Me and clipping stuff... again!

[mateusborges]

Hehe, I know... I know...

It's different this time I swear, I want to try different things, throw me some unusual clipping combos, even strange and odd ones, I have one last 2p6t switch here.

Cheers!

[iainpunk]

CA3019

they do sound good, if you can find them. its extremely mojo due to its package and rareness.

cheers

[Fancy Lime]

JFETs configured as constant current devices. Essentially anti-diodes in terms of use as distortion devices.

[mateusborges]

JFETs configured as constant current devices. Essentially anti-diodes in terms of use as distortion devices.

Cool! For what I've read it's basicaly G tied to S to one side and D to other side with another set the other way around, right?
Something like this?



Cheers!

[marcelomd]

Check the links by Jack:
http://www.muzique.com/lab/sat.htm
http://www.muzique.com/lab/sat2.htm
http://www.muzique.com/lab/tclip.htm
http://www.muzique.com/lab/zenmos.htm

[idy]

Great to visit the AMZ pages. "All" the ideas are there, quite a few I don't remember having read the first dozen times...in particular the separate clippers for high band/low band.

But those links don't include JFETS. There are circuits that use them...I know the Mad Professor Stone Grey Distortion...can't think of others. Stone Grey uses them with D and S connected and G the other side... I have never tested to confirm, but they say that they work as diodes like this. And I can't guess how they might differ from more readily available diodes.

[m4268588]

But,
You may be discouraged to boring results.

[antonis]

JFETs configured as constant current devices. Essentially anti-diodes in terms of use as distortion devices.

Cool! For what I've read it's basicaly G tied to S to one side and D to other side with another set the other way around, right?
Something like this?

Cheers!

https://www.diystompboxes.com/smfforum/index.php?topic=67974.0

[Fancy Lime]

JFETs configured as constant current devices. Essentially anti-diodes in terms of use as distortion devices.

Cool! For what I've read it's basicaly G tied to S to one side and D to other side with another set the other way around, right?
Something like this?

Cheers!

https://www.diystompboxes.com/smfforum/index.php?topic=67974.0

Sorry for the late reply. Yes, I was thinking of what the OP suggested in the thread that Antonis linked, not using JFETs as diodes. To make it work you would need to do this (from left to right after an amplification stage):
Series capacitor - d(q1) - s(q1) + g(q2) - series resistor - g(q1) + s(q2) - d(q2) - resistor to ground - series capacitor

However, the resistor values need to be chosen carefully so that the whole thing saturates at currents that correspond to useful clipping voltages. This depends on the properties of the JFETs, which are notoriously variable. It will be finicky to get working right at all and even if you succeed, it will sound no or not much different from the bog standard diodes to ground. You never see this sort of thing because it is gratuitously complicated, needlessly hard to design, and unnecessarily unpredictable. But you did ask for unusual, strange and odd, right? It would be doing something differently purely for the sake of doing it differently. Which, as far as I'm concerned is a totally valid motivation, at least for diy electronics.

Andy

P.s. as soon as I get my KiCad installation working again, I can post a schematic but like I said, it's not really a practical way of doing things, imo.

[amptramp]

If you want the hardest of hard clamping action, the following clamp circuit goes from full-on to full-off within millivolts:



When Vin goes above the level set by the 5.1K and 10K resistors, the op amp pulls down enough to hold Vout below that level.  The diode voltage is essentially divided by the gain of the op amp so the reaction is very abrupt.

There is a Spark Gap overdrive that uses a 6AL5 tube as the clipping diodes.  These normally act like an ideal diode with about 1000 ohms in series but in this design, they are operated at low heater voltage for softer clipping.  The build thread is here:

https://www.diystompboxes.com/smfforum/index.php?topic=89363.0

[iainpunk]

oh, reminds me of one of the first tube experiments i did using an EABC80 (6T8), which is a triode and 3 diodes, but 2 of the 3 diodes share their cathode with the triode, while the 3rd diode is fully independent.
iirc it sounded like a farty distortion/fuzz thing. nor very good, but i had no idea what parts of the circuit did what with the tone. i can probably do an infinitely better job these days.

ow, and if you want some really crazy clipping, try a PUT/Thyrisor oscillator, they change frequency with their input voltage. if you want i can draw up a chematic snippet with such a clipping set.

cheers