bsiab2 different transistor

[bent]

Brown sound in a box 2

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=150&Itemid=178

It's say in the BILL OF MATERIALS TEXT : "Note:  Experiment or substitute J201 or other JFETS in all positions for slightly different sounds."

Just want to know if anybody try different JFET in different position....and if it does actually change the sound....

thanks

Bent

[mojotron]

There are a bunch of threads where people did just that. If you use the 'search' button you can see what people found out when they tried that. Or pm Ed G - I think he's tried every JFET known to man.

[powerplayj]

Try all 2N5457 for all positions or a MPF102 in Q3, Q5.

[bent]

thank you very mutch.....can't wait to try it... 

bent

[markm]

The 2N5457 and MPF102 have less gain and may "clean" up the circuit a bit.
I think they sound good however, I've never used them in a BSIAB.

[bent]

does the pin-out (dsg) need to be respected, or i can turn the transistor ...?

[petemoore]

  Get the pinout from a data sheet ... make sure D/S/G follows the schematic pinout.
  I use perf, and often 'invert' the S/G places on the board, and put the source in the middle of the 3 pin transistor socket.

[bent]

i want to try 2n5088 but i'm totally not certain of the result...cause it's said collector-emitter-base....
the 2n5088 is NPN amplifier transistor....do you think it will work...
if so...witch pin-out should be for matching DSG with CEB....

i'm the kind of guy who like to try several things...and when it's blow up in my face , i make my decision...

bent

[DuncanM]

i want to try 2n5088 but i'm totally not certain of the result...cause it's said collector-emitter-base....
the 2n5088 is NPN amplifier transistor....do you think it will work...
if so...witch pin-out should be for matching DSG with CEB....

i'm the kind of guy who like to try several things...and when it's blow up in my face , i make my decision...

bent

Try it by all means, but don't be surprised if it doesn't work... JFETs (like J201s) and BJTs (like 2n5088) work on different principals and I would think the biasing would be totally out of whack.
I wonder what BJTs would do in a Mu-Amp configuration? 

However, you might create something interesting by accident.....


But I doubt it.

[bent]

thank's for the advice....
i think ill stay with switching the j201 and 2n5457, will be safer... i don't want to redo the pcb ....

ill post my try when finish, tonight i will do some attempt....

bent

[markm]

I don't think it's possible for a BJT to work where a FET is supposed to be 

[amz-fx]

I wonder what BJTs would do in a Mu-Amp configuration?

Yes, you can do that...  there is a schematic of a version in my mini-booster newsletter.

The bottom transistor in the mini-booster config is where the gain comes from...   the top transistor makes very little difference.   Put a J201 on top and then switch the bottom one around to get different textures.

regards, Jack

[markm]

The bottom transistor in the mini-booster config is where the gain comes from...   the top transistor makes very little difference.   Put a J201 on top and then switch the bottom one around to get different textures.

regards, Jack

I used a 2N5457 for the bottom tranny on my mini booster, seemed to clean up a tad and wasn't as "middy'.
Very nice tone BTW!

[Xavier]

I used a mix of J201 and 2N5457 as adviced by Ed Guidry. This version has less gain than the all J201 version, but it was equivalent to lower the gain pot. The basic timbre was the same to my ears.