suggestions for a vero layout for an op-amp gain stage

[mordechai]

I'm building up a modified Red Llama circuit, and I'd like to "drive" it with an op-amp for an initial gain stage...something similar to how the TL072 in this circuit drives the discrete Mosfets here:

https://www.pedalpcb.com/docs/MOSFETDriver.pdf

I'm hoping that in doing this, the gain settings on the 4049UBE can be reduced and that noise/hiss will be reduced as well.  What's stopping me is that I really am having a hard time with the vero layout for the isolated TL072 stage in that Mosfet Driver circuit.  The ways of vero design are just not clicking with me, I've tried numerous times, and apart from the most basic things I'm just running into a wall on this. 

Can anybody suggest a vero layout that might enable me to build up the TL072 part of the circuit above, or a layout that might get me close that can be modified a bit to match it? 
 

[idy]

MXR micro amp would do it. The layout sites have them.
You think you need a buffer and a gain stage like the pedalpcb project?

[mordechai]

I am not sure.  I've built up variations on discrete mosfet devices before and understand how they work, and the concept of driving them with a jfet input makes sense to me...so the idea of driving a CMOS with an op-amp strikes me as similar in principle, but this is my first time attempting something like this.  On the Mosfet Driver project above, I can see how the first stage is acting as a buffer, but is that necessarily contributing to what that second stage is doing? 

I like the way the overall circuit works, so if that buffer stage is really contributing I would want to try to apply that to what I'm trying to do with the CMOS stage in my Llama variant project.  But if the TL072 stage would work just as well without the buffer I'd be fine with trying something else.  I was actually wondering if a Tubescreamer type device would work with the tone components removed from the second op-amp stage (since there are so many TS-type circuit layouts readily available).

[Mark Hammer]

The earliest incarnation of Craig Anderton's Tube Sound Fuzz did exactly that: op-amp driving 4049.  This was later paredn down to just the 4049 for both the 2nd version and the Red Llama.  The EHX Hot Tubes still kept the op-amp front end.  Personally, I preferred the 1st version of the TSF, since the op-amp stage allowed for pre-clip tone-shaping.  I used this for the 49-er, which is still posted around.

[idy]

Mad Professor Stone Grey distortion is another pedal like this combining opamp and inverters. But it uses clipping elements in the opamp also.

[mordechai]

Thanks for the tip on the Stone Grey distortion and the 49'er...which I can't believe I hadn't encountered before out here.  Mark, I really like how you used a spare op-amp for the frequency selection and boost, which I will definitely try at some point. 

The use of clippers in the feedback loop of the Stone Grey circuit is interesting -- so because this creates a clipped signal, the CMOS stages then don't have to be pushed as hard to do that, correct?  I would imagine this would be one way to cut down on the hissiness of the CMOS stages.  If I'm using a dual op amp for this, I would have to then ground pin 5 and connect pins 6 and 7 of the unused op amp to stabilize it, right?  (I have several TL072s and might as well use them).

If I have all of that right, then...what should I do to an existing vero layout for the MXR Microamp like this one to stabilize the un-used op-amp?  Please forgive what I am sure is a very basic question, but I have been having a great difficulty translating some straight-forward concepts onto vero layouts and am still trying to learn how to navigate that medium for building op-amp circuits.

[PRR]

> I have been having a great difficulty translating some straight-forward concepts onto vero layouts

If you don't grok Vero, don't use Vero.

The idea is fine: put parts N-S, use portions of E-W strips to interconnect.

But that's not a great fit to many circuits.

Instead use Holey-Board or Pad-Per-Hole. Put in your parts. Wire them up. Slightly more work but much easier to plan and implement, IMHO.