Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hi all,

Picked up a early 90s Peavey Audition 30 in good condition.

Wondering if anyone would ever use the headphone out? I've seen other older or cheap solid state amps which headphone outs but never used them.

Questions that occur to me are, does it matter what impedance the headphones are? Will I wreck my headphones ( and my hearing ) by driving the amp too hard? Can this be used as a line out for a recording? Or used to drive a speaker not headphones at an attenuated volume.

While I believe I know the answer to some of these questions and realise that some sort of speaker emulation will be needed( there are lots of options software or pedals these days) , I hoping that forum members can give some insights or more detailed response than what I have in my head.

https://www.thetubestore.com/lib/thetubestore/schematics/Peavey/Peavey-Audition30-Schematic.pdf (https://www.thetubestore.com/lib/thetubestore/schematics/Peavey/Peavey-Audition30-Schematic.pdf)

I had also though that I wouldn't use a Pre-Out and that It be simple to add a Pre-In in the same spot, however the schematic shows the Pre-Out comes after the TDA2040 so that's not an option. I had a look at a few other Peavey schematics and they tend to have a pre out driver/buffer and/or a recovery stage before the power amp.

Any ideas or suggestions on ways to mod the amp for the most useful or practical Line/Fx In/Out for this amp?

Cheers
MasterVolume

I would place the effect in/out between the Post Gain pot and C20.
It might be easiest to remove C20 and run 2 wires to the new jacks from there, place a C20 cap between the return jack and PCB. (Solder one leg to the jack and the other to the wire)

Most headphones will work some better than others. R34 reduces the volume for headphone out.
Obviously use common sense and turn the volume down if the level is higher than needed.
Yes you can use Headphone output to record but both channels will be mono. Suck it and see.

R31 & R32 forms a 10/1 divider for Preout which should have been labeled "Direct Out".
Whether you take a signal from R24 Post Gain or from Direct Out will make little difference as the TDA2040 will simply reproduce what is at its input.(give or take an electron)

As for FX;
Q, How do you intend to use an FX Loop?
In such a simple circuit there is little benefit.
In all my years of playing I've found they cause more problems than they solve. just put your FX in front.
Although they do come in handy when trying to fault find a circuit.

As for Mods;
If it was mine I would raise the value of R20 (220k) up to 1Meg it will likely make the tone controls more effective. Although it will make that more sensitive and at high volume it may introduce a bit more hiss. suck an see

I often use 2Meg in the type of tone circuit.
Phil.

Here's the owner's manual.
https://assets.peavey.com/literature/manuals/80300569.pdf (https://assets.peavey.com/literature/manuals/80300569.pdf)