PAL-800 question
- Thread starter djmiyta
- Start date
Elijah-Baley
Active member
You can swap them, the pinout should be the same, but this doesn't mean these transistors are the same.
2N5457 has less gain than J201.
2N5457 has less gain than J201.
It doesn't sound right unless J201's are used, trust me!
This is your best option:
Barry
Well-known member
Definitely agree with @music6000, you need J201's for this one
djmiyta
Well-known member
That's what I thought. Damn I just can't get any crunch outta this pedal. I have mmbf201's that I biased with a multimeter and then by ear all i get is barely a mild overdrive with all the pots dimed. i figure if I can bias the jfets then my trimmers are in range I've triple checked all the values especially r11 the 470 ohm resistor that will stop it from distorting and it's the right value. .So is everything else on the board and I got my mmbf201's from Mouser so I'd think they're legit , unfortunately , I'm unable to decipher the the data from my transistor checker to know if they're in spec or not guess I'll be biasing a shitload of em next time I feel like troubleshooting this one then
Side note I'm now down to my pal m-800, mesmerizer, slow gear ,Grand Orbiter and one more to get all my pedalpcb builds up and running. They're all so close cause they pass signal on and in by-pass just without the intended effect. Eventually I guess.
side note side note
I just made an Idiot effects Blower box what a nice creamy crunch I get from this one it's really smooth.
Side note I'm now down to my pal m-800, mesmerizer, slow gear ,Grand Orbiter and one more to get all my pedalpcb builds up and running. They're all so close cause they pass signal on and in by-pass just without the intended effect. Eventually I guess.
side note side note
I just made an Idiot effects Blower box what a nice creamy crunch I get from this one it's really smooth.
Show Good pictures of your Resistors & Components.
Are you getting around 9v on Q4 ???
djmiyta
Well-known member
I’ll double check Q4 just to be safe , but pretty positive it’s good .And pics of the board without the jfets to see the board better from different angles. Here’s to a better quicker and smarter set of eyes than mine. Cheers! and thank’s for taking a look
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Are all of them bias to 4.5v except Q4 which should be around 9v ?????
djmiyta
Well-known member
So many projects I get side tracked but yes all except q4. Then after I try biasing by ear and it just won't get into the crunch zone I'm gonna try some of my thru hole ones they test much higher then the mmbfJ201s i got from Mouser
djmiyta
Well-known member
I finally got back to this put in j201's biased it best I could and finally got some crunch out of it.
I was having some serious problems getting the trimmers to bias properly cause I used the shitty cheap ones . So I removed the shitty ones and put in some better ones I should have left it alone cause now one transistor just stays at 8 volts the trimmer does nothing . I think I screwed up a solder pad pulling the old ones out would be my guess since I changed nothing else. Maybe Ill try to find the problem but probably easier to start over with a new board.
I was having some serious problems getting the trimmers to bias properly cause I used the shitty cheap ones . So I removed the shitty ones and put in some better ones I should have left it alone cause now one transistor just stays at 8 volts the trimmer does nothing . I think I screwed up a solder pad pulling the old ones out would be my guess since I changed nothing else. Maybe Ill try to find the problem but probably easier to start over with a new board.
