Peavey Mod...Very nice pre.

I noticed that, too. I was hoping that MF was clearing out more of these.

The N8dy has nothing to do with the PV, it's transformerless, one AX7 gain stage, IC buffers, etc.. There are some online vendors still selling the PV TMP-1, but it looks like they want $229 for it. I wouldn't pay that unless you really want to modify instead of build. You could build the improved version of this from scratch for less.

Also, the PV output transformer sucks, and I never use it. The unbalanced output just sounds better.

Edit: I was too quick to blame the output transformer, since I assumed that was the only difference between the unbalanced and balanced output. Not so, see next post.

RE: MB1 variable gain mod. Courtesy of Rafafredd.

Raf - I hope you don't mind my linking to your image. That variable gain control is really cool and straight forward. Does R13, 10k pot, need to be revlog for normal clockwise operation? If this can be done with an easily obtainable pot, I definitely want to use this plan in the PV, instead of the stepped switch.

For anyone else who is interested, I started tracing out the stock TMP circuit and the component values are mostly the same as in the modified schemo. One thing I was miffed about (though I should expect it) was that 5% carbon film resistors were used throughout the signal path. They had to cut costs somewhere. Also, the 1/4" output does not seem to run through the 12AT7 CF stage at all. It is definitely taken directly off of the Level pot.

> Does R13, 10k pot, need to be revlog for normal clockwise operation?

Yes. But the gain range is only 20dB, you could get away with a 10K linear.

> One thing I was miffed about (though I should expect it) was that 5% carbon film resistors were used throughout the signal path.

What is wrong with that? Specially in a $99-$229 effects box? They are not exactly losing money at $229, if they can keep volume up, but it seems like a fair price for all that you get.

The only resistor I would like to see a metal resistor is the first plate. The only ones that might be better than 5% are the feedback resistors, and then only if you need matched-pair. For multiple individual mikes, 0.5dB tolerance is more than plenty.

Anyone has the Peavey TMP-1 mod schematics along with the original ?
Maybe any info on a Jensen input traffo that would fit ?
Thank you.
Regards,
Dimitrios

bluebird said:

I compared it to a Peavey TMP I worked over with the help of Bo Hanson (sp?) when we were over at the old forum.
I had not used the Peavey in a while and kind of forgot about it.

I was VERY impressed and wanted to share the circuit with you all.

This is the last picture I could find of it. This is compleatly different from the original schematic. It did not use a 12AU7 originally. Stock transformers were used:

Click to expand...

Hi Ian,
It's been a while since you posted this and the link may be obsolete. Is this schematic still available to download?
Thank you,
Donn