Graphite Distortion - Transistor Question

[Danbieranowski]

Socketed J201s (also tried 2n5457s) in place of the 2n3819s (had to adjust the pinout), but even with the transistors out of the sockets entirely the distortion seems to work fine and sounds like a good distortion. I can't really tell what the transistors are doing. It does seem to maybe tighten up the low end a little bit? And I know J201s are supposed to be gainy, but they don't seem to be adding any gain that I can readily recognize beyond maybe the slightest amount. I can see in the schematic that they are part of the Distortion stage, but beyond that I can't tell much of anything. The J201s are the PedalPCB SMD ones. Any ideas?

Here's the schematic:

 

[tcpoint]

The JFETs are being used as clippers (similar to a diode).

 

[Danbieranowski]

The JFETs are being used as clippers (similar to a diode).

How much should I expect to notice a difference in this case? Without them in place and with them in place seems relatively minimal. It's also worth noting, I used a TL071 instead of 051. From what I could tell, this shouldn't make a difference in regards to how the J201s affect the distortion, but I could be wrong there.

 

[tcpoint]

Measure the forward voltage. That will give you a ballpark idea. A curve tracer will give you a better a picture. I haven't ever measured those JFETs in that configuration. I might try that, tonight. My guess is that the type of JFET won't make a big difference (but I could be wrong).

 

[Danbieranowski]

Measure the forward voltage. That will give you a ballpark idea. A curve tracer will give you a better a picture. I haven't ever measured those JFETs in that configuration. I might try that, tonight. My guess is that the type of JFET won't make a big difference (but I could be wrong).

Thanks for your help on this. I’ve only tested it with a pretty high output set of pickups so I wonder if I’m just hitting it too hard from the front to hear the difference. I’ll test with some lower output single coils shortly.
On another note, what would be the benefit of clipping using transistors rather than diodes? Just trying to understand why the circuit would be designed one way over another.
Thanks again!