[sdiy] RE: Re: [sdiy] Overdriving 4069UB

[Sean Costello]

Depends on the sound you want. I am pretty sure that modern Soldano-derived
tube amps have more than 3 stages of distortion - this would include Peavey
5150 and XXX, Mesa Boogie Single/Dual/Triple Rectifier, and the like. On the
other hand, you might consider some of these stages to be 1/2 stage, as the
preamp tubes will have asymmetrical clipping for the waveform, followed by
inversion, so it would take 2 stages to obtain symmetrical distortion. The
asymmetrical distortion/inversion will result in different time-variant
behavior, though.

A Big Muff has 2 distortion stages, which is rather unusual in fuzz boxes,
and it has a nice smooth sound. If you consider a Big Muff as used with a
tube amp, you probably have 4 or more stages (not much preamp distortion,
but some phase inverter distortion, and power tube distortion). For a Big
Muff to sound good, though, you want a fairly clean amp.

The Way Huge Red Llama used a 4049UBE for distortion, and only used 2 of the
6 inverters.

Personally, I think 3 stages of distortion is enough. It might be possible
to obtain very smooth sustained distortions with higher numbers of cascaded
stages of distortion, assuming low levels of distortion per stage, filtering
in each stage, and perhaps asymmetric distortion in some stages. My guess is
that this is used for both modern heavy metal amps (see above), as well as
getting certain super-smooth lead sounds typified by LA studio musicians.
However, the noise level will go up for analog systems, and the cost will go
up for digital systems.

Just my $0.01. Most of the above is my gut intuition, so I took off a penny.

Sean Costello

----- Original Message ----- 
From: "Paul Perry" <pfperry at melbpc.org.au>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, January 03, 2006 5:15 AM
Subject: Re: [sdiy] RE: Re: [sdiy] Overdriving 4069UB


> On the more general question of distortion stages in
> series, is there any opinion on how many stages there
> should be, and how much distortion there should be
> per stage? Is it not worth having more than 3 stages,
> for example?
> And what do the mathematicians think?
>
> paul perry melb australia