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03-02-2008, 01:36 AM
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#1 (permalink) |
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Junior Member
Join Date: Mar 2008
Posts: 1
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VS100 power amp stage clipping?
Hi all !
I have a VS100 halfstack and the clean channel just doesn't sound right - I put a scope on it and at the beginning of the power amp (R1) the signal looks clean and symmetrical, but at the output (R31) it clips quickly, and is asymmetrical. In other words the preamp is clean, even driven hot from my Les Paul, but the power amp is yucky yucky! I got this amp used and it looks like 2 of the power transistors were replaced but not the other two - could this cause my problem? Btw, there's about 30mv of noise on the power supply, but I doubt this is an issue... |
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03-03-2008, 04:12 PM
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#2 (permalink) |
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Member
Join Date: Jan 2008
Posts: 62
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Re: VS100 power amp stage clipping?
Different brands of semiconductors can vary a lot. Or, maybe one transistor is defective? I don't have a schematic for this one to help you further. I would scope each transistor and see if they are all doing the same thing. There are probably some .22 -.47 ohm (or somewere in there) 5-10 watt resistors near those transistors, sometimes they crack from all the heat.
Tim
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