Is this a good idea?

[ninjaaron]

I'm thinking of building a dirt pedal that uses an opamp to drive a clipping device of the users choice; ie: a JFET, a Si transistor, or a Ge transistor... something like that.

Is there any reason why that shouldn't be great fun and profit?

In related news, if I did try to use a Ge transistor (which I'm not all too sure about, since they are such a pain in the ass), is there any reason why it couldn't be PNP, even if I used NPN for the Si, and N channel for for the JFET? I mean, providing the voltages are biased correctly, the transistor doesn't care how the other transistors are wired, right?

(which begs the question... why are some people still building reverse polarity pedals? )

[Mark Hammer]

You mean like this golden oldie from the 90's?

[Gus]

Mark   I do not see anything in your post did you mean the Angry Beard 3 ?  J.H.

Other have built things with opamps to another device I have build a number of circuits like of like that and there was even a post not long ago at another site with a cool design.

[Mark Hammer]

Yes, the AB3 it is!  Good guess!

[CynicalMan]

I'm thinking of building a dirt pedal that uses an opamp to drive a clipping device of the users choice; ie: a JFET, a Si transistor, or a Ge transistor... something like that.

Is there any reason why that shouldn't be great fun and profit?

In related news, if I did try to use a Ge transistor (which I'm not all too sure about, since they are such a pain in the ass), is there any reason why it couldn't be PNP, even if I used NPN for the Si, and N channel for for the JFET? I mean, providing the voltages are biased correctly, the transistor doesn't care how the other transistors are wired, right?

(which begs the question... why are some people still building reverse polarity pedals? )

I'm actually working on an opamp to FET distortion circuit (partially inspired by the various tube emulations at ROG). More news on that soon.

And people still build reverse polarity pedals for fairydust vintage mojo.

[Vitrolin]

or maybe this one

[ninjaaron]

so, I take it that this is a good idea. I'm thinking of something opamp based that has all kinds of clipping options: diodes to ground, diodes in negative feedback loop, no diodes at all, then into a small selection of transistors or nothing (probably J201 and MPSA18. I just can't get into the Germanium hype). Top it off with a flat mids BMP tone control, and your good to go.

Only five things left to do:

1. Breadboard it
2. tweak it
3. build it
4.
5. Become obscenely wealthy

[CynicalMan]

I'm thinking of building a dirt pedal that uses an opamp to drive a clipping device of the users choice; ie: a JFET, a Si transistor, or a Ge transistor... something like that.

Is there any reason why that shouldn't be great fun and profit?

In related news, if I did try to use a Ge transistor (which I'm not all too sure about, since they are such a pain in the ass), is there any reason why it couldn't be PNP, even if I used NPN for the Si, and N channel for for the JFET? I mean, providing the voltages are biased correctly, the transistor doesn't care how the other transistors are wired, right?

(which begs the question... why are some people still building reverse polarity pedals? )

I'm actually working on an opamp to FET distortion circuit (partially inspired by the various tube emulations at ROG). More news on that soon.

And people still build reverse polarity pedals for fairydust vintage mojo.

Here it is!

http://www.diystompboxes.com/smfforum/index.php?topic=76823.msg628766#msg628766

Edit: OK, I guess it isn't an opamp but it uses the same concept.

[ninjaaron]

http://www.diystompboxes.com/smfforum/index.php?topic=76823.msg628766#msg628766

Edit: OK, I guess it isn't an opamp but it uses the same concept.

Looks cool. I bet you can get a shit-ton of gain out of the LM386. Does anyone know if you can use inverting feeback loops in the same way as an opamp as with the 386?

I actually have a couple sitting around here... maybe I should just test it myself...

[KorovaMilkBar]

so, I take it that this is a good idea. I'm thinking of something opamp based that has all kinds of clipping options: diodes to ground, diodes in negative feedback loop, no diodes at all, then into a small selection of transistors or nothing (probably J201 and MPSA18. I just can't get into the Germanium hype). Top it off with a flat mids BMP tone control, and your good to go.

Only five things left to do:

1. Breadboard it
2. tweak it
3. build it
4.
5. Become obscenely wealthy

i thought it was
1. collect underwear
2. ? ? ?
3. PROFIT!!!

ala south park