Hi all! I am new in the forum!
I am trying to build an EH Microsynth (I know don't tell me I am crazy ), I have just a question to people that have this beast. I'd like to know how each pin of sweep rate and attack delay potentiometers is wired. If you have some pictures of the inside of the unit you would help me so much
Many thanks in advance !!
I can see why you're asking, the schematic has the third pin floating out in space. I'd suggest you leave them unconnected unless they cause you a problem - in which case I'd short the "floating" pin to the wiper.
I can see why you're asking, the schematic has the third pin floating out in space. I'd suggest you leave them unconnected unless they cause you a problem - in which case I'd short the "floating" pin to the wiper.
In the second link (page 2) pin3 of attack delay seems should be connected to negative supply and pin3 of sweep rate to ground. So I was asking if anyone could check this on a real unit. Thanks for all your replies
The design has gone through a few revisions, what you've posted seems to be the original schems from 1972 - prior to even the first revision which seems to have come in 1978 (if the link Jazz Ad posted contains accurate information) and prior to much more recent revisions.
I think you'll find that some units are wired one way and others another way. Checking the hardware is only likely to demonstrate that there's more than one "right" way.
I think the pdf version is just a digital redraw of the scanned schematics that I have posted because the revision dates are the same 12/12/78.
The only difference is the pinout of the two potentiometers. Anyway, some people have found some other mismatches between the real unit and both of the schematics. So I thought the best way to check the right connections of pots was by directly seeing the inside of the unit.
Last edited by DVB_master : 08-19-2007 at 06:34 PM.
Well, if it is a redraw I'd be tempted to go with the original... The engineer in me says it's bad form to leave one end of a pot unconnected. The trouble with checking it on a real unit is that it requires a fair degree of disassembly before you get to the board with the pots on it.
you're right man, I think I'll follow the original schematic and if there are problems I'll try in the other way.
Anyway If sombody has the microsynth already disassembled , you're welcome to check this or take some photos
Thanks!
you're right man, I think I'll follow the original schematic and if there are problems I'll try in the other way.
Anyway If sombody has the microsynth already disassembled , you're welcome to check this or take some photos
Thanks!
The hand drawn and pdf versions ARE two different versions of the MS, not just redraws. Go with one or the other. Those connectionless lugs are correct. You should search for micro synthesizer at www.diystompboxes.com. There's lots of discussion s about the versions, errors, corrections, mods, DIY versions, etc.
__________________
"What's more romantic than dying in the moonlight?"
P-Bass Club #466, Hollowbody Bass Club #29, Electro-Harmonix Club #1, Texas Bassists Club #61.
), I have just a question to people that have this beast. I'd like to know how each pin of sweep rate and attack delay potentiometers is wired. If you have some pictures of the inside of the unit you would help me so much 
So I thought the best way to check the right connections of pots was by directly seeing the inside of the unit.
