Clipping FETs in a Tubescreamer. IRF510 or 2N7000?

[Mark Abbott]

Hi

During the COVID19 I have been going through old projects. I have been working on my Mad Bean Deadringer 2.

I originally built the Deadringer 2 using the IRF510 FETs (for clipping) but changed to the 2N7000 as the IRF510 wouldn’t fit in my enclosure. I have now a larger enclosure and can accommodate the IRF510, is it worth replacing the 2N7000 with the IRF510?

Is there a noticeable sonic difference?

During the whole process I decided to run the effect of 18v instead of 9v (via the Road Rage pcb). I think the Deadringer sounds more articulate with 18v, though I could be mistaken as the battery I was using initially was only good for 7v.

Regards

Mark

[niektb]

I think there might be difference because the Vth is probably different (haven't checked that in the datasheet though), not sure if it's for the good or the worse though 

[MikeA]

The IRF510 should give you a bit more feedback clipping than the 2N7000, the datasheets say the Vgs range is higher on the former.  I've used the 2N7000 but not the IRF510.  You can also increase clipping by reducing the supply voltage, your 18V supply gives you more clean headroom (higher input signal) before clipping commences, if all else is equal.

[Mark Abbott]

thanks for your replies. I appreciate you taking time to assist me.

Regards

Mark

[Elijah-Baley]

The IRF510 should give you a bit more feedback clipping than the 2N7000 [...]

Do you mean that IRF510 is more "distorted"?

I used a pair of IRF520 (with two germanium diodes) as hard clipping in a RAT. It sounds close to LED clipping, maybe more organic and natural.
I used 2N7000 in a OCD.

I have the same idea, to use a 2N7000 or BS170 instead of the IRF520 to save space. But I never tried. I hope those will not sound so different.

[MikeA]

Do you mean that IRF510 is more "distorted"?

Since the IRF510 voltage threshold is higher than the 2N7000, yes, it will sound more distorted when used in a feedback loop (soft clipping.)  When used for clipping to ground (hard clipping), it will clip less than a 2N7000, resulting in a louder and cleaner signal.  I find the clipping of a 2N7000 to be somewhere between a 1N4148 and an LED, so it makes sense that your IRF520 + Ge was close to LED clipping.   

[Mark Abbott]

In the Mad Bean Dead Ringer 2, the IRF510 was the best sounding clipping device. Quite a bit better than the 2N7000. This might not be true for all circuits, but it works well in the DR2.

Regards

Mark

[bluebunny]

@Mark: removed the spam post which you had replied to.