Formula no 5 problems

[screamersusa]

I whipped up a formula no 5 on perf that has issues.
Now that it's trying to work, I like what I hear for old blues.

It has a nasty hum and the gain is way too high.
I had to sub J201 as it's all I had. I have lots of J201 and Mfp102's.
Every thing looks correct now, but I had an issue going from
vero to perf and missed a ground connection from ground/q3,q4 over to
Q1 Q2.  Also had to sub 2 1meg for the 2m2's.
Blown j201?
Any Ideas?

Will add sockets tonight, will mpf102 work in this thing?

I couldn't find one at GC to try much less anything else of quality.
They dont even stock their own deltalab box in store. All digital stuff and
they tried like hell to make me buy a tubescreamer or bogner pedal.
No blackstars in stock either

Thanks a million.

[electrosonic]

Can you provide a link to the schematic you are using?

Andrew.

[Ice-9]

I did the original RE on the Formula 5 a long time ago and the best sounding Jfets in there were the 2N5457 which is what the pedal also had in as standard, J201's sounded muddy when used. You should haveno problem with subbing the 2M2 with 2 x 1M resistors in series, I would recheck everything is correct first but it is quite high gain and hum will be there if its not in a shielded enclosure.

[screamersusa]

Ive got mfp102's in it for the moment. Had to change some caps to orange drops
(all I had) and it works better.
I verified I can pass clean signal through each mu amp stage alone.
Together its a buzzy mess.  Maybe its the dimmer in the work room?
Is there anyway to lower the gain on the second stage itself?

I built the one from Revolution, the roseblood11 layout.

[screamersusa]

Ok It seems there is a problem I cant find in the tone/gain circuit.
Everything looks good.
When the gain is turned down past mid way the hum goes WAY up.
Hum being louder than guitar signal. Using humbucker with parralel coil switch.
I am using a very clean 1 amp supply. I'll try a battery just for fun.

[Keppy]

The tone control's effect is reduced in this pedal as the gain is turned up. That might be why turning down the gain allows the hum to creep in. Of course, that just tells you that the hum is getting into the circuit before/at the tone control. Does the hum go away when you turn down your guitar's volume? In other words, have you made sure the hum is power supply/ground loop hum rather than amplified pickup noise?

I think the J201 has a much different Vgsoff than the 5457, which could affect performance here.

I've seen a schem with a 470pf tone capacitor mislabeled as 47p. This is the cap which connects to both the gain and tone pots. Check this value.

The schem I have only has one 2M2 resistor. Is yours different?

To reduce gain, try a 500k gain pot and change the resistor on lug 3 to 510k (470k is close enough). If you're using audio taper pots, the change should be small but noticeable.

Good luck!

[screamersusa]

OK Thanks for the reply.
I found the main hum, the GC deltalab box I was using to monitor with didn't play
nice with the formula on its own supply. Running them off the same supply got
rid of the bigger hum.
It still has a hum below 1/2 volume.
I may simply use it as part of a lead channel or mod it to become
a clean preamp stage for input to the rest of the beast I'm building
and use the second stage with a mosfet clipper as an alternate clean
lightly sparkled input.