Mod: Aria AEQ-1 Parametric EQ

[voidar]

This is quite some obscure pedal, and any information on it is hard to find.
I got mine off of eBay.

I've moded it for 18V operation, and it seems to help some in giving some more boost and headroom.
The pedal is based on a TL074 Op-amp, and you have controlls for level, frequency, q and gain.

Thing is, I can max out the level without getting any distortion from it, but when I get somewhat past 3:00 on gain with frequency set to mid (around 500Hz) it starts to fart out. 18V helped a bit, but I think there is something in the design hindering further clean boosting.

Any ideas?

[stm]

Do you have a schem by chance?

[voidar]

No. I would have to back-engineer.

[John Lyons]

Are you sure it isn't just the amp cliping with the that frequency boosted?
Is the 12:00 position flat or is flat with the gain knob all the way down?

John

[voidar]

I am pretty sure it is the amp is clipping. Not the amp driven with the level pot, but the amp driven with the EQ.
Specs say input shouldn't exceed +/- 15V. However the amp can operate at 18V.
I left a voltage divider in there, so it's running at about  17,5V. I thought that sounded better than 18V, but I am not sure, hehe. Francly, the headroom seems the same as when I ran the pedal at 15V earlier in the experiment.

I think the boost/cut is flat somewhere, as I remember cutting frequencies with it. Not sure if it is at 12:00, but could be.

But that could mean I can mod it for boost operation only, right, or at least shift the balance?

I'll try to draw up a schematic soon. It's not too complicated, and I don't have to include the on/off switching-/LED-circuits.