XSP-1 and my Buzz

[novisnick]

Jul 13, 2015 11:37:57 GMT -5 Gary Cook said:

There's a number of possibilities;

One possibility is that there is a loop from the power amps back to the processor via the pre amp. Keith's suggestion of trying only one channel of a pair of connectors without an earth is one I would try. Got any old RCA to RCA pair interconnects? If so remove the earth/shield from one channel and use the cable as an interconnect between the processor and the pre amp. Read Keith's explanation as to why it's important to be prepared for a loud noise.

I wouldn't suggest doing it between the pre amp and the power amps, that's risky.

With any luck that might just eliminate your buzz.

Cheers
Gary

What time will you be checking back in to this forum? It's now 11:42 AM Monday here and I won't be home until about 2 or 3 PM.
I haven't tried using and RCA to the amps with this pre amp. 

So your suggesting that I connect one amp with RCA and the other XLR? Or both RCA, or just one with and RCA?

[KeithL]

I wanted to clarify a few things - and I'll add a few things that MIGHT help cure your problem.....

First off, hum vs buzz.In general, a ground loop is always going to involve the local line frequency (so 60 Hz in the US and many other places; 50 Hz in some places). If so, then it will sound like a pure low frequency hum if the noise is a relatively clean sine wave, of it will sound like a buzz if the sine wave is distorted. (The main hum frequency will always be there, but it may be covered up by the sharper high frequencies since they are more audible.) Exactly what you get will depend on your circuitry, but both tend to be rather distinctive

Now, there are all sorts of other types of noise which can creep in through the ground - common causes include microwave ovens, computers, cell phones, cordless phones, and WiFi signals. These typically tend to shift around in frequency, and often vary - from minute to minute - depending on the cause. (If it's a cordless phone, the sound will change when you dial a call; if it's a computer, you can sometimes actually "hear it" when you move the mouse or open and close a window on the screen.

There are actually two types of issues you can have with ground noise - and both generally get listed under "ground loops". In an actual ground loop, you actually have two ground connections making up an electrical loop. For example, if you have two interconnects connecting two components, you essentially have two points, connected by two wires. You can see how, in that situation, if you follow the electrical connection of those two grounds, you can trace a complete circle. That circle can act as a transformer winding, and receive noise from magnetic fields that surround it. That is the type of situation where "breaking" one of the grounds will help - once you disconnect ONE of the grounds - at either end - you no longer have a complete circle.

The other, more general, thing that can happen is that you have noise "on the ground". What happens is simply that there's no such thing as a "real solid ground".... it's all sort of relative. Even if you connect the chassis of your amplifier to the ground terminal on the transformer out on your pole using a big fat copper bar, there will still be SOME resistance in that connection. And, if AC current flows through that connection, then that resistance will cause SOME voltage drop. At that point, your "ground" isn't at zero volts, it actually has some small amount of signal on it (the voltage caused by that voltage drop is a signal at the line frequency). The idea behind a "star ground" is that each device has its own wire that goes all the way back to ground. When you do this, even though the grounds of each device may not be perfect, at least you won't have the ground of one device "riding" on the noise that may be there on the ground of some other device... each will instead be independent. Star ground is what we call a topology - a way to arrange things. You can have a star ground inside your amplifier, or your entire house could be wired with a star ground, or both.

The basic overall problem is that we generally "assume" that grounds are really ground (0 volts). So, if the input of my amplifier carries a small signal, and that amplifier amplifies the difference between that signal and ground, but the ground we're using actually has some AC noise on it, the amplifier will then really be amplifying the difference between the input signal AND THE HUM SIGNAL THAT IS ON THE GROUND. In general what we're trying to do when we fight this is to make things so that the grounds on two pieces of equipment are THE SAME - and hoping that their internal circuitry is tolerant of that situation. (So, once we fix things so their grounds are the same, they will ignore any slight hum signal that may be there equally on both.)

So, based on that, here are some tips that MAY help....

1) ALWAYS check the grounds on your cable box and on the TV cable coming into your house. The shield on the coax coming into your house is attached to the ground at the pole, or at the nearest cable distribution amplifier. Odds are there is noise between that ground and your house ground. That's why the cable is supposed to be connected very securely to your house ground at your end, and also to a "true earth ground" for safety reasons. These connections often get loose or corroded, or get disconnected when someone works on the lines (or the guy who installed your alarm system loosened the screw to add his wire to it and forgot to tighten it). To see if this is what's happening, disconnect your cable box from your stereo - if the problem goes away, then you know where to look. (Or call the cable company and tell them you think they've got a "ground problem".) You can also get small devices that isolate the cable input ground (but you have to be careful; some of them may interfere with what channels you get).

