FREQUENTLY ASKED QUESTIONS

Jonathan Little here, I‘m going to start cutting and pasting, very informally, questions I’d like to address (in other words, faqs) with answers. This will be my first one below, it’s 04/11/21. Dig around before contacting me if you can. I’ll put in bold the product that is referred to before the question.


MONOTOR
I recently purchased a Monotor, and am very pleased with it except for one thing: there's an intermittent low-level RF noise/chirps. The noise volume stays the same as I adjust the level control, making me wonder if it's a power amp issue. It's fairly apparent on my Sennheiser HD 580s, and even more so on my IEMs. I did read in the manual that the Monotor is susceptible to such noise, and should be placed well away from any Wifi routers. Well, my wifi router is in the other room and I've mounted the Monotor at least a couple of feet away from any potential wireless devices (i.e. my iMac), so wondering if it could be an issue with the device itself. If there are any quick electronics fixes to try, I dabble in tech repair so would be down to try. Thanks!

Here’s the answer.
Your unit I’m pretty sure is not broken, but this explains why these noises are there, and what you can do to hopefully alleviate in your environment. The Monotor is susceptible because of it's high gain and wide bandwidth to phone and wi-fi air born "chirp," very high-frequency stuff, but it rectifies in the circuitry causing those intermittent audible zip zap zorch noises. This is more noticeable on sensitive, low impedance phones especially high sensitivity IEMs. I use as my reference phones the LCD-X Audeze and the HD-600, 650, and 580 Sennheiser, and it will be more evident on the LCD-X because of the higher sensitivity. The level control is pre the high gain amp, so that's why you will still hear it with volume down. I did some experimenting here in the lab, and sure enough, not so much my apple router, but the one that came with my internet provider I have to have that about six feet away from the monotor. The apple one I have to stick the monotor right on top to hear interference, it will also do it with my iPhone sitting on top. I'm not sure if that is what is going on here. The level trim is before the high gain amp (so turning it down won't change anything). In some instances, I have found like in an NYC apartment building with routers all around with strong wi-fi, it's more difficult in placement.

I looked into remedies that included ferrite beads and narrowing the bandwidth, all of which reduced the interference but also in very critical listening reduced performance by enough that I felt leaving the circuitry wide open and moving the offending router was the better option. I talked to other hi-end audio people, and universally they stated wi-fi routers have no place anywhere near hi-end audio gear. I use the monotor in the lab as a sonic microscope on gear to hear stuff way down in the noise floor like dying electrolytic cap noises. This super-sensitive ultra-low noise wide bandwidth circuitry has its place and your other gear with gain like mic pres, although you don't hear it now if you stuck your router on top of it and listened loud with the monotor (not on top of the router) it's there but so far down it doesn't matter.

Another source of weird noises entering the monotor is the third prong AC. Try plugging in a different outlet and avoid some power conditioners, the "MONSTER" brand is especially notorious. If you have an AC third prong cheater plug (see pic below) or an extra IEC AC cord, you could butcher to check if the problem is occurring through that third prong ground, try lifting, and see if it helps. Audio ground and ac ground are attached on the Monotor, which is always a debate in audio circles as to which is better, attached, or not attached. It is attached on the monotor, but I'm considering changing it because of the use in less than pro environments.

Hope that helps,