Lamb Chop (Way Huge Pork Loin) Clean "Buffer"

[MattG]

I was looking at the schematic for the PedalPCB Lamb Chop, which is based on the Way Huge Pork Loin. See also the Effects Layouts Spice Runner, which is based on the Way Huge Saucy Box. Internet hearsay suggests the Saucy Box is a simplified version of the Pork Loin, and a quick glance at the schematics suggests they certainly have some similarities.

The gist is basically two circuits, a clipping/overdrive circuit (bottom half) and what I think is essentially a buffer or preamp of sorts (top half). There is a clean blend that allows the clean and clipped circuits to be mixed to taste.

What I'm curious about is the circuit for the clean signal. Reading about this pedal on gear forums, someone suggested it's based on the Neve 1073 mic preamp. I don't know if that's true or not. But, based on the marketing and reviews and user testimony, it sounds like the intent is that the incoming signal is transparently preserved across that clean path (for later mixing-in with the wet signal). Transparently preserved signal sounds like another term for a buffer. And if's really just a buffer, or even a preamp of sorts with minimal tone-shaping, couldn't the same effect be achieved with far fewer components (say a single or dual opamp)?

So I'm curious if anyone has any insight on this circuit in general, specifically the clean signal path?

 

[t1redhands]

Yep, the "clean" path is the Neve 1073 preamp, or rather two of them in series (schematic)
I'm not sure what technical name this arrangement of transistors might have, but it's also very similar to the preamp found in the Univibe (schematic)
As far as achieving the goal of a "transparently preserved signal," the Pork Loin sure takes the maximalist approach. It would be interesting to see these circuits analyzed in SPICE to see just how "transparent" they are. Regardless, this circuit sounds pretty good, either solo or in a serial pair.

 

[drew.spriggs]

I was looking at the schematic for the PedalPCB Lamb Chop, which is based on the Way Huge Pork Loin. See also the Effects Layouts Spice Runner, which is based on the Way Huge Saucy Box. Internet hearsay suggests the Saucy Box is a simplified version of the Pork Loin, and a quick glance at the schematics suggests they certainly have some similarities.

The gist is basically two circuits, a clipping/overdrive circuit (bottom half) and what I think is essentially a buffer or preamp of sorts (top half). There is a clean blend that allows the clean and clipped circuits to be mixed to taste.

What I'm curious about is the circuit for the clean signal. Reading about this pedal on gear forums, someone suggested it's based on the Neve 1073 mic preamp. I don't know if that's true or not. But, based on the marketing and reviews and user testimony, it sounds like the intent is that the incoming signal is transparently preserved across that clean path (for later mixing-in with the wet signal). Transparently preserved signal sounds like another term for a buffer. And if's really just a buffer, or even a preamp of sorts with minimal tone-shaping, couldn't the same effect be achieved with far fewer components (say a single or dual opamp)?

So I'm curious if anyone has any insight on this circuit in general, specifically the clean signal path?

If it was to JUST buffer - absolutely. That's also what that MOSFET is doing right at the start.

I can guarantee there's a lot happening to the frequency response/harmonics from combining out of phase signals that go beyond just buffering though.