I’ve been doing a bit of digging on this subject recently and it’s a proper can of worms. It looks like a few of us are experiencing ground noise from our power supplies, and there are multiple things we all need to do to actually fix it.
It isn’t the 301’s fault I don’t think, it’s just high load so creates this problem easier than other modules, that and because it’s DSP. I’ve had the same thing with the Make Noise Erbe Verb funnily enough. In my system, it manifests in a high pitched whining sound that’s also a bit noisy. No hum though. Is your power supply a switching type by any chance? They are the biggest culprit from what I gather. Apparently, linear supplies can create this problem too though…
Check out this thread on Muff, be warned though - it turns into a shitstorm and I’m still trying to figure out who’s right and who’s, well, not…
Also, @NeilParfittmay be able to offer some insight as his system is utterly ridonculous, and has all the necessary trimmings so to speak which cure/drastically reduce this problem. It certainly doesn’t look cheap to fix though… Blimey.
The “Brief measurement” and the “recording” sound like different pitches. The latter sounds like switching power supply noise.
Tons of gear create an audible noise as part of their operation:
OLEDS (as Brian Mentioned)
anything with inverters/EL backlights (like many rackmount synths
various video cards (I can hear my MacBook air on occasion)
Some CPUs … many found in Eurorack … and even big computers such as the Apple G5 (chirped!)
Linear Power transformers
I have questions:
What power / busboard combination are you using?
What was connected to the module during recording?
What was your pre-amp gain in admin area set to?
For comparison, below is the self-noise of my ER301 recording from IN1 at euro-gain. I have 4000HP of modules on the SAME supply and power distribution:
As you can hear, contamination is irrelevant in real-world use. Below is the same thing boosted 40dB! You can hear that the noise is uniform. There’s no obvious whines or things jumping out. Switching is notorious for that problem BTW, especially the cheap ones.
So there must be an outside factor related to my three questions.
@pMod Yes, I’ve been to hell and back finding the optimal power/noise solution for such a large scale system. And it’s only this year, that I can say without any exaggeration that my Eurorack gear is on par with my pro outboard gear and can treat it as such when processing.
Before - Noise reduction, Notch EQs, you name it … was the norm.
My system now is powered by Acopian Linear supplies, centralized bus rails for 12/-12/C/5, heavy gauge wire, doubled up common and Genus Modu LIBB bus boards. I’ve been through THREE sets of bus boards, and flipping to the LIBBS was night/day amazing and was my last resort at the time.
People arguing against it on Muffs have no clue what they’re talking about so I woldn’t waste your time reading it.
Personally, I’m on Doepfer stuff. I’m a bit gutted with myself for causing a nightmare in the long run. I use PSU3’s and their bus boards too, the wire isn’t the right gauge even. I have quite a bit to do it would seem.
Excuse my ignorance, but what’s ‘doubled up common’? That’s the only bit I’m not with you on.
When I first found out about the Genus LIBB bus boards I was thinking I could possibly just get a couple and run the 301’s off of those, you know one on each bus board kind of thing, as they’re the only module really being affected by this at the moment - I ended up getting rid of the Erbe Verb.
Oddly enough, even though it draws even more power than the 301, I’ve never heard this with the Intellijel Rainmaker. I have no idea why it’s exempt either!
However, reading that thread made me believe that would be a waste of time/money. Would you agree? Is it worth a shot at least to get a bit of a reduction? Or, is it one of those things where it only really goes away after you’re a good little boy and do everything correctly?
Thank you for cutting through some of the muck on this Neil. You’re a gentleman and a scholar!
Yeahman, it’s the brick I was referring to. You either get linear or switching types, from my experience linears have a big heavy coil in them and the switching ones have these black sealed blocks instead and are lighter. Or at least that’s how it works in Doepfer supply land (PSU2’s are linear and the PSU3’s are switching).
The gauge wire is also important apparently, the stuff we get given in a case is half what people on that thread (and what Neil’s system uses) suggest is good for the job. Then there’s the common (what I thought was GND) configuration which I’m still trying to get my head around, to be honest!
Most importantly though is those bus boards, as they have capacitors and resistors on them as to kind of filter/control the power better. They appear to be the only bus boards you can get like that. From what Neil’s saying, he didn’t get his system totally right until those were added. There are also these bus rails for bigger systems too, so you’re not running huge lengths of cable to the bus boards, as that affects things as well (apparently anything over 18’’ in length).
Cheers Neil! I don’t know whether you can answer this becuase you seem to have one massive block for everything, but can I attach more than one supply brick to a set of those bus rails? Or will things get a bit explodey?
Regarding common - do you do that thing suggested with it where the bus boards are interconneced, rather than to the supply brick common? I really didn’t get that bit on the Muff thread it just confused me!
Or is doubling up using two wires instead of just one? And they both go to the same place so to speak? Is this like a headroom kind of thing?
Gradually I’m seeing things clearer, but I still have a way to go I think!
Yeah thought so! Hahaha… I’m obviously no electro engineer but that didn’t sound right at all after putting it out there. Ok well I’ll have to either replace all the power bricks I was going to use or come up with a workaround, probably involving having them as close as possible to the bus boards that they are connected to.
Here’s me thinking I had the design of my next case all sorted in my head! Back to the mental drawing board… I’m a way off anyway as my next one is going to be 6 or 7 rows of 1100mm wide, and I don’t have either the modules to half fill that yet, or blind panels for that matter!
Thanks for your advice on this man, it’s really appreciated.
A note that the entire UOV and Relay power control aren’t required on a small setup.
I implemented this elaborate failsafe to protect my investment (as it’s about 4k HP worth) The system is running a single set of split supplies to create the +/-12V and are extremely powerful so there needed to be an automatic failsafe:
The entire rig will immediately turn off if:
any of the supplies die or lose power from a blown fuse
any of the supplies generate voltage above and below a set threshold
There’s Voltage loss on any of the primary 12V/-12V/5V bus rails in each case