Hum issues hooking up Pro Audio (Crown) amp to Home Audio Receiver (Yamaha)

E

ENDEE666

Audiophyte
Hello everyone. Hoping someone can help me solve an issue I am having. I am expanding my sound system in my den at home. Mostly with stuff I already own, while adding a few new items. I have done a lot of troubleshooting already, and wanted some guidance before I started throwing more money and parts at the problem. This forum has always been a big help, even just from searching, and resulted in a few of the items I am now integrating into my home system. I know a lot of this stuff is Old School, but I really prefer the older stuff in most cases.

So I am hooking up a Crown XLS1000 amp to power 2 separate 10" vented subs I am building. I know, Crown is mostly Pro Audio oriented, but it had RCA inputs. However, I overlooked the input sensitivity, which is adjustable on all other Crown lines with RCA inputs. But not this one, of course. Oversight that I regretted. And so hum or no hum, the output was whisper quiet. So I bought a Samson S-Convert (basically the same as Rolls Promatch & ART Cleanbox) so it would not only boost the signal, but could also convert from RCA to XLR. So in the future I could upgrade to any Pro Audio amp.

In addition, my Yamaha RX-V2095 (from ~2001, LOVE IT!) is 5.1, and also has a preamp out/in loop for an external EQ or processor, or even amps for all channels. So I wanted to utilize the out/in loop to hook up a Behringer DSP8024 EQ I have had for years, from back when I DJ'ed weddings & events. This does not have RCA in/out, only the XLR. But I already had some XLR>RCA cables, plus I now have the Samson that boosts & converts from RCA to XLR.

So that's the goals. Hook up the EQ with the Samson S-Convert on the EQ loop, and hook up the Crown XLS1000 to power the two subs I am building. Now.. Here is the situation:

When ever I hook up either the Crown or the Behringer to my Yamaha, I get a very bad hum/buzz from the speakers. I have done the following troubleshooting:

~Tried using the sub out RCA as well as the EQ out/in RCAs, to either the Crown or Behringer. All combinations get the hum/buzz from the speakers connected to the Yamaha.
~I tried with & without the Samson S-Convert in line, hum no matter what.
~I tried plugging the power for the 2 Pro items to different power strips, as well as different outlets. No changes.
~To reduce variables, I even went straight from sub out on Yamaha to the Crown RCA in, without even speakers connected to the Crown, no EQ or Samson S-Convert. and still had hum on the speakers connected to the Yamaha.
~With the RCAs hooked up on the Yamaha side, but to nothing else on the other end, NO HUM at all!
~I then took a spare receiver from a different room, and hooked that up with RCA from the Yamaha sub out to an audio input on the spare receiver, and there was no hum.

So the hum only exists when either of the Pro Audio items are connected, in any way. I know they mostly desire Balanced XLR. But the Crown has RCA inputs, so I don't see why that's an issue. If I got the hum when using the XLR>RCA adapter cables, then I could see that being an issue. I also thought the Samson S-Convert would alleviate this, but it doesn't..

To me, it seems like a ground loop. But why would the ground loop only exist with certain (Pro Audio) devices?? I know I can buy a device for ground loops, but I really do not want a ton of boxes & cables. Ideally, if there is an alternative to the Samson S-Convert (like he ART or Rolls) that does the RCA>XLR, boosts the signal, AND fixes ground loops, I would be fine with that. But to have Receiver, Samson box, EQ, Ground Loop killer, Pro Amp, all with jumbles of RCA & XLR cables, I fear that would have problems no matter what..

In the event it is indeed a ground loop, I have seen 3 main types of Isolators-

1.) One that goes onto the 3 prong plug into the wall.
2.) One that goes in-line with the RCA's, and is also powered.
3.) One that goes in-line with the RCA's but is passive, not powered.

Which one of those would fix this? I was thinking the one for the wall plug, since it is specific to 2 devices being hooked up. But unsure if the hum/buzz could have to do with Amp & EQ wanting the Balanced XLR as a connection.

