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Post by doc1963 on Jul 10, 2017 14:02:26 GMT -5
I agree with Nick. Your XMC-1 is likely not the issue. In your first post, you mention that when connected to your A-100, your speakers are dead quiet. In all of the resulting posts, you never mention the make and model of your new 5 channel amp. Is it a "pro" amp or a standard consumer grade (intended for home use) amp like the A-100...?
If it's a "pro" amp, have you tried XLR balanced connections between the XMC-1 and the amp...? I've seen many pro amps in my days that have noisy RCA inputs and, if so, that could possibly be the root of your problem.
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Post by Deleted on Jul 10, 2017 14:08:07 GMT -5
Here's a Sherlock Holmes idea- take the system to your neighbors house, pour a couple cold ones for the hospitality.
Cheaper than shipping charges. (unless you pour single malt like my neighbor...hahaha)
"Is there anything I can do to test it? I have a digital voltage meter if that helps."
1) Set the VOM to AC volts
2) measure between ground & neutral (the wide slot)
3) measure with everything unplugged & "off"
4) turn everything "on" measure again. (plugged in of course)
What were the readings?
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Post by alucard on Jul 10, 2017 14:38:34 GMT -5
I agree with Nick. Your XMC-1 is likely not the issue. In your first post, you mention that when connected to your A-100, your speakers are dead quiet. In all of the resulting posts, you never mention the make and model of your new 5 channel amp. Is it a "pro" amp or a standard consumer grade (intended for home use) amp like the A-100...? If it's a "pro" amp, have you tried XLR balanced connections between the XMC-1 and the amp...? I've seen many pro amps in my days that have noisy RCA inputs and, if so, that could possibly be the root of your problem. It's a 5ch D-Sonic amp. The same issue existed with 3 other amps too. The A-100 has 2 prong plug whereas the D-Sonic and 3 others have three....if that matters |
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Post by alucard on Jul 10, 2017 14:42:52 GMT -5
Here's a Sherlock Holmes idea- take the system to your neighbors house, pour a couple cold ones for the hospitality. Cheaper than shipping charges. (unless you pour single malt like my neighbor...hahaha) "Is there anything I can do to test it? I have a digital voltage meter if that helps." 1) Set the VOM to AC volts 2) measure between ground & neutral (the wide slot) 3) measure with everything unplugged & "off" 4) turn everything "on" measure again. (plugged in of course) What were the readings? Thanks, texzick. For #2 I'll measure the outlet, for #4 where am I measuring - a different outlet on same circuit? Edit - results in NEW INFO post below |
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Post by leonski on Jul 10, 2017 16:04:45 GMT -5
Does turning the TV on or OFF cause a change in the problem?
My Panasonic Plasma was an RFI nightmare.
Not so, my new OLED display.
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Post by alucard on Jul 10, 2017 16:24:36 GMT -5
Does turning the TV on or OFF cause a change in the problem? My Panasonic Plasma was an RFI nightmare. Not so, my new OLED display. No. I took that out of the equation. |
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Post by Axis on Jul 10, 2017 16:29:46 GMT -5
Just being funny here, but have you made a hat out of tinfoil to see if that helps ?  |
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Post by alucard on Jul 10, 2017 16:30:00 GMT -5
NEW INFO below that may help isolate the cause or make it as clear as mud. 1. When I did a quick test with the two-prong plug I did not screw it down to the receptacle - results were no buzz from speaker. Today, I found when it is screwed down the speaker buzz comes back. 2. I measured ground to neutral voltage at the outlet: unplugged/off 121.1v and 120.9v with everything plugged in and turned on. 3. I tested several outlets and all came back with "correct"  |
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Post by leonski on Jul 10, 2017 18:17:38 GMT -5
Neutral to Ground @120vac+? They should be very close to the same potential. Probably not more than 2 or 3 volts different.
Sure you got neutral to ground?
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DYohn
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Post by DYohn on Jul 10, 2017 18:20:37 GMT -5
Your problem is not likely a house wiring issue, it is a noise on the ground plane issue. By grounding the adapter you created the same wiring as just using the three prongs of your cable.
And yes, neutral to ground should be close to zero potential. Hot to ground should be ~120VAC.
