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Post by newandlost on Nov 14, 2023 14:01:08 GMT -5
I recently upgraded my processor from an old Marantz AV7005 pre-pro to an Arcam AV41. On the Marantz, I was always using unbalanced cables to my Emotiva XPA-5, but when I upgraded I moved to XLR connections. Now, when I turn the system off, I am getting strange noises out of one of the surround channels, which I have been able to trace back to an amplifier channel closest to the power cord. To do this I swapped XLR inputs into the amp and then swapped speaker cables to make sure it wasn't noise picked up after the amp. Has anyone else experienced this?
Additionally, I am getting a faint helicopter sound on my subwoofers which feels indicative of a ground loop issue in the system (which may or may not be unrelated). The chirping sounds occur even when the subs are disconnected, so I think I am fighting two separate issues here. Both subwoofers are the Emotiva XS15s and they worked flawlessly with unbalanced inputs, but moving those to balanced connections has created more issues.
Any advice is appreciated.
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Post by 405x5 on Nov 16, 2023 12:18:24 GMT -5
I recently upgraded my processor from an old Marantz AV7005 pre-pro to an Arcam AV41. On the Marantz, I was always using unbalanced cables to my Emotiva XPA-5, but when I upgraded I moved to XLR connections. Now, when I turn the system off, I am getting strange noises out of one of the surround channels, which I have been able to trace back to an amplifier channel closest to the power cord. To do this I swapped XLR inputs into the amp and then swapped speaker cables to make sure it wasn't noise picked up after the amp. Has anyone else experienced this? Additionally, I am getting a faint helicopter sound on my subwoofers which feels indicative of a ground loop issue in the system (which may or may not be unrelated). The chirping sounds occur even when the subs are disconnected, so I think I am fighting two separate issues here. Both subwoofers are the Emotiva XS15s and they worked flawlessly with unbalanced inputs, but moving those to balanced connections has created more issues. Any advice is appreciated. Did you swap to XLR before changing out the processor? I mean the processor swap was the big ticket how do you know the new processor isn’t the source of the noise? |
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Post by Zombie on Nov 16, 2023 14:30:49 GMT -5
Did you by chance flip the switch on the back of the amp from unbalanced to balanced?
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Post by newandlost on Nov 16, 2023 14:45:06 GMT -5
405x5 - Thank you for the feedback.
The helicopter sub issue does appear to be the new processor, but the strange power down noises appear to come from the amp. When I put back in the Marantz with all balanced connections the subs work as expected but the strange power down sounds did NOT go away.
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Post by newandlost on Nov 16, 2023 14:46:28 GMT -5
Zombie - Thanks for your reply.
Yes, the amplifier switches are all set to balanced inputs.
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Post by 405x5 on Nov 16, 2023 15:19:21 GMT -5
405x5 - Thank you for the feedback. The helicopter sub issue does appear to be the new processor, but the strange power down noises appear to come from the amp. When I put back in the Marantz with all balanced connections the subs work as expected but the strange power down sounds did NOT go away. If the power down sounds are not present during normal up and running operation I would not lose any sleep over that…… I’ve had a few amps. over the years, where power down noises were a normal consequence of their design, and we’re dead quiet during operation. I would review some of the basics like the condition of power strips and power cords to make sure they’re all in good shape if your power strips are old, one of them, could’ve taken a shot over the years from a surge you can replace that. The other thing I would do is determine where the loads are going. In other words see if you can get your processor and amplifier on a separate breaker from your subwoofers. you don’t wanna have all your load on one breaker for a number of reasons. |
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Post by leonski on Nov 17, 2023 23:11:03 GMT -5
I'm having trouble 'hearing' the problem.....?
Some kind of High Frequency 'CHIRP' upon shutdown? Tweeters don't like that......
Experiment with shutdown order.....and with the level turned to 'Zero' for some tests.....
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Post by vcautokid on Nov 18, 2023 0:07:20 GMT -5
I am sure you are doing this already, but just in case. The manual of arms is always. Turn on the source 1st, then the preamplifier/proc, and last the power amplifier. Then the reverse order when shutting down after turning down the volume very low or to zero.
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Post by newandlost on Nov 26, 2023 22:04:35 GMT -5
Sorry for the late replies and thank you to everyone for your help. I returned the Arcam AV41 and got an Anthem AVM70 and there are no chirps from speakers on shutdown, and no issues with the subs anymore. Additionally, I added a Panamax power conditioner (I know some people say they do nothing) but either that or the Anthem seems to have fixed my issues. I read online about some "questionable decisions" Arcam made with their ground design and it seems like maybe that's what it was for me... Again, thanks to everyone who weighed in and helped out!
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Post by ttocs on Nov 26, 2023 22:50:26 GMT -5
Additionally, I added a Panamax power conditioner (I know some people say they do nothing) . . . I have two Panamax M5400-PM. They don't do nothing. They can't stop all the bad stuff, but they don't do nothing. In my neighborhood, from 2013 when I moved in until about two years ago, the voltage was at around 128V mostly during the days and a little less at night. But it would fluctuate a lot and drop down to less than 115V. So the Panamax's would adjust the voltage accordingly. Fluctuating voltage isn't so bad compared to other stuff that's happened around here. So this stopped happening a couple years ago and was replaced with serious undervolt conditions that would pop up now and then, one time it was at 45V for over four hours. All the while the Panamax's would keep the voltage in range when it could, and stop passing under/over-volts when these occurred. During this past year none of this has happened, but the power will blink off/on/off/on/off/on, but this hasn't happened since early Summer, luckily? or maybe the power company fixed it? When the Panamax relays start clicking repeatedly, I know something bad is happening! |
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Post by leonski on Nov 26, 2023 23:32:43 GMT -5
MY Panamax DOES do something. When first installed? ALL the 'snow' on the 36" direct view TV....a 200lb Panasonic....simply Disappeared. The picture by that means
was more saturated (color) and better blacks.
