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Author Topic: Peavey Deuce VT  (Read 10568 times)

Enzo

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Re: Peavey Deuce VT
« Reply #15 on: July 13, 2013, 09:35:33 PM »
So it is in the power amp, or at least after the power amp jack.  You did plug the guitar into the power amp in jack, right?  That seems to feed directly into the PA, start looking.  Your phase inverter runs on +300 as well as a +15 for base bias.  We need to know if those voltages are clean, use a scope.

As to source of noise, main suspects are the semiconductors, the two transistors.  They should be replaced in pairs anyway.  The 65839 factory parts are long gone, but the equivalent is 2N3439 or MJE3439.  350v NPN transistor.


If we have not discussed it, on an amp of this age, your electrolytics are probably dried out.   I see three 25uf (or 22uf) in the phase inverter.

And if I really want to know wher the noise came from, I'd use a signal tracer.  Look up "signal tracer" and find a million examples.  Look at a few, they are all the same really.   Ignore the part where they add diodes, that is for RF.   The whole idea of one is it is a small amplifier itself, and we plug a probe into its input.   There is a cap in series with that input so we block any DC that gets probed.   I use a small practice amp for this.

Roly

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Re: Peavey Deuce VT
« Reply #16 on: July 14, 2013, 05:23:58 AM »
Computer "powered speakers" can also be used as a signal tracer.

This may sound like a dumb question, but the "hiss" you are talking about is like the steady sound of escaping air or steam?  We have had people refer to low frequency noises like 50/60Hz hum as "hiss" so we need to be sure we are talking about the same thing here.
If you say theory and practice don't agree you haven't applied enough theory.

memoryman

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Re: Peavey Deuce VT
« Reply #17 on: July 18, 2013, 10:47:39 PM »
I replaced the filter caps with F&T capacitors.I heard that they are made in Germany and are good quality without being too expensive.What is your take on a brand (and a source) for the rest of the electrolytics?

Roly

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Re: Peavey Deuce VT
« Reply #18 on: July 19, 2013, 11:31:17 AM »
You didn't answer the question;

Quote from: Roly
the "hiss" you are talking about is like the steady sound of escaping air or steam?

...and new electros won't cure hiss.

I use whatever my reputable suppliers (Jaycar, Altronics, WES, &c) stock.  When it comes to connectors one manufacturer stands out for genuine quality, Neutrik, but for run of the mill parts such as caps and resistors there seems to be little real difference worth chasing.
If you say theory and practice don't agree you haven't applied enough theory.

memoryman

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Re: Peavey Deuce VT
« Reply #19 on: July 19, 2013, 03:37:43 PM »
Yes it seems to be more of a hum.