Single Stage VS multiple stage design ??

[SYK0T3K]

Hi Everyone!! I have this question that I could not find an answer for which is, what is the difference between a single-stage distortion pedal and a multi-stage (2-stage,3-stage,4-stage) distortion pedal, what does the other(2nd, 3rd,4th) transistors or op-amps do to the signal? Is it better? How to design a multistage pedal?

Note: I added one of the multistage schematic that I am trying to understand (GuildTM Foxey Lady)

[11-90-an]

Hello...

From your schematic, it has: An input stage, 1st distortion, 2nd distortion, a tone stack, and a recovery output stage. The big muff pi is similar to this... https://www.electrosmash.com/big-muff-pi-analysis
Apparently the first stage will 'soft clip' the signal, and the second stage 'hard-clips' it.

[SYK0T3K]

Hello...

From your schematic, it has: An input stage, 1st distortion, 2nd distortion, a tone stack, and a recovery output stage. The big muff pi is similar to this... https://www.electrosmash.com/big-muff-pi-analysis
Apparently the first stage will 'soft clip' the signal, and the second stage 'hard-clips' it.

Thank you for your reply! So I am assuming that there is some sort of switch to toggle between the soft clipping and the hard clipping stage separately, and wouldn't this distort the signal too much making it pass through the second and the third transistor? Do you have any idea how to design multistage gain or where I can learn this from ?? and what is the recovery output do?

Thank you again for replying, much appreciated !!

[11-90-an]

Ok, here's my take on explaining the big muff or any other similar multistage distortions...

Input stage - Boosts the signal, somewhat like a clean boost. The Sustain knob controls how much signal passes on to the next stages

1st/2nd/... clipping stages - Clip the signal coming from the Input stage. Since the diodes clip from the intensity of the guitar signal, the sustain can allow it to be slightly cleaner when turned all the way down.

Tone stack - Tone adjustment/ EQ. Loss of volume in this stage

Recovery/Output stage - Another signal booster to make up for the volume loss in the tone stack. Volume knob controls the volume going out of the pedal

As for the switch....
You can add one, if you want to.

Do you have any idea how to design multistage gain or where I can learn this from ??

You can start with the schematic you posted or the Big Muff 

[SYK0T3K]

Ok, here's my take on explaining the big muff or any other similar multistage distortions...

Input stage - Boosts the signal, somewhat like a clean boost. The Sustain knob controls how much signal passes on to the next stages

1st/2nd/... clipping stages - Clip the signal coming from the Input stage. Since the diodes clip from the intensity of the guitar signal, the sustain can allow it to be slightly cleaner when turned all the way down.

Tone stack - Tone adjustment/ EQ. Loss of volume in this stage

Recovery/Output stage - Another signal booster to make up for the volume loss in the tone stack. Volume knob controls the volume going out of the pedal

As for the switch....
You can add one, if you want to.

You can start with the schematic you posted or the Big Muff 

Thank you for the detailed explanation ! you really shined the light on things I couldn't see, thank you again for your help!

[antonis]

How to design a multistage pedal?

According to intended use..!!
(no more - no less..) 

[ElectricDruid]

How to design a multistage pedal?

Another answer to add to Antonis':

You design a multistage pedal by taking several smaller elements and joining them up. It's not done as one thing. It's a collection of stages that each add something extra, as 11-90-an described.

My own Hard Bargain distortion design is definitely multistage. I took a basic non-inverting op-amp stage, added a clipping stage, then added a Baxandall 'Mid' control stage, and then added a 'Tilt' tone control stage, and then I had an op-amp left over so I stuck an output buffer on the end too! While I had an overall concept, the design is several 'black boxes' joined together. You could take out one stage and replace it with a different circuit that does a similar function without changing much. In fact, during the development, that's exactly what I did, experimenting with different designs for the tone stages.

If you're aiming to design a multistage transistor design, have a look for some simple single transistor buffers, boosters/amps, tone circuits, distortion circuits, etc etc. Then you'll have a collection of elements you can start to mix and match to taste.

[antonis]

If you're aiming to design a multistage transistor design, have a look for some simple single transistor buffers, boosters/amps, tone circuits, distortion circuits, etc etc. Then you'll have a collection of elements you can start to mix and match to taste.

No see what you've done, Tom..
https://www.diystompboxes.com/smfforum/index.php?topic=124794.0

[ElectricDruid]

Sigh. Repeat thread.

[Ben N]

Walters? Is that you?

[anotherjim]

Yes, but...
Tone is the thing.
If 1st age distorts it creates new harmonics.
Add a 2nd stage and then those new harmonics get distorted and spawn more new harmonics.
There is a limit to how much you can do this before distorted distortion gets unpleasant. This might be why some players hate the BMP. A Tube Screamer is only a single stage.