Looking for a circuit that most likely exists.

[Bill Mountain]

I have a Mesa Boogie Bottle Rocket that sound goods but is too cumbersome for my pedal board (power, size, and connection issues) and is falling apart.

I have been wanting to replace it for a while but I haven't found/built a suitable replacement.

It's basically multiple tube clipping stages into a modified FMV stack with some extra low pass filtering.

So the basic topology is clipper circut  -> FMV.

This should be easy to design but the possibilities are so vast I don't know where to begin.

Are there any circuits that come to mind with these building blocks that I could use as a starting point?

I'm not partial to any particular topology.  I'm just looking for circuit ideas to help me focus my efforts.

Thanks!

[avianoguitarist]

A few that come to mind immediately are:
--obviously the Dr. Boogie
--BSIAB
--Heavily modded Boss SD-1 (unless you're after a complete custom build)
--Ibanez Sonic Distortion clone--and modify with extra clipping diodes and switches.

Hope those get some ideas brewing

[slacker]

Marshall Guvnor

[Derringer]

I think it would be interesting to try a triode-to-fet conversion/emulation using the bottle rocket schematic and then tweak to taste if it comes out sounding close enough

[Bill Mountain]

Thanks for the suggestions.  They seem so obvious but like I said I was stunted by the possibilities.

I actually went back and studied some ROG projects and I currently in the process of bread boarding a Thor.  It seems highly tweakable for bass.

[Gus]

If the schematics I found on the web are correct It looks like it is all about the EQ then using tubes to me
You could use jfet opamps.  One dual might do it something like a 72 or 353

Opamps will allow you to more easily adjust the gain for the power supply voltage you will use. Lower gain for lower supply voltage for the right clipping

First opamp gain stage then the EQ gain volume
The  next three stages could be one opamp as a noniverting gain stage with a cap from out to + input across the feedback resistor as a low pass to sim the same response as the 330pf across the 100K at the 4th triode.  There is also the 47pf plate to grid at stage 4
You could also play with the EQ with a network like the RAT uses for the 2nd opamp - input to ground to sim the the two cathode RC time constants triode 2 and 4
Then do a cut and paste for the rest you could leave the stock value or scale the RC values

I don't think the 12ax7 tube output resistance will need to be added before the EQ but you can adjust things for that

It is often all about setting up the correct gain and EQ at and between stages

[Bill Mountain]

Yeah Gus, I think the EQ is quite important.  I've breadboarded it before and it excessively lossy by design (because of the high output from the gain stages).  I may want to use a basic active LPF at around 4.5k and then us just the tone stack from the Bottle Rocket.

The more I experiment the more I realize that most clipping sounds the same.  It's almost all about the equalization.

What I think helps this pedal is the higher headroom clipping.  I think I will try a few different opamp and BJT stages into some high voltage clipping diode arrangements.

The slight dirt and compression I get from this pedal really helps smooth out my tone and the EQ helps massage my mids.

Ofcourse I ran my Rat into my BMP last night with both at low-ish gain and I got some great dirt tones so maybe I could build like a 2-1 pedal with the Bottle Rocket tonestack.  Uggg the possibilities.

I also have Tube Sound Fuzz and BMP PCBs ready to be hacked into service.

[Derringer]

hmmm ...

how about:

Rat front end > adjustable gain stage (maybe fixed to a "low" gain sweet spot)> one BMP clipper stage > buffer > bottle rocket EQ > recovery stage (if necessary)