Chuck D. Bones
Circuit Wizard
Not to be flippant or anything, but give it a listen and see if even needs "improving." Any idea where the trimmers are set?
M800 Overdrive
- Thread starter music6000
- Start date
The Magic is also where you set the internal Tone Trimmer, it has a big impact on the pedal!
Chuck D. Bones
Circuit Wizard
I should have been more clear. I meant to say "at what % of rotation or resistance did you set the trimmers?" 4.5V is a starting point, but I'd expect Q2 and Q4 to be set higher. I really need to finish writing that JFET biasing article!
Chuck D. Bones
Circuit Wizard
The tone trimmer interacts with the Q6 trimmer, so every time you adjust one, you should see if the other one needs tweaking.
sticky1138
Well-known member
Just finished this build. I set the all the trimmers to 4.5V and the tone pot by ear, which ended up sounding best around 9.3V. It does that Marshall stack sound, but it's muffled, the EQ is not that responsive and it's very noisy with the gain past noon.
Not sure if it's the J201s I'm using or improper biasing, but it's pretty underwhelming so far.
Not sure if it's the J201s I'm using or improper biasing, but it's pretty underwhelming so far.
try the settings for the trimmers listed in the first post to see if that brings the pedal to life. note also that changing the j201s could make a big difference.
sticky1138
Well-known member
Just sat down with a looper pedal for 20 minutes and tested a bunch of combinations by ear. I was able to clear up the noise and got a lot more high-end clarity, but the distortion is nasty and gates quite a bit regardless of setting. The EQ is still ineffective, too. Probably going to swap the J201s when I can get my hands on some.
peccary
Well-known member
The SMD J201's are reliable and easy to find, and you can use these and some pin headers to install them thru-hole: https://www.pedalpcb.com/product/sot23adapter/
Might save you some time and headache down the line.
What you are describing is out of spec J201's like my first set!
Purchase a set of these pre soldered from PedalPCB and save yourself some heartache & you will get the pedal to fire up correctly.
sticky1138
Well-known member
Thanks, I'm definitely doing that once they come back in stock.What you are describing is out of spec J201's like my first set!
Purchase a set of these pre soldered from PedalPCB and save yourself some heartache & you will get the pedal to fire up correctly.