I also think I tried another troubleshoot, and I will try this again tomorrow just in case. I think I also hooked up the Yamaha Sub RCA to the Samson S-Convert by itself, and it did not buzz until the amp was also hooked up to it.

Hoping you can help! Appreciation in advance!!
 
M

massacre

Audioholic Intern
are you using the trigger wire from the Yamaha?
 
P

PENG

Audioholic Overlord
Hello everyone. Hoping someone can help me solve an issue I am having. I am expanding my sound system in my den at home. Mostly with stuff I already own, while adding a few new items. I have done a lot of troubleshooting already, and wanted some guidance before I started throwing more money and parts at the problem. This forum has always been a big help, even just from searching, and resulted in a few of the items I am now integrating into my home system. I know a lot of this stuff is Old School, but I really prefer the older stuff in most cases.

So I am hooking up a Crown XLS1000 amp to power 2 separate 10" vented subs I am building. I know, Crown is mostly Pro Audio oriented, but it had RCA inputs. However, I overlooked the input sensitivity, which is adjustable on all other Crown lines with RCA inputs. But not this one, of course. Oversight that I regretted. And so hum or no hum, the output was whisper quiet. So I bought a Samson S-Convert (basically the same as Rolls Promatch & ART Cleanbox) so it would not only boost the signal, but could also convert from RCA to XLR. So in the future I could upgrade to any Pro Audio amp.

In addition, my Yamaha RX-V2095 (from ~2001, LOVE IT!) is 5.1, and also has a preamp out/in loop for an external EQ or processor, or even amps for all channels. So I wanted to utilize the out/in loop to hook up a Behringer DSP8024 EQ I have had for years, from back when I DJ'ed weddings & events. This does not have RCA in/out, only the XLR. But I already had some XLR>RCA cables, plus I now have the Samson that boosts & converts from RCA to XLR.

So that's the goals. Hook up the EQ with the Samson S-Convert on the EQ loop, and hook up the Crown XLS1000 to power the two subs I am building. Now.. Here is the situation:

When ever I hook up either the Crown or the Behringer to my Yamaha, I get a very bad hum/buzz from the speakers. I have done the following troubleshooting:

~Tried using the sub out RCA as well as the EQ out/in RCAs, to either the Crown or Behringer. All combinations get the hum/buzz from the speakers connected to the Yamaha.
~I tried with & without the Samson S-Convert in line, hum no matter what.
~I tried plugging the power for the 2 Pro items to different power strips, as well as different outlets. No changes.
~To reduce variables, I even went straight from sub out on Yamaha to the Crown RCA in, without even speakers connected to the Crown, no EQ or Samson S-Convert. and still had hum on the speakers connected to the Yamaha.
~With the RCAs hooked up on the Yamaha side, but to nothing else on the other end, NO HUM at all!
~I then took a spare receiver from a different room, and hooked that up with RCA from the Yamaha sub out to an audio input on the spare receiver, and there was no hum.

So the hum only exists when either of the Pro Audio items are connected, in any way. I know they mostly desire Balanced XLR. But the Crown has RCA inputs, so I don't see why that's an issue. If I got the hum when using the XLR>RCA adapter cables, then I could see that being an issue. I also thought the Samson S-Convert would alleviate this, but it doesn't..

To me, it seems like a ground loop. But why would the ground loop only exist with certain (Pro Audio) devices?? I know I can buy a device for ground loops, but I really do not want a ton of boxes & cables. Ideally, if there is an alternative to the Samson S-Convert (like he ART or Rolls) that does the RCA>XLR, boosts the signal, AND fixes ground loops, I would be fine with that. But to have Receiver, Samson box, EQ, Ground Loop killer, Pro Amp, all with jumbles of RCA & XLR cables, I fear that would have problems no matter what..

In the event it is indeed a ground loop, I have seen 3 main types of Isolators-

1.) One that goes onto the 3 prong plug into the wall.
2.) One that goes in-line with the RCA's, and is also powered.
3.) One that goes in-line with the RCA's but is passive, not powered.