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Post by alucard on Jul 10, 2017 18:44:32 GMT -5
Neutral to Ground @120vac+? They should be very close to the same potential. Probably not more than 2 or 3 volts different. Sure you got neutral to ground? Your problem is not likely a house wiring issue, it is a noise on the ground plane issue. By grounding the adapter you created the same wiring as just using the three prongs of your cable. And yes, neutral to ground should be close to zero potential. Hot to ground should be ~120VAC. Whoopsie, yes hot to ground is 120, neutral to ground is .001 Also, are there any known solutions or just need an electrician take a look? |
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Post by alucard on Jul 10, 2017 20:28:24 GMT -5
I'm going to try the CMX-2. I tried it couple years ago for this same issue but only plugged the amp into it if I remember correctly. This time I'll test both amp and preamp. If it ships tomorrow I should have it on Friday.
Just want to say thanks to everyone who provided input here. I appreciate your support and I'll let you know how the CMX goes.
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hemster
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Post by hemster on Jul 10, 2017 20:35:10 GMT -5
I'm going to try the CMX-2. I tried it couple years ago for this same issue but only plugged the amp into it if I remember correctly. This time I'll test both amp and preamp. If it ships tomorrow I should have it on Friday. Just want to say thanks to everyone we who provided input here. I appreciate your support and I'll let you know how the CMX goes. The preamp is more susceptible to noise, hum, etc. Purely because most amps worth their salt have decent grounding. But being that they deal with low voltages, this is not necessarily the case with all preamps. Good luck and keep us posted. We're all here to help you through this.  |
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Post by leonski on Jul 10, 2017 20:43:07 GMT -5
Any way at all to hook up everything with BALANCED cables?
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Post by alucard on Jul 10, 2017 20:56:27 GMT -5
Any way at all to hook up everything with BALANCED cables? Not at the moment. I tested XLRs (monoprice) in the past when I first had this issue a couple years ago and they did not help. I stopped looking for a solution after I added isomax transformers. Now with the new amp I want to clean this up, reduce clutter, etc. and that is what spurred this round of hunting. |
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Post by bluemeanies on Jul 11, 2017 6:10:06 GMT -5
Are you using shielded cables?
Just asking...sorry if it's a repeat question.
Keep us up dated
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Post by Deleted on Jul 11, 2017 9:35:53 GMT -5
Sorry I could not get back yesterday.
Our intent is to check the wall plug you are using for power.
Everything in the system is referenced to 0 volts- circuit ground in electronics- and need to know if there is voltage floating on that reference to chassis ground.
1) check neutral to ground with equipment plugged in, but "off"
2) Then unplug everything, take neutral to ground readings again
3) plug in everything, turn "on" and check a third time.
Pls use a low setting on your meter, using 200vac setting may not show what we are looking for.
As I said on page 1, if there is voltage between the neutral- ground, there is a wiring problem. In a perfect world that reading should be 0 volts, but in reality, sometime there will be a small voltage there. The question is how much voltage. If there is 2-2.5 volts or more, you need a new line run because you can not find any tap offs someone may have added after the circuit was installed, or the wire gauge is undersized for the load it carries. If we are using that circuit to run a light or power tool, it's not a problem, but with electronics it's a big deal.
If you think about it, digital is 0 volts off, 5 volts on, a floating voltage of 2.5 volts or more on the reference will drive the processor nuts, causing intermittent problems.
In audio, a floating voltage on reference can be audible noise.
After I got the XPA-5, I installed a new 20 amp breaker & 12 gauge 3-wire to the plug because I also run a rear projection tv monitor off it.
The last thing I want is a supply line voltage fluctuating due to high current draw.
That line is called an "isolated line" because nothing is tapped off and only goes to one service outlet. In the business world that circuit will have an orange plug.
A dedicate line is one that has a dedicated hot (breaker) but the neutral-ground is shared with another circuit.
Most houses have all shared lines, meaning there is up to 3 outlets using one breaker & wires.
Usually shared lines are not an issue until there is high current draw or something with inductive load is spiking the line as the coil field collapses & re-energizes.