2) You really have little control over the way each individual piece of equipment is grounded internally, but you can experiment with the external connections. You can try connecting the chassis grounds of various components together. (Just strip a length of wire and put the bare end under a screw on each chassis to connect them together, or run a wire from each to the ground screw on your outlet plate. There is no wrong or right, just try various combinations and see if any of them help.) Another simple step is to try connecting various equipment to the same power strip, or to different power strips. Again, there is really no wrong or right; just try various combinations. If any of your equipment has un-keyed two prong plugs, you can also try turning the plug around. (Using those little "cheater plugs" that disconnect the ground prong can also help - but it can be dangerous and absolutely violates the safety protection on many pieces of equipment.)

3) Depending on the cause, replacing unbalanced interconnects with balanced ones MAY eliminate the problem.

4) Sometimes, if the hum is being picked up through the air, moving or rotating one or more pieces of equipment will help. (This is the biggest cause of hum on turntables, and moving a turntable a few feet, or rotating it 90 degrees, can have a major impact on hum. And you definitely don't want your sensitive phono preamp sitting on top of your power amp, just a few inches from its huge power transformer.)

5) Avoid running interconnects next to power cables. If you must, then try to avoid running them parallel to each other. If they must cross, then try to do so at right angles. If you've got a rack, at least try to run the interconnects down one corner and the power cables up a different corner.

6) A CMX-2  will filter out high frequency line noise; it will also eliminate or reduce some instances of transformer hum (which can be caused by a DC offset in the line), but nothing can "filter out line frequency" - because, if you filtered out line frequency, you wouldn't have any power left... the hum IS the power... getting into places in the signal chain where it shouldn't be. (Fighting hum is a little bit like trying to keep the floors perfectly dry at Hoover Dam.) The way a full-up isolation transformer works is that it DISCONNECTS the ground on one piece of equipment altogether. (As long as the equipment's OK with that, if the grounds are entirely dissociated from each other, then any noise that exists relatively BETWEEN them simply no longer matters.) However, while you can get an isolation transformer big enough to run a preamp for a few hundred dollars or less, one big enough to run a power amp WILL be big, heavy, and expensive.

The biggest thing to remember is that the process of eliminating hum is often iterative. (No single step removes all the hum. The goal is to try different solutions, keep the ones that reduce the hum, put back the ones that make it worse, and try to find the best combination that gives you the least hum. Hopefully you eventually reach a point where you can't hear the hum any more.)
 

[novisnick]

Thanks KeithL, I've tried most of what you suggest.

My thoughts are this.

There is no cable TV.
I tend to think that the AVR is grounded somehow internally because there is no ground plug to power the unit, only a two pronged plug,

Now, the XSP-1 has a triple plug, two leads and a ground, this I'm assuming means it's grounded outside of the unit?

Both pieces are grounded differently and thus the buzz,,,,,,,,is my thinking correct?
XSP-1 to amps and any input gets me no buzz,
Yamaha 3020 to amps with any input but the XSP-1 , no buzz

I am reading with great interest of your thoughts.

Thank you

[harsh]

Hey novisnick,
As your avr is two plugs only, try to invert it. (If you didn't try already)
It could be a phase problem.

[cawgijoe]

I had success with one of Keith's methods of connecting a wire from the chassis of my Pioneer Elite receiver to my surge protector. Got rid of the low level hum.
However, I swapped that out with an XMC-1 and the hum returned even with the same connection.

It's only noticeable when there is silence and I have not attempted to try running the wire between the XMC-1 and the XPA-5 yet or to the outlet ground screw.

[novisnick]

Jul 13, 2015 13:11:39 GMT -5 harsh said:

Hey novisnick,
As your avr is two plugs only, try to invert it. (If you didn't try already)
It could be a phase problem.

How would I go about inverting it?

thanks

[mgbpuff]

I would try using a cheater plug on the XPS-1. If the noise is eliminated and you want to be totally safe, install a ground protective circuit device either at the specific outlet the equipment is plugged into or replace the circuit breaker back in the panel with a ground protective type.

[harsh]

Jul 13, 2015 14:01:35 GMT -5 novisnick said:

Jul 13, 2015 13:11:39 GMT -5 harsh said:

Hey novisnick,
As your avr is two plugs only, try to invert it. (If you didn't try already)
It could be a phase problem.

How would I go about inverting it?

thanks

Oups, I didn't know US plugs are not invertible...
It's a nema-1 type?

Sorry, european plugs here.

[novisnick]

OK my friends, I've been to Radio shtuff and have purchased this Ground-Loop Isolator to give it a shot, 30 day grace period to return, but I should now soon,,,,,,,,,with a little help from y'all!

Qyestion, how should I hook it up?

the directions are shoddy to say the lease?!?!

[KeithL]

There is no particular issue with connecting different devices together which are grounded in different ways internally; and no particular reason to think that devices that are internally grounded the same way will work especially well together.

