transistor amplifiers im special

[Nigel Goodwin]

so you've convinced me but how do i go about choosing the right opamp. i know how to set the gain its the ratio of the input and feed back resistors right?

Look at the link I posted right at the beginning of this thread - specifically designed for guitar.

 

[the cracken]

Look at the link I posted right at the beginning of this thread - specifically designed for guitar.

the reason why i wanted to know how they worked is so i can design circuits like this.
**broken link removed**
this is an effects circuit for a guitar!

 

[Nigel Goodwin]

What's the point?, there are hundreds already out there - why try and design a different one?.

That's also a pretty poor example with far too low an input impedance for a passive guitar.

It's just a very crude overdriven amplifier.

 

[the cracken]

What's the point?, there are hundreds already out there - why try and design a different one?.

That's also a pretty poor example with far too low an input impedance for a passive guitar.

It's just a very crude overdriven amplifier.

Because i want to experiment! iv already though of a variable overdrive circuit. i just added to a circuit that was already pretty simple. but it means that i can control the overdrive from complete clip to no clip and also change whether it symmetrical or asymmetrical!

i know that circuit wasn't the best example my circuit that i modified uses the old lm741. not sure what the input resistance is but the input resistor is 1M.

 

[Nigel Goodwin]

Because i want to experiment! iv already though of a variable overdrive circuit. i just added to a circuit that was already pretty simple. but it means that i can control the overdrive from complete clip to no clip and also change whether it symmetrical or asymmetrical!

Getting the sound you want is more about your guitar playing skills than a particular effect unit.

i know that circuit wasn't the best example my circuit that i modified uses the old lm741. not sure what the input resistance is but the input resistor is 1M.

Like I said right at the beginning, opamps are absolutely trivial to design with, the input impedance is normally equal to the resistor.

 

[audioguru]

There is an excellent detailed discussion about the old Fuzz Face circuit on the web. It changes its sounds depending on the volume of the signal.
At low levels its has no distortion and produces muffled sounds. At higher levels it produces asymmetrical even-order distortion. At very high levels then its produces even and odd harmonics distortion.

It used old germanium transistors that have not been made for about 30 years (I still have some) and modern silicon transistors produce a different sound.

 

[the cracken]

There is an excellent detailed discussion about the old Fuzz Face circuit on the web. It changes its sounds depending on the volume of the signal.
At low levels its has no distortion and produces muffled sounds. At higher levels it produces asymmetrical even-order distortion. At very high levels then its produces even and odd harmonics distortion.

It used old germanium transistors that have not been made for about 30 years (I still have some) and modern silicon transistors produce a different sound.

i found a good fuzzface circuit using germanium transistors and i have per-chased them off ebay. not the exact one but equivalent transistors. but ill see how it gos.

 

[ericgibbs]

hi craken,

Ref your PM regarding simple transistor biasing.

Unzip this file, it should explain why bias is required.

I dont reply to PM'd technical questions.