Method to cut Hermod CPU noise in cv + audio path


Hi Forum and Squarp Team,
I’ve been trying a few options to reduce a noticeable high freq processor noise coming from the Hermod CPU that is insidious and hard to cut out of the final mix… i’ve tried switching power supplies (Frap Silta, then 4ms Row Power, the Malekko power) also moving to different skiffs that have no submixers passing audio to the main mix…but so far it’s not possible to cut out the processor whine. It seems to transfer even through any cv signals as well (transferring into the filter or VCO or VCA that’s receiving the pitch cv or modulation cv.
I’m looking for any suggestions how best to cut or reduce this particular frequency without totally cutting it from the final mix (with loss of much other high frequency content)… any tips or tricks how to isolate or remove would be much appreciated.


I was having a hideous high pitched sound when connecting two different cases together using Hermod.
It took me a minute to track down the problem, and it turned out to be the stock power supply which ships with the Intellijel 4U cases.

MeanWell GSM60A15-P1J
15v - 4A - 60W

When I disconnect from the main case, the noise was gone.

I posted a series to Instagram about this:
https:// www. instagram. com/p/BiaXjcRAJsc/

I corrected this swapping the GSM60A with a second PSU

MeanWell GSM90A15-P1M
15V - 6A - 90W

I happened to have a second for the main case around because of the grounding issues with a René which needed a different grounding scheme. When I use the GSM90 with both the main case and the 4U case the noise is completely gone (as shown in the instagram series.)

I’m relieved that for me it didn’t turn out to be the Hermod at all.


Hi Sunshine,
This is invaluable intel!
Much obliged for sharing.
I’ll track down a different brick this week and give it a shot.
Loving the Hermod more and more so very happy to hear of potential easy resolve.


I have exactly the same issues here.
@Tanzforsyth : Have you solved your noises and cracks in the cv + audio path ?
@Sunshine : Sorry but your instagram link doesn’t work. I’ve looked at the power supplies references, they have 2 differences, 60W versus 90W, and also the jack for plugging the power in the system. The 90W have more than 2 electrical points. It is the case, please ?
Mine is ever 90W, exactly same specs.
I have tried so many different configurations.
With SynthRotek deluxe power / 4ms Row Power, same problems.
I hear a sort of CPU noise in all my system outputs.
And the cv path is not clean at all ( 1v/oct swag a lot, causes a sort of chorus effect in mu 1v/oct MI Clouds input ) .
Many thanks for your help,
Hope I’ll can benefit of all the Hermod’s power :wink:


Got the GSM 90 brick and did the trick thanks again


The link is sanitized by this board. Sorry about that.
Take a look in the address bar and remove the 20% business and it’ll take you there.


I’m having a similar issue, hearing a faint CPU whine from the Hermod. While it’s minimal, it can still come forward in the mix after EQ and compression.

Knowing embarrassingly little about power, would I be able to use the MeanWell GSM90A15-P1M on something like a Make Noise case?


Answered my own question above (yes the Meanwell PSU works), but unfortunately I’m still hearing the whine. For what it’s worth I was also experiencing the whine with a Doepfer PSU3.

Wondering if this is something every experiences (and deals with) or if my unit is particularly loud for some reason or another. Do the rest of y’all hear it when the system is cranked?