Really, your best bet is to try various combinations of grounding the pieces of equipment to each other, and to a real earth ground (ground screw on the outlet box). Remember to try combinations of both the actual chassis (a screw) and the shields of the RCA connectors (since the connector shields may or may not be connected directly to the chassis ground). Also remember to try different ways of connecting the wires (for purposes of grounding, connecting the XSP-1 to the Yamaha, then the Yamaha to ground is NOT the same as running a separate wire from each to the outlet plate screw).

Another possibility (although I can't officially recommend it), would be to try lifting the ground on the XSP-1 (using one of those three-prong to two-prong adapters).

Jul 13, 2015 12:19:43 GMT -5 novisnick said:

Thanks KeithL, I've tried most of what you suggest.

My thoughts are this.

There is no cable TV.
I tend to think that the AVR is grounded somehow internally because there is no ground plug to power the unit, only a two pronged plug,

Now, the XSP-1 has a triple plug, two leads and a ground, this I'm assuming means it's grounded outside of the unit?

Both pieces are grounded differently and thus the buzz,,,,,,,,is my thinking correct?
XSP-1 to amps and any input gets me no buzz,
Yamaha 3020 to amps with any input but the XSP-1 , no buzz

I am reading with great interest of your thoughts.

Thank you

[novisnick]

KeithL said

"I wanted to clarify a few things - and I'll add a few things that MIGHT help cure your problem".

1) there is no cable box at all

2) have tried this before without any change in buzz

3) I am using balanced cable with no different outcome then unbalanced.

4) I don't believe the buzz is being caused by the amps but by the Pre amp and AVR interaction.

5) interconnects and power lines are as far apart as possible.

6) No matter how I configure the power lines from one or the other or both using the a CMX-2 , there is no difference in the buzz.

A reduction of the buzz would be nice, can I live with it?,,,,,,,If I have too,
The buzz does not get louder as volume is increased, so it seems to disappear at volume.
Playing directly from the XSP-1 , or the Yamaha 3020 produces no buzz,,,,,,,run the interconnects from one to the other and engage HT Bypass,,,,,,BING, WE HAVE BUZZ.

More help please! 8)

[novisnick]

Jul 13, 2015 15:38:24 GMT -5 KeithL said:

There is no particular issue with connecting different devices together which are grounded in different ways internally; and no particular reason to think that devices that are internally grounded the same way will work especially well together.

Really, your best bet is to try various combinations of grounding the pieces of equipment to each other, and to a real earth ground (ground screw on the outlet box). Remember to try combinations of both the actual chassis (a screw) and the shields of the RCA connectors (since the connector shields may or may not be connected directly to the chassis ground). Also remember to try different ways of connecting the wires (for purposes of grounding, connecting the XSP-1 to the Yamaha, then the Yamaha to ground is NOT the same as running a separate wire from each to the outlet plate screw).

Another possibility (although I can't officially recommend it), would be to try lifting the ground on the XSP-1 (using one of those three-prong to two-prong adapters).

Jul 13, 2015 12:19:43 GMT -5 novisnick said:

Thanks KeithL, I've tried most of what you suggest.

My thoughts are this.

There is no cable TV.
I tend to think that the AVR is grounded somehow internally because there is no ground plug to power the unit, only a two pronged plug,

Now, the XSP-1 has a triple plug, two leads and a ground, this I'm assuming means it's grounded outside of the unit?

Both pieces are grounded differently and thus the buzz,,,,,,,,is my thinking correct?
XSP-1 to amps and any input gets me no buzz,
Yamaha 3020 to amps with any input but the XSP-1 , no buzz

I am reading with great interest of your thoughts.

Thank you

I really do appreciate your efforts here my friend!

the recepticals are of plastic construction and will be no help.  

[KeithL]

I don't know which one you bought.... however, if it goes in the signal path at line level, then it probably has a transformer in it, which means that it WILL affect the sound quality.

Jul 13, 2015 15:25:13 GMT -5 novisnick said:

OK my friends, I've been to Radio shtuff and have purchased this Ground-Loop Isolator to give it a shot, 30 day grace period to return, but I should now soon,,,,,,,,,with a little help from y'all!

Qyestion, how should I hook it up?

the directions are shoddy to say the lease?!?!

[novisnick]

Inadvertent post! 8)

I've also tried the cheater plug.

How about the ground loop isolator?

[novisnick]

   

Sorry, I thought I had posted this.

[novisnick]

Should it go from the pre out L/R of the Yamaha to the HT in RCA OF THE XSP-1?

[novisnick]

Jul 13, 2015 15:51:43 GMT -5 novisnick said:

Should it go from the pre out L/R of the Yamaha to the HT in RCA OF THE XSP-1?

                                                                                

[monkumonku]

Just how loud is this buzz, anyway? I think you said it is not dependent on the volume control, so how far back from the speakers can you hear it?

[yeeeha17]

wasn't this your old setup? And you didn't have a buzz than

[yeeeha17]

nevermind different amps and speakers are in play