Deluxe Electric Mistress output phase issue

[Rodgre]

I have a vintage AC-powered Deluxe Electric Mistress and I recently tried it in stereo for the first time (dry to one amp and effect to another). When bypassed, everything sounds as it should. With effect engaged, the two outputs are out of phase with each other. Not just the wet signal, but the entire signal.

So I am thinking I need to put in a simple inverting buffer circuit on one of the outputs. My theory is a bit rusty so I thought I'd ask here. Is it as simple as building a single op-amp with no resistor in the feedback loop, using the inverting input, powering it from whatever bipolar power is on the board already? I haven't looked at the schematic just yet to see what voltage is on the board, but I assume there are other op-amps that need voltage already.

I should mention that I'm not sure which version I have yet. I haven't opened it up. I know it's original, not a reissue. It also is missing the "dot" on the i in Mistress, if that's a telltale sign of it's era to anyone. I heard these are kind of rare because of that misprint in the silkscreen.


EDIT: I just researched a bit and saw that the missing dot on the i might indicate that it's actually a 2000's reissue. That kind of surprises me, but it's on the internet, so it must be true!

This would be the schematic for the V4 version from early 2000s.

http://www.metzgerralf.de/elekt/stomp/mistress/images/1976-electric-mistress-v2-schematic_t.gif


Any thoughts? Thank you all!

Roger

[antonis]

Is it as simple as building a single op-amp with no resistor in the feedback loop, using the inverting input, powering it from whatever bipolar power is on the board already?

Not so simple, but still simple enough..

Inverting buffer MUST have Feedback/Gain resistors (of equal values) and its input impedance is set by the Gain resistor..
You can try an FET-input amp with 1M/1M resistors with non-inverting input biased at Ground (in case of symmetrical bipolar supply) via a 470k resistor..
It might be noisy..

[Rodgre]

Thank you!

I will breadboard that up tonight and give it a shot.

Roger