JHS Twin Twelve sounds too gated and sputtery

[GrooveChampion]

So I built it and I have to be honest about two things:

A. I am not sure if the JFETs are properly biased

B. I am using a 2n5457 instead of a J201 in Q1

[Frank_NH]

Using 2N5457s should be OK, though they will bias at a lower drain resistance than J201s.

For biasing the JFETs, measure the drain voltages and set them at around 5V (for a 9V supply voltage) using the trimmers.  Assuming the JFETs are OK that should give you a decent sound.

[Neil mcNasty]

The schematic this is based on is not the JHS pedal, but a Diy guys take on the Silvertone 1484's preamp (Which he named "De Stijl").
People have just assumed that this might be where JHS stole their circuit (says a lot about people's view of JHS) and I believe that this is not the case...
My bet is that the JHS Twin Twelve pedal is a Super Bolt (ROG Supreaux Deux) with the Baxandall Tonestack from the Twin Twelve, since the Super Bolt already sounds quite close to a Twin Twelve in the first place.

I have built this (The De Stijl circuit) before the layout appeared here, and I got the same result: gated and mis-biased.
Biasing it properly turned out to be impossible: since I hardly got any voltage difference on one of the transistors with 100K trimpots on the drain.
So I guess there is an error in the schematic that prevents it from biasing correctly...