Post by JackPost by spudI have a blurry, useless, inaccurate paper copy from something called
analogman. If someone has a real copy with component values I'd really
appreciate it if you could contact me at the below address. I think
it's pretty similar to the Electro Harmonics PS-1. Thank you, s.
mrmasondjp
at
yahoo.com
Most schematics available on the web for this or the Mutron III envelope
filter are NOT going to be as easily readable as from something built in
the last couple of years. Got to remember these units were done before
CAD systems were generally available and were hand drawn. Analog Mike is
doing the best he can with what he's got. He's not a 'thing' but a real
person.
Well, a real person might have said, "sorry, the drawing I have is
shit, I can't sell this to anyone in clear conscience". It's a 12th
generation factory copy with no values on any part. It seems to show
the input and amp sections, power supply sec, then the control
sections but they are like three separate drawings. There's no way to
tell how it all goes together and no test voltages but who cares at
this point, let's forge ahead,..
Post by JackWhat kind of parts are you looking to replace?
dono, I just thought if I had the complete drawing I could figure that
out given enough time.
Post by JackThe op amps are/were
standard Motorola old ones, circa mid 1970's. If you can read the color
codes on the resistors (they were standard carbon resistors), that will
help. I never kept the schematic in my head, but could probably trace it
out if I had the unit in my hands. Oh yeah - don't try and put in a new,
super-duper spec'd op amp - the extended frequency response won't help
any, and may well cause more problems than it'll help.
Thanks, I sprayed the pots and fixed both rails which had 2 xistors
failed and the zeners and the led were gone too even thought the fuse
was intact. It powers and works now but the feedback control doesn't
seem to do much of anything. Also, there is a time delay before the
phase effect comes in. You plink the string on yer pawnshop guitar and
there's a dry signal for the first third of a sec then the swoosh
sound mixes in. It's the same approx 300ms whatever you set the rate
or depth to be. Is this correct? I've never heard a good unit so I
don't know exactly what it's supposed to sound like, it's pretty cool
though.
Thanks for the advice about the op amps. I have some JC5884 (?)
whatever the originals were, I have 6 here from a cheapo ratshack eq
unit.
Post by JackSpray some contact cleaner into thew pots and controls - that will help
take care of intermittents that way.
How do I know such - used to work for the company when they were in
Rosemont, NJ doing final test and checkout along with repair of customer
returned units. My test equipment (besides DVM and scope)? A Strat and
Twin Reverb.
Excellent choice of weapons, Jack.
Can you remember anything about the calibration procedure? I see there
are two pots in the control section, TP1 and 2 but no voltages.
Also, a separate question on the Mutron III unit. Is the opto unit
Hamamatsu P873-13? A 6pin roach with 4 legs on one end and two on the
other? The part I have has no dot, which is designated in the
schematics I've seen so I don't know which way that would go. Thank
you for your response, s.
** Shelby prepared VibroChamp - UniVox Badazz 6 string electric.**