Muff - all inverted transistors?

[Fedorov113]

How would sound a classic muff circuit, if you put all transistors inverted?

[R.G.]

No way to tell. It depends on the transistors; whether the base-emitter junctions fail under the applied voltage or not. Datasheets are little help in finding this out. Might work, might not. If it works, it may not work well as the reverse gain on bipolars is much smaller than the forward gain.

Also depends on the transistor pinout. EBC devices go into reverse transistor operation when inserted backwards. ECB transistors do not work well at all when inserted backwards.

[aron]

Fedorov113,

What is the reason for asking this? You have 2 questions and both of them are suspect to me.

[GiovannyS10]

Fedorov113 its depends of wich transistors you is using. See the datasheet and take your own answers. But normally the result is not good. One time one transistor mine burns (burns real, with smoke...) because i made a wrong solder. But i was trying to make a dimmer.

[nick d]

        As a betting man , I would give 10-1 against hearing anything , 100-1 it might sound awesome ! Give it a shot and beat the Bookie !

[teemuk]

Classic Muff? a.k.a.Big Muff...?

It's largely a design based on negative feedback. Assuming you get modest open loop gain from the common emitter gain stages the negative feedback will make the circuitry less dependent on "open loop" conditions; gains, exact bias points and device characteristics have lesser importance because circuit's operation is more tightly controlled by the feedback. It establishes gain, frequency response, clipping thresholds (via diodes), etc.

You could even substitute the BJTs with plain opamps and the circuit would work in practically same way regardless. Because feedback.

But throwing around "inverted" transistors will ensure mediocre open loop gain and the negative feedback has less chance to work the way its supposed to. So you turn the operation from VERY predictable into something totally random... depending on transistors you choose...Assuming the circuit even works at all with reversed transistors.

[Fedorov113]

aron,

Well, I have a small workshop, and I produce a Rat - Muff pedal. I've made 40 of this pedals, and everyone is super happy with them. However, when I posted this question yesterday, I've discovered, that all 4 transistors in all my pedals are actually reversed. I use kt3102 transistors. The muff sounds really great, but is quiter and has less gain than the normal one.

[R.G.]

So you have produced a happy accident! Enjoy it. 

[aron]

OK glad to know you are real and are just asking innocent questions. Thanks

[DDD]

Well, now it's a time to be happy with inverted KP303 FETs for BSiAB 

[Vitrolin]

        As a betting man , I would give 10-1 against hearing anything , 100-1 it might sound awesome ! Give it a shot and beat the Bookie !

seem like the time to pay has come...