Which one of those would fix this? I was thinking the one for the wall plug, since it is specific to 2 devices being hooked up. But unsure if the hum/buzz could have to do with Amp & EQ wanting the Balanced XLR as a connection.

I also think I tried another troubleshoot, and I will try this again tomorrow just in case. I think I also hooked up the Yamaha Sub RCA to the Samson S-Convert by itself, and it did not buzz until the amp was also hooked up to it.

Hoping you can help! Appreciation in advance!!
This is a very long post that will take some time understand the details. For now, suffice to say someone is also having issue with connecting his AVR (Marantz I think) to his XLS 1502, except he's getting a high pitch noise and it's there even without the Crown power cord connected so I guess it is a different issue but could still be related.

In your case, are you only getting the hum with the Crown powered up? How about if the signal wire/interconnects are connected but the power cord not connected to the outlet? I am asking this only for troubleshooting purposes.
 
lovinthehd

lovinthehd

Audioholic Slumlord
Is the rest of your gear connected to same outlet? Does the other gear used a grounded plug (three prong)?
 
E

ENDEE666

Audiophyte
Is the rest of your gear connected to same outlet? Does the other gear used a grounded plug (three prong)?
I tried 2 different surge protectors, as well as 2 different outlets, and that didn't change the hum..

However, I think I have isolated the issue! Pun intended! I saw an article online about using items like the Ebtech Hum X which goes in between the power cable & the outlet or power strip. The article mentioned that as a test (not long term) you can use a "cheater plug" that is used for plugging 3 prong grounded plugs into 2 prong outlets, thus taking the ground loop out of the mix. Well, IT WORKED!! Almost eliminated the hum, just left an extremely faint buzz. The remaining buzz would not be heard on a sub, and could very well be eliminated the rest of the way with a proper ground loop isolator.

So the remaining questions are the best solution, now that the problem is identified. Those Hum X are $79 each. Are there less expensive alternatives that work as well? Either way, would I need two? Or can I just do one between a dedicated power strip and the wall, and plug only the Crown & Behringer into that strip? Lastly, is there any other ways I should look into to remedy the ground loop?

Quite relieved that it isn't a defective amp or EQ..
 
TLS Guy

TLS Guy

Audioholic Slumlord
I tried 2 different surge protectors, as well as 2 different outlets, and that didn't change the hum..

However, I think I have isolated the issue! Pun intended! I saw an article online about using items like the Ebtech Hum X which goes in between the power cable & the outlet or power strip. The article mentioned that as a test (not long term) you can use a "cheater plug" that is used for plugging 3 prong grounded plugs into 2 prong outlets, thus taking the ground loop out of the mix. Well, IT WORKED!! Almost eliminated the hum, just left an extremely faint buzz. The remaining buzz would not be heard on a sub, and could very well be eliminated the rest of the way with a proper ground loop isolator.

So the remaining questions are the best solution, now that the problem is identified. Those Hum X are $79 each. Are there less expensive alternatives that work as well? Either way, would I need two? Or can I just do one between a dedicated power strip and the wall, and plug only the Crown & Behringer into that strip? Lastly, is there any other ways I should look into to remedy the ground loop?

Quite relieved that it isn't a defective amp or EQ..
A ground loop is always a resistance between grounds. So among your equipment list which units have three pin plugs and which 2?

Also what is connected to your receiver? In particular which units have Ethernet and or cable connections connections?

What do you use for TV? Is it cable or satellite.?

I would give you an example of how a ground loop would occur. If you have Ethernet and or cable for instance which has a different potential to your house ground, (common) and your receiver is two pin, but you Crown is has three pin, then you have your classic ground loop and hum.
 
E

ENDEE666

Audiophyte
A ground loop is always a resistance between grounds. So among your equipment list which units have three pin plugs and which 2?

Also what is connected to your receiver? In particular which units have Ethernet and or cable connections connections?

What do you use for TV? Is it cable or satellite.?

I would give you an example of how a ground loop would occur. If you have Ethernet and or cable for instance which has a different potential to your house ground, (common) and your receiver is two pin, but you Crown is has three pin, then you have your classic ground loop and hum.
I have Verizon Fios, cable.

