TransFet distortion

[mac]

Based on this post I breadboarded the below circuit:

http://www.diystompboxes.com/smfforum/index.php?topic=60345.0



It is a prototype. Help and ideas welcome.

mac

[burnt fingers]

I don't think you need the JFET's in the second or third stages.  They are acting as buffers and I'm not sure what the benefit would be in the middle of the circiut.

Have you built it yet? 

Scott

[ambulancevoice]

I don't think you need the JFET's in the second or third stages.  They are acting as buffers and I'm not sure what the benefit would be in the middle of the circiut.

Have you built it yet? 

Scott

maybe there for more tone or drive?

[ambulancevoice]

are there 6.8k rheostats?

[GuitarLord5000]

I don't think you need the JFET's in the second or third stages.  They are acting as buffers and I'm not sure what the benefit would be in the middle of the circiut.

Have you built it yet? 

Scott

I believe that the original article explains this:
http://gabevee.tripod.com/sstubepre.html

So, mac.............
How does it sound?

[mac]

I don't think you need the JFET's in the second or third stages.  They are acting as buffers and I'm not sure what the benefit would be in the middle of the circiut.
 
Have you built it yet? 

maybe there for more tone or drive?

Well, the original article says that the pair acts like a "single" tubey device. Three stages producing tube-like harmonics was my approach.
The thing is on the breadboard, I have to experiment a little more. The results are promising.

are there 6.8k rheostats?

The 6.8k set Vc at near 4.5v with my fets. But with another fets the resistors may be different. While in the breadboard, one can experiment with fixed resistors to set the appropiate voltage at the collector. But when building, a trimmer is the way to go, unless a std resistor gives 4.5v or so.

Talking about voltages, I'm going to try 6-7v at the collectors. Also replacing the 470 with diodes. Since diodes have a lower resistance, maybe 100,  it will boost the gain.
Also, the big muff tone stack at the end, and a resistor or diode between the fet and the transistor.

As you can expect it has a lot of gain, too much for my taste. I prefer it at mid levels.
I'm going to experiment and try to find my mic to record some clip instead of trying to describe the sound

mac

[mac]

Yesterday I set the voltages to 6.7 at the collectors, and replaced the emiter resistor R10 in the second stage with a Ge diode.
The diode has a lower resistance, maybe 100R, so there is more gain. And the 6.7v changes the clipping pattern. It's an overdrive tending to distortion. Crispy sound, maybe the high Z of all stages, and touch sensitive. At max gain, I picked softer and got almost clean notes.
I wonder how Ge transistors may sound... 
I'll try some more and record a clip of the best setting.

mac

[mac]

Sound clip at:
http://guitarfxs.tripod.com/index.html
Transistors voltages at 6.6V or so. Drive at 75%.

mac

[snoof]

sounds very nice!