I read a few comments here praising this circuit recently and as I have been on a bit of a JFET run lately I thought it sounded interesting to try. So I have drawn up a Vero layout for myself and left the transformer off. This pedal seems to use the same transformer as used in the Hudson Broadcast and in exactly the same way. As it is a 1:1 transformer the way it's used doesn't have any obvious audible effect as far as I can tell, although I'm absolutely no expert! However I have built the Broadcast with and without the transformer and for the life of me I hear not difference!
Anyway I felt it was worth trying. And it is, I guess. I have built a couple of brown Deluxes and compared mine to an original '62 which I helped restore for a friend, as well as working on a friend's '62 brown Super. At first I set the drain voltages on the JFETS to ~4.5V and the sound of the pedal reminded me vaguely of the brown Super. That brown Super is not exactly my favourite Fender amp! I much prefer the sound of the Deluxe, which has a LOT more midrange and smoother breakup. Referring to online demos my version seemed to sound much like theirs.
So then I just messed about tuning the JFETs by ear, and for me it started to sound better. Some of the voltages are a bit out of left field but they helped reduce some of the fizz and vagueness of the feel and sound. Of course every J201 is going to respond differently so I doubt your Soma 63 will sound exactly like mine at these drain voltages: Q1: 5V Q2: 1.25V Q3: 2.5V Q4: 2.5V. You may think that some of these drain voltages are too low - I do! - but the pedal definitely sounds better for my use like this. You can see where I have set the knobs in the pic below. Top left is Volume, top right Gain, lower left is Bass, lower right is Treble. I put the Presence on a trimmer inside and it's fine just left slightly below noon. The JFETs are Vishay/Silconix sourced from Small Bear many years ago.
I don't mind this pedal but I have others I much prefer. Through a brown Deluxe it sounds nothing like a brown Deluxe! But it has an interesting "old Fender" kinda sound. The low end can be way too prominent and I have noticed in demos online that the bass is at around 9.00, which is where I seem to like it.
It could well be that you have much better success than me with the Soma '63. Maybe the transformer is magical and smooths everything out in a miraculous way, but I doubt it! Not sure if it's a keeper but it does have a thing.
Anyway I felt it was worth trying. And it is, I guess. I have built a couple of brown Deluxes and compared mine to an original '62 which I helped restore for a friend, as well as working on a friend's '62 brown Super. At first I set the drain voltages on the JFETS to ~4.5V and the sound of the pedal reminded me vaguely of the brown Super. That brown Super is not exactly my favourite Fender amp! I much prefer the sound of the Deluxe, which has a LOT more midrange and smoother breakup. Referring to online demos my version seemed to sound much like theirs.
So then I just messed about tuning the JFETs by ear, and for me it started to sound better. Some of the voltages are a bit out of left field but they helped reduce some of the fizz and vagueness of the feel and sound. Of course every J201 is going to respond differently so I doubt your Soma 63 will sound exactly like mine at these drain voltages: Q1: 5V Q2: 1.25V Q3: 2.5V Q4: 2.5V. You may think that some of these drain voltages are too low - I do! - but the pedal definitely sounds better for my use like this. You can see where I have set the knobs in the pic below. Top left is Volume, top right Gain, lower left is Bass, lower right is Treble. I put the Presence on a trimmer inside and it's fine just left slightly below noon. The JFETs are Vishay/Silconix sourced from Small Bear many years ago.
I don't mind this pedal but I have others I much prefer. Through a brown Deluxe it sounds nothing like a brown Deluxe! But it has an interesting "old Fender" kinda sound. The low end can be way too prominent and I have noticed in demos online that the bass is at around 9.00, which is where I seem to like it.
It could well be that you have much better success than me with the Soma '63. Maybe the transformer is magical and smooths everything out in a miraculous way, but I doubt it! Not sure if it's a keeper but it does have a thing.