Here is my relevant chain of connections:
Coax cable input from main splitter of the house split again in Den to Fios cable box & to router.
Cable box to LED TV via HDMI, then audio from TV to Receiver via Fiber/Optical.
Then I was going from Receiver RCA outs (tried sub/LFE and Preamp out/in loop) to RCA in on either Crown or Behringer. Regardless if the Samson S-Convert was in the loop or not, once the Crown OR Behringer got connected, the hum arrived.

No Ethernet in the mix, things are connected via wifi since the router is only a few feet away, and I have the gigabit internet.

2-Prong items - TV (plugged directly to outlet), Fios cable box (does have an in-line transformer box like a laptop charger, and is plugged to surge protector), Yamaha receiver (plugged into surge protector)

3-Prong items - Crown amp, Behringer EQ.

So the 2 Pro Audio items are the only 3-Prong, grounded items. So that makes sense. And further establishes the noise is on the power/plug side, not necessarily on the signal or cables. Right?

So, since the 3>2 prong adapter worked in my test, what is the best & most cost effective way to resolve this? Things like the Hum X? If so, what other options are there for less than $80 a pop? Unless I can get away with just one of those between the surge protector & the wall outlet? I would be fine with an $80 solution, but would rather not a $160 solution.
 
TLS Guy

TLS Guy

Audioholic Slumlord
I have Verizon Fios, cable.

Here is my relevant chain of connections:
Coax cable input from main splitter of the house split again in Den to Fios cable box & to router.
Cable box to LED TV via HDMI, then audio from TV to Receiver via Fiber/Optical.
Then I was going from Receiver RCA outs (tried sub/LFE and Preamp out/in loop) to RCA in on either Crown or Behringer. Regardless if the Samson S-Convert was in the loop or not, once the Crown OR Behringer got connected, the hum arrived.

No Ethernet in the mix, things are connected via wifi since the router is only a few feet away, and I have the gigabit internet.

2-Prong items - TV (plugged directly to outlet), Fios cable box (does have an in-line transformer box like a laptop charger, and is plugged to surge protector), Yamaha receiver (plugged into surge protector)

3-Prong items - Crown amp, Behringer EQ.

So the 2 Pro Audio items are the only 3-Prong, grounded items. So that makes sense. And further establishes the noise is on the power/plug side, not necessarily on the signal or cables. Right?

So, since the 3>2 prong adapter worked in my test, what is the best & most cost effective way to resolve this? Things like the Hum X? If so, what other options are there for less than $80 a pop? Unless I can get away with just one of those between the surge protector & the wall outlet? I would be fine with an $80 solution, but would rather not a $160 solution.
If I understand this correctly, then the only grounds are the Crown amp and the Behringer EQ and this FIOS system.

If that is so, then the problem has to be resistance to ground in the FIOS system and the ground of the Crown amp and or the Behringer EQ. If you can be certain those are the only grounds then there is your problem.

Forget expensive solutions like Hum X. Those sort of approaches are useless. You have to get your grounds at the same potential or only have one ground. There are no other solutions.

So before I go any further I need you to disconnect your system from the FIOS system. So disconnect all COAX connections to that system and see if the hum stops.

Then put the cheater plug on the Behringer with and without the FIOS connected to your system. Then we can see where the resistances to ground are originating.

I am doing a big install for someone out of town, and will not be back to my hotel room until late this evening. I will have this laptop with me for the install so I may get a chance to reply. This laptop has programs on it for the install, so I might get a chance to respond, but don't bank on it. But I will get back to you.

If it does then we can explore how to go about fixing your problem.
 
highfigh

highfigh

Audioholic Overlord
Disconnect the FIOS cable at the demarcation point and if the hum stops, call Verizon to tell them to fix their installation.

BTW- ALL of the equipment connected to the FIOS cabling is involved in the system that hums, so check all of the terminations and make sure they're tightly connected.
 
P

PENG

Audioholic Overlord
I have Verizon Fios, cable.

