Love Squeeze blend pot. Inverting or non-inverting?

[nonost]

I'm going to build a Love Squeeze comp with a blend pot.

I know that the second half of the opamp is a non-inverting configuration, but what about the first one?




Is it the kind of effect that inverts the phase?

Cheers!

[induction]

Short answer: non-inverting.

Longer answer:
Both op-amps are set up as non-inverting amplifiers. They have the signal fed to the non-inverting input and have the gain set with feedback voltage via the inverting input.

The second op-amp is not actually in the signal chain. It's the compression sidechain. The first op-amp provides the output to the output cap/volume pot, and also feeds the compression sidechain. When the input signal is large, the second op-amp feeds a voltage to Q1 that has the effect of reducing the gain of the first stage, thereby creating compression.

The circuit is an advancement of the Orange Squeezer topology. Compare the schematic to the OS schematic and read RG Keen's explanation for more info.

[nonost]

Thanks induction you are the man! :)

I've found a few options:

Split 'n' Blend from the main site




Simple Blend uploaded by Geiri



Blend Pedal uploaded by Chris




If I'm not wrong all of them do not invert the phase so they should work. Any preferences among the three of them?

Here the threads with the schematics for the second and third ones:

http://guitar-fx-layouts.42897.x6.nabble.com/Blend-Pedal-td16392.html

http://guitar-fx-layouts.42897.x6.nabble.com/Super-Simple-Blend-circuit-td6540.html

Cheers!

[induction]

I doubt you'll hear a noticeable difference. I tend to prefer op-amp buffers, but it looks like there's an error in the Blend Pedal biasing resistors, so I guess I'd suggest the Split 'n' Blend. The Simple Blend is probably fine too, since the Love Squeeze has a decent input impedance.

[nonost]

Thank you so much! I will try with the Split 'n' Blend first. I hope it'll work!

Cheers!

pd: you know a lot induction, but I've never come across a circuit of yours. Have you shared any original ideas that I have missed? I'm sure they would be great.

[induction]

Thanks for the compliments. I haven't been very active lately. I mostly just check in here to see if there are any debugging or theory questions I can help with. I have a 7-year old, a wife, a job, and various other hobbies that take up most of my time. Lately I spend most of my guitar time-budget on playing rather than building circuits.

I used to share my designs over at freestompboxes. For instance, there is the All Star Reverb. I've also designed a re-amping set up for my tube amp (a resistive dummy load feeding an inductive load emulation circuit into a small solid state amp that feeds the signal back into the cabinet so I can crank my amp late at night and not bother anybody), a bunch of pickup selector switch designs, a Ge-emulated Fuzz Face with piggy-backed Si transistors, some active EQ circuits, I can't remember all of it.

But like most of us, I mostly modify existing circuits to make them closer to what I want. I always design my own layouts, but I mostly don't share them because 1) they're customized for me, so people who want the stock circuits will be disappointed, and 2) more importantly, I use SMD in my layouts, and most vero builders are not so into that. In any case, I posted a few of them here. I have tons more, but I like to post a good write-up with them instead of just posting the veros, and I don't have that much time lately.

A few other things I've contributed to here are:
- a redesign of the ESR Graphic Fuzz to make it daisy-chainable. I never built it, but Rockett made a through-hole layout for it recently.
- a couple of multi-output power supplies. Rockett replaced the smd with through-hole components and posted a layout here.

The most recent design I did was for a workalike of the Wampler Plextortion. It's based on a verbal description Brian Wampler posted online (FSB, or maybe DIYSB). He's produced something like 6 different versions of that pedal, and I'm sure my version is pretty close to at least one of them. It's my favorite drive pedal lately.