Author Topic: as buffer? max the compression?  (Read 7333 times)

kvb

as buffer? max the compression?
« on: November 05, 2007, 07:36:54 AM »
I do not have a scope, so I can not answer these questions.
I have this circuit working on a bread-board in front of a distortion circuit.

Does this circuit compress a signal when it is set up as an inverting buffer?   220k to - in,  220k feedback R

Does the diode have something to do with the signal being inverted also?

both 5087s are set up similarly, except for the diode. So how can one of them be an inverted input?


Is there a way to maximize, or increase the compression? . . . within this circuit, or by using two in a row?
When I say compression, I mean limiting the signal to a certain size (amplitude)

kvb

Re: as buffer? max the compression?
« Reply #1 on: November 06, 2007, 03:11:44 PM »
Well, I put large caps on the last two transistors. 33u on the 2nd pnp and 100u on the output npn. this did something, but not too much.

I think I'm going to try making the output npn a darlington pair.

And/Or I'll turn the diode comp circuit from a buffer to a bit of a booster and blast a diode at the distortion circuit's input (like Joe Davisson's overdrives)

kvb

Re: as buffer? max the compression?
« Reply #2 on: November 07, 2007, 09:20:30 AM »
well, I did not try the above ideas yet.

I had been playing a bass through the circuit. I could not hear what the 33u cap was doing at the 2nd npn.  When I set up the circuit for guitar 'mode' and messed with the 33u cap, I noticed that it seems to take away some volume (tiny bit) when attached. maybe not the right thing for a pnp.

kvb

Re: as buffer? max the compression?
« Reply #3 on: November 08, 2007, 07:20:12 AM »
Hm. a darlington pair for the last transistor did not seem to work well. I've got this set up as a buffer, so maybe the darlington was blasting way too much negative feedback.