No Distortion from Supreaux

[gerkear]

I just finished building Supreaux from ROG on my breadboard and I adjusted the trim pots to copy the corresponding drain voltage given on the site (http://www.runoffgroove.com/supreaux.html).  I plugged it into my practice amp and it worked but I wasn’t getting any distortion.  It just sounded like a boosted clean sound.  (even when i adjusted the Tone pot)

Could this be from the J201’s and 2N5457 that I purchased from Mouser?  The part numbers I bought were:  
J201 - 512-J201
2N5457 - 512-2N5457
I also have this J-201 around - 781-J201

Thanks

[Lonestarjohnny]

If you have a DVM you need to check your transistor's voltage's and see if they compare to ROG's, if you'll post your voltage reading's here i'm sure someone will help you,
Johnny

[Fret Wire]

What JD said, check the gate and source voltage too. Nothing the matter with the  JFETS you ordered. The pinout may be different. Go back to Mouser, type in their part numbers, and look up the data sheet. It'll have the pinout right on top. Then compare to the layout and see if you have them in right. The same JFET can have different pinouts from company to company. Post all the values and we'll see.

[gerkear]

Q1:  S=0.4V  D=4.54V

Q2:  S=0.5V  D=4.44V

Q3:  S=0.55V  D=4.65V

Gate voltages were 0V

Hope this helps

I also checked the pin outs from the data sheets and they are all the same.

[Lonestarjohnny]

your voltage's look good, you may need to use an audio probe to find where your signal is stopping, sound's like maybe a cold solder joint, if you dont have a probe, go over to Paul's site, DIYGuitarist, he has 1 that you can build for cheap, and he also explain's how to use it.
Johnny

[Fret Wire]

They seem to be in order. Double check your wiring on the volume (gain) pot. Lug one goes to ground. Double check all resistor and cap values. The "n" designations sometimes are confusing when it comes to cap values, ex. 4n7=.0047uf. Here's a conversion chart for the "n" values.
http://www.justradios.com/uFnFpF.html

If not, we'll move on to some more debugging.

[gerkear]

I'll give em a try and report back tomorrow.  Thanks for all the help.

[aron]

Yeah it's gotta be some sort of wiring problem (which it usually is).

[Fret Wire]

I almost forgot. Here's a tip when you order JFET's. These part numbers you gave are correct.

J201 - 512-J201
2N5457 - 512-2N5457

But, if you add D74Z to the end, you'll see that they're still Fairchild, but are alot cheaper. They are packaged on a tape roll instead of loose. And the leads are pre-bent so they drop right in the straight-line sockets that we all use.

It's confusing to see one company show five different versions of the same tranny, but if you go all the way to the bottom of the data sheet you'll see that the extra letters designate the packaging. Same transistor.

[gerkear]

I built the audio probe and stepped through the circuit and didn’t find any bad connections.  When I plug the effect into a guitar and amp I hear sound but it is not distorted.  It just sounds like the signal is boosted.  Is it just for tube amps?  If I took a picture of the bread board would anyone be able to take a quick look?

thanks MUCH!

[Lonestarjohnny]

Did you go back through the circuit and check for an incorrect value or a a mistake in the wireing, like Fretwire Said ? if so and no problem's there then you audio probed the circuit, nodda, then check the Jfet's, if you can't test them, you could swap out some to see if you have a bad 1, I did find several while i was building my Emulator's that did not give enough gain, and i did find a couple that did not work, also found a couple with to much gain, so you could have a bad fet.
A picture is worth a thousand word's, Sometime's !   :wink:
Johnny