easydrive voltages? Joe? anyone???

[b_rogers]

hey everyone..

.

ive got the easy drive on the breadboard and was wondering if the collector voltage should be half of the supply, or if this circuit is different.  heres the schemo:  http://www.diystompboxes.com/pedals/index2.html

ive tried the search function, but noone discusses proper voltages


it calls for a 68k, but with the mpsa18 im using i have to use a 2.2k to get close to 4.5v???

with a 68k i get like below 1 volt.

any ideas? im pretty sure i have everything correct...took it apart and redid it a few times to make sure.

it sounds great at 4.5v by the way, very impressed.

[b_rogers]

anybody? Joe D?

bump..

[petemoore]

  any ideas? im pretty sure i have everything correct...took it apart and redid it a few times to make sure.
  Me too. Mines on perf so I can't take it apart, it's just an OA with a 10k resistor, and a few connections...checks out perfect every which way except the output isn't biased at all.
  The EZ Drive bias's with the values shown. My guess is that there is still a mistake in our wiring, that has not been found, despite the numerous attempts.

[b_rogers]

i am going to try a few different trannies and see if that helps. it's not that it doesnt work with that value collector resistor, it just doesnt sound very good. when i bring the voltage up it getts more tubey and defined, way less sticky and staticky.

[Joe]

The collector should be between .7V and 1V if I remember correctly.

[b_rogers]

thanks for the info Joe..i think i have an error somewhere thats giving me the bad sounds.

i love all your circuits ive built by the way.

the vulcan and antiquity are 2 of the ones that made it from breadboard to a permanent fixture.

the cold cathode is my next audition.

thanks again

[Joe]

The CC is not a good circuit, which is why I removed it long ago. Your Easy Drive might need less than 68K, maybe 47K.

[b_rogers]

ok i wont bother with it then, thanks for the tip. i had a wiring error with the 220k divider that was messing up the sound. great circuit. sounds awesome with boost in front and the stupidly wonderful tone control before the vol.