Hum through AC mains in subwoofer (not ground hum)

[GXAlan]

I agree. The only reason I got invested was because of how quickly he (and some of his supporters) were to say "Well it just happens sometimes, turn the Gain down".

+1

Monolith was great with the HTP-1 and the company still benefited from the community input.

Surprised Power Sound Audio isn’t seeing this as an opportunity to take their subs to the next level. When you fix the noise, you can have more gain on your subs! (And their subs are pretty good).

PSA has slowly raised the prices since their launch, adding new features and it seems like your tweaks are so easy? The hard part was your troubleshooting.

 

[restorer-john]

@Buckeye Amps I think you've gone down the correct path. Isolate the problem, investigate the cause and implement a solution that works for you. If you aren't using the RCA inputs, it makes no sense to have them connected and causing hum issues.

Why they don't have a physical selection of the input type is ridiculous. Unused inputs should always be shorted, even on physical selectors as noise can easily get in otherwise.

As for DSP noise gate settings, it's not hard to design an adjustable analogue auto power on/off that is immune to the issues they clearly cannot solve with "DSP" triggering.

 

[ryanosaur]

but he has made it clear on AVS that the issue is dirty mains power and there is nothing to be seen here. So not going to waste any more time on it.

This, among everything else you wrote about this is exactly why I won’t ever support him and his company. Everything you described is an absolute red flag. Him blaming the power is just the icing on the cake.

 

[ryanosaur]

Oh… and you should bill him for your time troubleshooting his product.

 

[Paffi]

funny - I have the same problem since the same day (no joke, it was friday), as I replaced my wireless connection of the subs to cable connects (rca). There is hum, altough no RCA connected - same as you. But it´s another sub manufacturer (also 2 pin connector for power). I figured out, that when I unplugg some devices, plugged in at another wall socket (but the same main fuse), the hum disappears or gets much lower in noise. In fact in my case it was the wall plug of a minidsp. My solution was to turn the amplifier in the subs as low as possible and the gain in the preamp as high as possible, so it´s not that audible anymore...

 

[Sokel]

funny - I have the same problem since the same day (no joke, it was friday), as I replaced my wireless connection of the subs to cable connects (rca). There is hum, altough no RCA connected - same as you. But it´s another sub manufacturer (also 2 pin connector for power). I figured out, that when I unplugg some devices, plugged in at another wall socket (but the same main fuse), the hum disappears or gets much lower in noise. In fact in my case it was the wall plug of a minidsp. My solution was to turn the amplifier in the subs as low as possible and the gain in the preamp as high as possible, so it´s not that audible anymore...

As @pma always says mixing class I and class II devices is usually the source of most problems.
What's with those 2-prong subs lately?Easier to certify?

 

[Sokel]

Ok,found a silly test I did.
That is a device (audio,doesn't matter what) connected to NOTHING except the ADC that measures it.
And I mean nothing,no power,no lines,none,zero.
That's how it looks like:

I then only grounded it (is still off,no other connection than a wire connecting it to ground) :

(long 6 meter cables and low input impedance does the hump low)

Nice,ha?

(Edit:I know I have a nice antenna here,but it's way different than with open vs shorted cable for example)

 

[GXAlan]

@Buckeye Amps
I have to say thank you for this thread, even though I originally was questioning you. I just picked up a S1813M myself, and by the time you unbox it, you really don't want to have to ship it back

I moved it into the tight corner and, well, I got the hum too. I opened up the 16 screws, disconnected the RCA internally. Instead of shorting the second XLR, I ended up running a cable to an unused output on my processor. It's a waste if you don't have the extra space, and a problem if you were running quad subs. I wonder if a simple Y-splitter would work without shorting the input?