Here is my relevant chain of connections:
Coax cable input from main splitter of the house split again in Den to Fios cable box & to router.
Cable box to LED TV via HDMI, then audio from TV to Receiver via Fiber/Optical.
Then I was going from Receiver RCA outs (tried sub/LFE and Preamp out/in loop) to RCA in on either Crown or Behringer. Regardless if the Samson S-Convert was in the loop or not, once the Crown OR Behringer got connected, the hum arrived.

No Ethernet in the mix, things are connected via wifi since the router is only a few feet away, and I have the gigabit internet.

2-Prong items - TV (plugged directly to outlet), Fios cable box (does have an in-line transformer box like a laptop charger, and is plugged to surge protector), Yamaha receiver (plugged into surge protector)

3-Prong items - Crown amp, Behringer EQ.

So the 2 Pro Audio items are the only 3-Prong, grounded items. So that makes sense. And further establishes the noise is on the power/plug side, not necessarily on the signal or cables. Right?

So, since the 3>2 prong adapter worked in my test, what is the best & most cost effective way to resolve this? Things like the Hum X? If so, what other options are there for less than $80 a pop? Unless I can get away with just one of those between the surge protector & the wall outlet? I would be fine with an $80 solution, but would rather not a $160 solution.
Wow, no wonder you have the typical ground loop hum. In a way, this is good because at least now you can just concentrated on dealing with one issue, namely ground loop. I agreed with TLSGuy that $75 for the hum X is not the right solution. It is better to pin point the culprit and go from there..
 
E

ENDEE666

Audiophyte
If I understand this correctly, then the only grounds are the Crown amp and the Behringer EQ and this FIOS system.

If that is so, then the problem has to be resistance to ground in the FIOS system and the ground of the Crown amp and or the Behringer EQ. If you can be certain those are the only grounds then there is your problem.

Forget expensive solutions like Hum X. Those sort of approaches are useless. You have to get your grounds at the same potential or only have one ground. There are no other solutions.

So before I go any further I need you to disconnect your system from the FIOS system. So disconnect all COAX connections to that system and see if the hum stops.

Then put the cheater plug on the Behringer with and without the FIOS connected to your system. Then we can see where the resistances to ground are originating.

I am doing a big install for someone out of town, and will not be back to my hotel room until late this evening. I will have this laptop with me for the install so I may get a chance to reply. This laptop has programs on it for the install, so I might get a chance to respond, but don't bank on it. But I will get back to you.

If it does then we can explore how to go about fixing your problem.
I appreciate your help and urgency to help me out, that's really impressive, thank you!! Worth mentioning that I am not under any deadline or anything, especially since the cheater plug has given me a temporary solution. So I wouldn't want my problem to interfere with you completing your install, but the help is definitely appreciated and welcomed!

Actually, the Fios power cable does not have a 3-Prong grounded plug. But about halfway inline along the power cable it has a rectangle box transformer, much like laptops usually have. So the power cable (2-Prong) goes to that transformer box, and then the wire goes from the transformer box to the Fios cable box and has a small pin/barrel plug on that end that goes into the Fios cable box.. The Fios router's power cable is also plugged into the same power strip, and is also a 2-Prong plug. For the router, the transformer box is right on the plug where it goes into the wall/strip, like old AC Adapters with a block on the plug.

So the only 3-Prong grounded devices are the 2 Pro Audio items, Crown & Behringer EQ, and both introduce the noise as soon as they are connected to the rest of the equipment in any way.

However, I will try taking the Fios equipment (both since they both have coax) out of the mix, and see what happens as they are each introduced, and if that makes any changes in hum or no hum.

Again, very much appreciated! Especially if we find a better final solution than a $80 plug adapter like the Hum X.
 
lovinthehd

lovinthehd

Audioholic Slumlord
Where I last lived the cable service had just created their own ground rather than using the house's ground I eventually figured out. I just used a cheater plug for a while and took my chances :) (there are possibilities of getting a shock in the right circumstances). Might see if the cable service did the same to you....
 
