dynamically change transistors

[fuzzy645]

1.  Would it be possible to switch between different NPN transistors (such as 2N5089 and the 2N3904) in the Davisson Simiple / Easy overdrive circuit?   I'm thinking via way of a 3PDT switch (since the transistor has 3 leads).  The reason I ask is I'm thinking it would be cool to compare how these different transistors sound.

2.  If so, would any other component values in the circuit need to change when doing this?

3.  Along the same lines would it be possible to change which clipping diodes are used via way of a switch to change the characteristic of the distortion.

Thank you

[Earthscum]

1. Yes. I believe that beavisaudio has an example of this.
2. Try a socket. The difference you would get from the 2 trans you mentioned would be purely gain related. Try a darlington, 5089, and some kind of BC series. For some reason BCs have a metal can sound to them.
3. Diode clipper switching is so incredibly common that you should just search here for it. Most switching setups are pretty universal.
Lastly... Enjoy.

[fuzzy645]

1. Yes. I believe that beavisaudio has an example of this.
2. Try a socket. The difference you would get from the 2 trans you mentioned would be purely gain related. Try a darlington, 5089, and some kind of BC series. For some reason BCs have a metal can sound to them.
3. Diode clipper switching is so incredibly common that you should just search here for it. Most switching setups are pretty universal.
Lastly... Enjoy.

Thank you!!

It sounds that the diode switcher will be more useful.  I will follow your advise and search for some diode clipper mods.

Follow up question:   I then assume 1N914's (Si) will be interchangeable with 1N4001's (Si), 1N34's (Ge), 1N270's (Ge), with no other mods to the rest of the circuit, correct? 

[sixstringphil]

You'll have no problem interchanging those within the clipping section.

[therecordingart]

I'm actually working on a project right now that switches different clipping circuits. Once I'm done I'll post.

[fuzzy645]

I'm actually working on a project right now that switches different clipping circuits. Once I'm done I'll post.

Thanks...would appreciate that.

Would something like this work (i just tried to mod the schematic):

[therecordingart]

That's the general idea I had. Keep it simple.

[Fender3D]

I'm more on the flanger side than the fuzz one... 
but somebody should explain me why 1N400x should sound different from 1N914 

[egasimus]

Yes, that'll work, and you can also do asymmetrical clipping, and use LEDs as clipping diodes for a different effect.

AFAIK, different types of clipping diodes (1n4148/1n914 Si, 1n34/1n60 Ge, 1n400x power diodes, different LEDs) have a different sound mainly due to the different voltages at which they clip - more this than anything else...

[boogietone]

The knee of the diode will affect the tonal "quality." That is how sharp the clipping of the diode affects the frequency content of the clipped signal.

[PRR]

> explain me why 1N400x should sound different from 1N914 

Me too. They are the same part, except 1N400x is 10 times bigger. Both follow the same exponential curve for about any current we could care about. 1N400x will clip 0.06V lower, which is within usual gain-trim.

Ge may be different. LED may be softer (old-old ones sure were).

[oldschoolanalog]

I'm more on the flanger side than the fuzz one... 

Uh, yes. Me too.
But while we are at it; would somebody please explain/qualify what is meant by "the metal can sound". And please; no "mojo fueled" comments. Facts please.
Thanks!

[Taylor]

I'm more on the flanger side than the fuzz one... 

Uh, yes. Me too.
But while we are at it; would somebody please explain/qualify what is meant by "the metal can sound". And please; no "mojo fueled" comments. Facts please.
Thanks!

This clip easily shows the difference between the sound of metal can and plastic packages. You're welcome.

[Earthscum]

I don't know WHY BC's sound different, but they do. Some circuits you can't really tell a difference, and some are big enough to care about. I personally like the sound of a muff with a BC109 at the end. It just seems to have a slight bit more gain in the high-mids, about eh same area you would boost to get a tin can sound. That's the best I can explain it. Nothing magic, and not as different as a fet, but it is, like I said, different enough in some cases to care about. I've found that it's mostly at the end, where it has the most chance to color the final sound, especially if it's being driven hard.

Now, MY question... I've never tried any plastic package BC's... do they have the same character as the 107/8/9 metal cans?

[Earthscum]

This clip easily shows the difference between the sound of metal can and plastic packages. You're welcome.

+1   

[oldschoolanalog]

Thanks Mr. Livingston!
Now that's what I call an explanation...
Anybody else?

I don't know WHY BC's sound different, but they do. Some circuits you can't really tell a difference, and some are big enough to care about. I personally like the sound of a muff with a BC109 at the end. It just seems to have a slight bit more gain in the high-mids, about eh same area you would boost to get a tin can sound. That's the best I can explain it. Nothing magic, and not as different as a fet, but it is, like I said, different enough in some cases to care about. I've found that it's mostly at the end, where it has the most chance to color the final sound, especially if it's being driven hard.

Thank You!

[Fender3D]

lol
kinda big triode...   not duode...

[Taylor]

Less flippant: the title "dynamically change transistors" to me indicates swapping between two or more transistors based on playing dynamics, not just a switch. Perhaps this could be an interesting sound? A dynamic crossfade between two clipping circuits could potentially make for a more "touch-sensitive" feel (in an exaggerated way) - and we know how much guitarists like the touch sensitive thing.

[solderman]

3.  Along the same lines would it be possible to change which clipping diodes are used via way of a switch to change the characteristic of the distortion.

Thank you

Hi
I made a quick fix how to compare clipping diodes by using a IC socket here

http://solderman.fatabur.se/How_to.htm