Busy day today, but I'll check back
Jeff
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Post by alucard on Jul 11, 2017 10:37:31 GMT -5
Sorry I could not get back yesterday. Our intent is to check the wall plug you are using for power. Everything in the system is referenced to 0 volts- circuit ground in electronics- and need to know if there is voltage floating on that reference to chassis ground. 1) check neutral to ground with equipment plugged in, but "off" 2) Then unplug everything, take neutral to ground readings again 3) plug in everything, turn "on" and check a third time. Pls use a low setting on your meter, using 200vac setting may not show what we are looking for. As I said on page 1, if there is voltage between the neutral- ground, there is a wiring problem. In a perfect world that reading should be 0 volts, but in reality, sometime there will be a small voltage there. The question is how much voltage. If there is 2-2.5 volts or more, you need a new line run because you can not find any tap offs someone may have added after the circuit was installed, or the wire gauge is undersized for the load it carries. If we are using that circuit to run a light or power tool, it's not a problem, but with electronics it's a big deal. If you think about it, digital is 0 volts off, 5 volts on, a floating voltage of 2.5 volts or more on the reference will drive the processor nuts, causing intermittent problems. In audio, a floating voltage on reference can be audible noise. After I got the XPA-5, I installed a new 20 amp breaker & 12 gauge 3-wire to the plug because I also run a rear projection tv monitor off it. The last thing I want is a supply line voltage fluctuating due to high current draw. That line is called an "isolated line" because nothing is tapped off and only goes to one service outlet. In the business world that circuit will have an orange plug. A dedicate line is one that has a dedicated hot (breaker) but the neutral-ground is shared with another circuit. Most houses have all shared lines, meaning there is up to 3 outlets using one breaker & wires. Usually shared lines are not an issue until there is high current draw or something with inductive load is spiking the line as the coil field collapses & re-energizes. Busy day today, but I'll check back Jeff Thanks for the response. I will retest neutral to ground properly this time. |
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Post by Deleted on Jul 11, 2017 10:39:33 GMT -5
[/quote]Not at the moment. I tested XLRs (monoprice) in the past when I first had this issue a couple years ago and they did not help. I stopped looking for a solution after I added isomax transformers. Now with the new amp I want to clean this up, reduce clutter, etc. and that is what spurred this round of hunting.[/quote]
Good idea to use iso xformers, usually not necessary. but did it work??? Was the noise eliminated with it?
That is kinda important information.
If it did fix the problem, install a 20 amp isolated line and be done with it.
I ordered a custom made center tap 2400 watt Toroidal that gives me 60 vac + 60 vac to the hot side and it has saved my electronics numerous times because it stores voltage for a short time and it removes spikes. The power is constantly browning out here during storms.
I lost 3 pieces of electronics before the iso xformer & none since. I now use a UPS for my lower power draw equipment- DTV, HTPC & UMC200.
I realize I'm anal about line voltage, thus installed an isolated circuit before I hooked up the XPA. I'm tired of having to buy equipment twice due to power problems.
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Post by alucard on Jul 11, 2017 10:48:55 GMT -5
Good idea to use iso xformers, usually not necessary. but did it work??? Was the noise eliminated with it? That is kinda important information. If it did fix the problem, install a 20 amp isolated line and be done with it. I ordered a custom made center tap 2400 watt Toroidal that gives me 60 vac + 60 vac to the hot side and it has saved my electronics numerous times because it stores voltage for a short time and it removes spikes. The power is constantly browning out here during storms. I lost 3 pieces of electronics before the iso xformer & none since. I now use a UPS for my lower power draw equipment- DTV, HTPC & UMC200. I realize I'm anal about line voltage, thus installed an isolated circuit before I hooked up the XPA. I'm tired of having to buy equipment twice due to power problems. I bought the jenson isomax transformer to resolve speaker buzz and yes that worked well. They did not fix amp buzz nor were they supposed to. leonski suggested to look at Power Line Isolation Transformers. I'll try the CMX-2 later this week when it's delivered. If that does not help I will (as of this writing) get an power line iso transformer...but pending more research. Initial findings revealed this: www.tripplite.com/isolator-series-120v-1000w-isolation-transformer-based-power-conditioner-4-outlets~IS1000/My goal here is to resolve speaker buzz without the use of jensen isomax (and 2x the number of RCA cables. ex. 10 instead of 5 for 5ch system), and resolve amp buzz that I thought went away but is there and verified last couple days. |
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