PAL-800 question

[djmiyta]

I know in some circuits J201 and 5457 are swap able would this be true for the PAL m-800 ? Can mmdf5457 be used instead of mmbf201?

 

[Elijah-Baley]

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.

 

[music6000]

I know in some circuits J201 and 5457 are swap able would this be true for the PAL m-800 ? Can mmdf5457 be used instead of mmbf201?

It doesn't sound right unless J201's are used, trust me!
This is your best option:

MMBFJ201 JFET (Pre-Soldered) - PedalPCB.com

JFET

www.pedalpcb.com

 

[Barry]

Definitely agree with @music6000, you need J201's for this one

 

[djmiyta]

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.

 

[music6000]

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.

Show Good pictures of your Resistors & Components.
Are you getting around 9v on Q4 ???

 

[djmiyta]

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

 

[music6000]

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

Are all of them bias to 4.5v except Q4 which should be around 9v ?????

 

[djmiyta]

Are all of them bias to 4.5v except Q4 which should be around 9v ?????

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