TLS Guy

TLS Guy

Audioholic Slumlord
I appreciate your help and urgency to help me out, that's really impressive, thank you!! Worth mentioning that I am not under any deadline or anything, especially since the cheater plug has given me a temporary solution. So I wouldn't want my problem to interfere with you completing your install, but the help is definitely appreciated and welcomed!

Actually, the Fios power cable does not have a 3-Prong grounded plug. But about halfway inline along the power cable it has a rectangle box transformer, much like laptops usually have. So the power cable (2-Prong) goes to that transformer box, and then the wire goes from the transformer box to the Fios cable box and has a small pin/barrel plug on that end that goes into the Fios cable box.. The Fios router's power cable is also plugged into the same power strip, and is also a 2-Prong plug. For the router, the transformer box is right on the plug where it goes into the wall/strip, like old AC Adapters with a block on the plug.

So the only 3-Prong grounded devices are the 2 Pro Audio items, Crown & Behringer EQ, and both introduce the noise as soon as they are connected to the rest of the equipment in any way.

However, I will try taking the Fios equipment (both since they both have coax) out of the mix, and see what happens as they are each introduced, and if that makes any changes in hum or no hum.

Again, very much appreciated! Especially if we find a better final solution than a $80 plug adapter like the Hum X.
The issue with systems like FIOS, is not the AC plug, but the grounding of the signal cable.

These systems are notorious for creating ground loops. So the cause of your problem is almost certainly related to FIOS.

So that is what we need details of. So please do the tests I requested in the previous post.
 
highfigh

highfigh

Audioholic Overlord
The issue with systems like FIOS, is not the AC plug, but the grounding of the signal cable.

These systems are notorious for creating ground loops. So the cause of your problem is almost certainly related to FIOS.

So that is what we need details of. So please do the tests I requested in the previous post.
It's not only ground loops, they sometimes have line amplifiers that are leaky, so voltage reaches the equipment in the buildings.
 
TLS Guy

TLS Guy

Audioholic Slumlord
It's not only ground loops, they sometimes have line amplifiers that are leaky, so voltage reaches the equipment in the buildings.
Yes, and that as well. Direct TV is the worst. That hums whatever you do. And it is in their contract now that you have to put up with hums and buzzes!
 
highfigh

highfigh

Audioholic Overlord
Yes, and that as well. Direct TV is the worst. That hums whatever you do. And it is in their contract now that you have to put up with hums and buzzes!
Or, install DC blocking device, which isn't terribly expensive.

I helped a friend install AV & network cabling/equipment in a Chicago apartment and when the den system was turned on for the first time, we heard hum and saw noise bars on the TV, so I installed a DC block on the cable to stop it. A couple of weeks later, the client's wife called to tell my friend that she heard hum and saw noise bars after a Comcast installer had been there, so he asked if she could see a small barrel-shaped piece on the desk or in the cabinet- sure enough, the installer had removed it because they don't want anything other than their parts on the cables. It obviously didn't matter that it had no hum before he showed up, but he stuck to Comcast's rules.
 
lovinthehd

lovinthehd

Audioholic Slumlord
Yes, and that as well. Direct TV is the worst. That hums whatever you do. And it is in their contract now that you have to put up with hums and buzzes!
Altho I recently terminated D*, their installation here was fine. They installed it using the house ground after I moved in, no noises. Just a bloated bill with lots of bad tv channels at the end earlier this year, much happier without them vs using various internet services, and now that I've recently been able to get decent internet speed especially so.
 
little wing

little wing

Senior Audioholic
Yes, and that as well. Direct TV is the worst. That hums whatever you do. And it is in their contract now that you have to put up with hums and buzzes!
Wow, just wow. I guess I'm lucky, I don't have hums in my system with DirecTV. But picture does periodically freeze for a few seconds.
 
S

Speedskater

Senior Audioholic
Standard troubleshooting procedure:
  • unplug everything. AC power, interconnects, cable TV & internet.
  • use one big outlet strip. no power conditioners.
  • amplifier. connect loudspeaker and AC power. does it hum?
  • source or adapter component. connect to amplifier and AC power. does it hum?
  • continue adding one component or cable at a time, until it hums.
 

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