Modding the Orman Muff boost

[ljudsystem]

Hi guys!

I've been experimenting with Jack Orman's Muff Boost



I have two questions:

Does C1 and R1 form a high pass filter?

Is there a simple way to add a clean blend to this circuit like in Nick Greer's Green Gigant?

[antonis]

On behalf of Jack..
(without any written or verbal permission..)

1. Yes, they do...
By themselves, with a cut-off frequency of about 1.6Hz..
In combination R4, with a cut-off frequency of about 7Hz..
(assuming a h_FE=200 for Q1)
In combination with R4 AND R2, hmmmmm...
(I have to make some calculations about R1//βxR4//R2 equivalent resistor taking in mind the  - phase-reversed times Q1 gain -  Collector voltage..)

2. When you say "Clean" blend, do you mean unboosted signal blended with boosted one or boosted signal blended with clipped one, like in your scheme..??

[Mark Hammer]

There IS no clean blend in the Greer Green Giant.  What there is, instead, is a resistance in series with the clipping diodes to reduce the clipping down to insignificance (and inaudibility).

The relationship between the Muff Boost and Green Giant is analogous to that between the Tube Screamer (with clipping diodes in the feedback path) and the MXR Distortion + (whose clipping diodes go to ground).  The two approaches have slightly different tonaland dynamic qualities.  Can one do something in the MuffBoost that is similar to the Green Giant?  The simplest test is to lift the connection between DI/D2and C1/R1/R2.  In other words, insert an imaginary pot with infinite resistance between the diodes and their feedback path, similar to what the "Clean" pot does for the clipping pair in the Giant.

Insertion of our infinite-resistance pot will eliminate any effect the diodes have.  The question is whether it will completely eliminate any clipping.  The diodes in each circuit increase audible distortion, but single-transistor stages are entirely capable of clipping on their own, given the puny 9v supply we feed them.  Having heard neither of these two pedals, I can say with someconfidence that our suggested experiment will certainly reduce clipping, but I can't say whether it would result in NO audible clipping from either circuit.

The short answer to your question, though,is Yes.

[ljudsystem]

ok, thanks for the clarifications!

I'm gonna try the modds as soon as I get home.

I read the "read this before you post" text and realise I probably shouldn't have posted the schematics here 

[duck_arse]

post the schems of the circuits when you refer to them, otherwise we will all confuse about some or other point. and Jack is a member here, he would probably let you know if he didn't like seeing his circuit posted.