.com/watch?v=R4hlopZvRD0 (https://www.youtube.com/watch?v=R4hlopZvRD0). Expect to read a lot of books and web articles!
My best advice to you would be to find a good amp tech. It will be way cheaper in the long run than doing it yourself. If you ask nicely, they may let you watch and ask questions. Our host has a listing of technicians here:
https://el34world.com/Forum/index.php?board=27.0 (https://el34world.com/Forum/index.php?board=27.0)
Good luck!
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The OT is bad.
Changue it and now its ok
Thanks guys