I am wondering if I am pushing this power supply too hard. I have always gotten some unwanted noise that I am trying to diminish. I bought the AC adapter from amazon with an input of 100-240V - 1.8A 50/60Hz and output of 19V-4.74A. Is my problem there? Or somewhere else. Any advice would be much appreciated.

ModularGrid Rack


Simply judging by the specs you should be fine. What kind of noise do you get? Does it appear in every patch or only in certain combinations? For example, do you have a high noise floor already when patching only Rings to the Audio I/O? Try disconnecting all modules from the bus board/flying bus cable and reconnect one by one, starting with the Audio I/O. At which point does the noise appear?

The A-199 can add a lot of noise to the audio path. Try placing the springs somewhere else, make sure both the springs and the cables aren't too close to other electrical circuits. Try replacing the RCA cable with one that's better shielded.

I don't have the A-106-1 but a lot of MS-20 style filters can be rather noisy (by design).
But of course, the AC adapter might well be the culprit.


Plenty of problems here...starting with the placement of that Row30. NEVER put a power device anywhere near an audio module. This is the easiest way for noise to get into your audio path. Also, consider getting a different power brick; inputting 19V into a module whose max is 20V is probably overtaxing the Row30.

EDIT: Got interrupted...also, you might want to add a ferrite to the DC line into the Row30 if it doesn't have one already. Cheap switching supplies such as ones found in OEM bricks often spew garbage down the DC line. In a lot of devices, this isn't an issue...but with a modular synth, you can have so many different analog and digital circuits crammed together in a tiny box that, once some RF or other such crud gets in, it'll interfere with loads of these and numerous noise generation points can emerge.

One other suggestion might be to get rid of the brick altogether. On my AE system, I use a Tektronix LINEAR supply. These aren't subject to generating anywhere near the amount of crud a cheap switching supply typically puts out. The unit I use is a PS282, which is more than capable of powering that 160-space mutha with ZERO need for ferrites, etc etc. And mine was even calibrated by the seller (Valuetronics, up in the Chicago burbs) prior to sale, so it's 100% in factory spec...for only $100-ish. Plus, unlike a lot of linear supplies, this TEK is portable...it's about the size of a lunchbox, and even has a carry handle for convenience! With this thing on the AE, all of the VCOs stand right at attention, there's little to nothing atypical as far as noise goes, and the stability is...well, the ripple scopes out at something ridiculously low, essentially negligible, so that modular runs rock-solid.