[Brandon Briesath]

Had to re register. Been a long time since I’ve been on here.

Trying to eliminate a very annoying 120 hz buzzing sound coming through my setup. I’ve tried tons of things, new surge protectors, different outlets, hum x, etc. it’s a buzz that come on every 6-8 seconds, buzzes for a few then goes off, never stopping.

My setup is very complex.
Yamaha cx5000 pre
Parasound amp a21
Parasound pre p7
Behringer fbd
Dual subs
Custom built pc with 200 watt external power supply
Schiit dac
Directv box
Sony ps3
Outlaw 7 ch amp for surrounds and zone speakers

I’ve tried unplugging cables many times and can’t seem to locate the root of the problem.

Any suggestions on where to begin?
Thanks.

 

[Wayne A. Pflughaupt]

Try unplugging the DirecTV box from the system.

Regards,
Wayne

 

[Brandon Briesath]

Try unplugging the DirecTV box from the system.

Regards,
Wayne

This was one of the first things I tried and nothing changed. Im guessing its a ground loop issue but honestly don't know how to remedy it.

 

[Wayne A. Pflughaupt]

The antenna lead? Because that’s where the problem would be, not the audio connections.

Ground loops are caused by different paths to ground. Often CATV or satellite do not have their ground lead go all the way to the house electrical ground stake, so that’s why I recommended disconnecting it.

Next, make sure all the system components are plugged into the same electrical circuit.

If that doesn’t help, disconnect and unplug everything in the system except the pre-amp, amp and speakers. Then add components back in one at a time.

Regards,
Wayne

 

[Brandon Briesath]

The antenna lead? Because that’s where the problem would be, not the audio connections.

Ground loops are caused by different paths to ground. Often CATV or satellite do not have their ground lead go all the way to the house electrical ground stake, so that’s why I recommended disconnecting it.

Next, make sure all the system components are plugged into the same electrical circuit.

If that doesn’t help, disconnect and unplug everything in the system except the pre-amp, amp and speakers. Then add components back in one at a time.

Regards,
Wayne

So unplug the antenna/satellite feed coming into the directv box? I will try this again and see. Im pretty sure I've ruled this out already but will double check.

I recently plugged all of my components into the same outlet, again trying to rule things out. I will do more trouble shooting this afternoon. I have a remodeling project starting this spring. Can something be done at this time via electrical work to remedy this issue if I cannot find the culprit?
Thanks for your help!

 

[Wayne A. Pflughaupt]

I have a remodeling project starting this spring. Can something be done at this time via electrical work to remedy this issue if I cannot find the culprit?

Have one or two dedicated circuits put in. If more than one, make sure they are on the same phase.

Regards,
Wayne

 

[Brandon Briesath]

Have one or two dedicated circuits put in. If more than one, make sure they are on the same phase.

Regards,
Wayne

Gotcha! I had thought about doing this already. So one dedicated circuit/breaker in the panel just for my gear in that setup correct? Is there any chance that the grounding on the panel is the culprit in which a dedicated circuit wont help?

 

[Wayne A. Pflughaupt]

I don’t see how that would be possible. The electrical grounding system is pretty simple, if it’s done correctly. So I guess the key phrase there is “done correctly...”

Regards,
Wayne

 

[Brandon Briesath]

I don’t see how that would be possible. The electrical grounding system is pretty simple, if it’s done correctly. So I guess the key phrase there is “done correctly...”

Regards,
Wayne

The house was built only 10 years ago and I don’t invision the grounding to be done incorrectly. I suppose it’s a possibility but unlikely.

 

[Brandon Briesath]

Well I unplugged the satellite feed (rg6 cable) coming into the directv box and unplugged it’s power source and nothing changed. I also confirmed the outlet that all my equipment is plugged into is a dedicated one with nothing else on it. Still that hum/buzz.

I’ll try leaving just the amp, preamp, speakers connected and process of elimination from there.

 

[Brandon Briesath]

One discovery which I hope is relevant. So my Parasound P7 has HT bypass which I of course use in my setup. When it’s in bypass, meaning I’m using the Yamaha CX-A5000 for volume, sources, etc, the buzz is audible like I’ve described. As soon as I switch the Parasound P7 to any source coming into it other than HT bypass, the buzz disappears completely. So for example, if I switch the P7 to my music input coming from my Schiit DAC, the buzz is gone!

Does this help narrow things down?

 

[RTS100x5]

Hi Brandon - its a process of elimination really

Is is in all speakers or just subs ??
1. disconnect all sources - is it still humming
2 . disconnect subs signal cable from subs 1 at a time.. is it still buzzing through speakers


If it's in all speakers probably an issue with your pre amp - unless its related to one particular source...

 

[Brandon Briesath]

Hi Brandon - its a process of elimination really

Is is in all speakers or just subs ??
1. disconnect all sources - is it still humming
2 . disconnect subs signal cable from subs 1 at a time.. is it still buzzing through speakers


If it's in all speakers probably an issue with your pre amp - unless its related to one particular source...

I agree. Rather than disconnecting all of the sources, then adding them back one by one, I chose another path simply to avoid forgetting how everything was connected

I disconnected one source at a time, listening for the hum, then reconnecting it and moving on to the next source. Will this process work too? If so, then I basically tried what you suggested already. I removed every source at some point, even the subs, nothing changed.

 

[RTS100x5]

Kinda of confusing why you are using 2 pre amps ?

 

[Brandon Briesath]

Kinda of confusing why you are using 2 pre amps ?

The Yamaha is for Audio and Video. Such as Movies (Blu ray, Directv, etc). The parasound P7 is for audio only. The reason the P7 has HT bypass is so one can incorporate a Stereo (music only) preamp into their setup while utilizing their receiver/processor (in my case the Yamaha CXA5000) and existing amps. Its complicated yes, but very typical.

 

[Brandon Briesath]

Here are some wiring diagrams.....

 

[RTS100x5]

Interesting, though I fail to see the need for the P7 ...Usually in that scenario - Im just sending the yamaha pre outs directly to the 2ch amp...in any case if your switching the HT bypass on/off and the hum goes away then I suggest therein lies the problem , but you probably know that...

 

[Brandon Briesath]

Interesting, though I fail to see the need for the P7 ...Usually in that scenario - Im just sending the yamaha pre outs directly to the 2ch amp...in any case if your switching the HT bypass on/off and the hum goes away then I suggest therein lies the problem , but you probably know that...

The P7 is NOT necessary but sure sounds better than running a quality 2ch source through my Yamaha. A dedicated 2ch preamp makes a big difference in most systems, but again YMMV

I have reached out to parasound to get their take on this. Its also possible the buzz is coming from the Yamaha into the P7. Stay tuned.

 

[Brandon Briesath]

So I think I fixed it! The Parasound A21 amp has two options for Input, balanced and unbalanced connections. I removed my balanced XLR cables from it and the p7, and replaced the pair with good old RCA cables, flipped the switch on back of the A21 and guess what, the buzz is nearly inaudible!!

I have no clue why this fixed it but so far so good

 

[Wayne A. Pflughaupt]

Wow, that’s startling. If anything, I’d have expected going from unbalanced to balanced would have made a difference.

Regards,
Wayne