Whats the general consensus regarding noise output from Moog Modules?
are they quiet or do they, like mine particularly the mixers, emit a low hum. Ive noticed when recording and the mixers are turned high the hum is pretty bad. All my cables are balanced etc its def the Moog giving the hum.
Moog modulars tend to establish ground through the star washers on the jacks then to chassis ground on the module panel. They didn’t wire the sleeve terminal on the jack.
If the star washers are rusted, they won’t have good continuity to ground.
Other than that you’re looking at a ground loop problem.
With all due respect to MC, many Moog modules DID wire the grounds on their jacks.
This rumor actually led Synthesizers.com to leave out lock washers, from what I understand.
A big mistake in my opinion because they may come loose in years to come and the barrels stick out farther than stock Moogs.
All old manufacturers used lock washers regardless of whether they wired their grounds- Arp, Oberheim, Buchla, Polyfusion, EML… on and on.
There were exceptions of course- Some Moog modules, the EML 400, Arp Sequencer and others.
But the rumor that ALL Moog modules used just the washers for their grounds is just that, a rumor.
Here, take a look at an old 901 VCO:
http://www.synthfool.com/inside901.jpg
Has your power supply been recapped?
That’s the first I’d guess.
Check it by itself using headphones or portable (battery powered) amp.
Thanks MC and Kevin…all grounds checked OK
Power supply is supressed with huge capacitors,
I dont suspect this although not ruling it out.
What I suspect is inherent noise from the transistor circuit
of the the CP3 panels and 4 x 4 mixer, this is old stuff design wise
but I want to keep with the original stuff. The other modules are mainly hum free.
Kevin..great picture of 901 gibblets!!
The two CP3’s I have here are hum free. Now if I krank up a monitor, there is a small amount of hiss. They are not silent.
Could try a variable bench supply with +12 and -6 to see if it is from your PS. I’m guessing these are DIY CP3’s? I could post a scan of a stock board, very small circuit, but a big part of the sound.
LOL, that would be my photo work of my 901. I keep forgetting to put a watermark in the corner. 
Here is the page they were lifted from:
Moog 1P photos
Just click on some the pics to get the larger version.
Ditto on the grounding the jacks. That one was built in 1969, while most jacks are grounded, there are a few that rely on the serrated lock washer for ground, like the multis on the CP7 panel.
CZ, is that a Sequential Programmer on the left at the bottom of your page?
I haven’t seen one of those in 30 years! 
It’s DIY!
I needed a counter to advance the 960 rows at different musical intervals, like 5 or 8, so I made that one. Just used a blank dotcom panel and a 4017 for the 8 up counter (left column), and linked a 4024 for divide by to /64 (right column).
Below is an AND gate so between the two I can get odd counts like 11. I thought the old style incandescent indicators looked great.
They have a warm glow to them.
Just 
…
Impressive… 
CZ, my apologies for not obtaining permission on the pic.
I just did a quick search of my hard drive and located that one.
It won’t be included as part of the synthfool site proper where I will be placing watermarks on all the pics. (not schematics though.)
I simply don’t have a Moog modular here at the moment and it was the quickest way to make the point that not all Moogs used only washers for grounds. So my apologies. There was no malice involved, just a desire for education where it might be appreciated.
I personally believe in drawing a line between someone’s artistic work and general tech knowledge and failed with this one example.
Hey, no problem Kevin!
I think I still owe you a few, as I used your method for cleaning my ARP Odyssey buss bar. That still works great, duophonic, and it’s been a few years now.
You and the forum can certainly use any pics I upload here.
I still think it’s cool that I can upload these Moog images to be viewed around the globe. Wasn’t that many years ago, magazines were the only way to get Moog porn!
Every once in a while, I’ll take a break from playing, and snap a photo.
Each pic seems to amaze me more than the last CZ. Thanks very much for sharing! You’ve got a lot of great gear and it’s even better that all of it is being used and enjoyed.