Sound was also improved. I had to readjust the speakers for better image and clarity.
Part of the improvement I write off to the small (only 400va) Isolation Transformer, used for all low power parts of the system.....
Amps do NOT like the Panamax. Don't know why, but best sound is plugged straight into the wall.....on an exclusive 20 amp circuit.
Line voltage at my location is right at 119.5vac.....But can droop to around 115 in the max demand times of summer. At which time I
begin to shut stuff off and disconnect....
Other features? Well it Does have nearly useless volt and amp meters. But it WILL shut off all the outlets when voltage drops below
95vac or goes above about 135vac....It has done this several times in the 15 to 20 years I've owned this device....which at time of purchase
was a (gasp!) 1000$ plus.....
But NO voltage adjust......
Panamax will NOT spring for a schematic. I want to replace the MOVs, the only 'consumable' part while if space, improving the protection....
NO clicking relays. Ever.
I'd LOVE some detail about 'questionable ground decisions'.....
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Post by ttocs on Nov 26, 2023 23:50:54 GMT -5
But NO voltage adjust...... Which model? The M5400-PM adjusts to keep voltage between 115V and 125V. If the incoming voltage is outside of the range then the M5400-PM adjusts to keep the voltage to connected devices within that range. Agree on amplifiers being plugged directly into wall outlets, each has their own, except for the BasX amp. |
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Post by leonski on Nov 27, 2023 1:07:23 GMT -5
My Panamax is the 5510-Pro........ While YOURS is the only one I see listed with voltage correction.....and I'd be curious as to current limits.... MINE is the only one with an ISOLATION Transformer.... Voltage correction is a neat idea, but HOW? The iso trans? Balanced or Isolated....on the ISO Trans has something to do with the grounding scheme. Mine has a front panel outlet AND a back panel XLR connector used for a light-on-a-stick....a flexible 'stalk' for point lighting. Front panel level control for indicator lights AND this lights intensity.... panamax.com/wp-content/uploads/m5510pro_datasheet.pdfI never noticed before, but the RS232 plug is for integration with some kind of home automatiom scheme. I never ever messed with that and have NO idea of the protocol or usage..... |
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KeithL
Administrator 
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Post by KeithL on Nov 27, 2023 9:41:31 GMT -5
OK.... Some of the older XPA-5 amps will make a little tweedling or beep-beep-booping noise when you shut them down. It has something to do with the impedance of the source device you have connected to them. So... it may happen on different channels... or with different inputs... and may or may not happen with a different source... or different cables. It won't hurt anything and doesn't specifically mean that anything is wrong.I recently upgraded my processor from an old Marantz AV7005 pre-pro to an Arcam AV41. On the Marantz, I was always using unbalanced cables to my Emotiva XPA-5, but when I upgraded I moved to XLR connections. Now, when I turn the system off, I am getting strange noises out of one of the surround channels, which I have been able to trace back to an amplifier channel closest to the power cord. To do this I swapped XLR inputs into the amp and then swapped speaker cables to make sure it wasn't noise picked up after the amp. Has anyone else experienced this? Additionally, I am getting a faint helicopter sound on my subwoofers which feels indicative of a ground loop issue in the system (which may or may not be unrelated). The chirping sounds occur even when the subs are disconnected, so I think I am fighting two separate issues here. Both subwoofers are the Emotiva XS15s and they worked flawlessly with unbalanced inputs, but moving those to balanced connections has created more issues. Any advice is appreciated. |
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KeithL
Administrator
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Post by KeithL on Nov 27, 2023 10:08:30 GMT -5
Voltage correction is sort of a neat idea... but most modern solid state gear doesn't especially care what the exact line voltage is. (It's mostly older tube gear that can get fussy about that.) The catch is that, in order to "adjust" the line voltage, you must choose between one of several methods, each of which has some serious drawbacks. In the very beginning this was done using transformers or transformer windings and relays or switches. Very early units would literally switch a small separate transformer in or out of series with the main power to boost or buck (cut) the voltage. So, for example, they would have a transformer with 2V and 5V windings, which could be used to add or subtract those voltages to the overall voltage. This sort of thing could be used to protect "appliances" from excessively low or high voltages, but literally jumped up and down, and so wasn't especially good for audio gear. (I don't think those have been made in years but you do still see them around from time to time.) Some more modern units actually regenerate the entire supply voltage - like a UPS when it's running on battery power. This means that they tend to be more expensive and complicated. And, as with a normal UPS, they may or may not produce a "clean sine wave"... so they may or may not generate an accurate but "noisy" line voltage... And they may also have issues with being able to deliver enough current to properly run a power amp. Without going into a lot of detail - an isolation transformer creates a separate circuit whose ground is isolated from the ground on the power grid. This then allows you to decide how to connect those two grounds together. (An isolation transformer is the only way to isolate your circuit ground from the ground on the power grid.) In general the link between something like a UPS or power conditioner is intended for two purposes. It allows the power monitor to "report" the current status; and it allows the system to control the power conditioner. One common use with a UPS is shutdown. The UPS "tells" the system when it switches to batteries... giving the system time to "order everything to do an orderly shutdown"... A modern system could tell your computer to do a backup, shut off the computer when it's done, turn on the emergency generator, and send you an e-mail about it all. RS-232 is still popular for many older systems and so is still used or offered by some modern gear. My Panamax is the 5510-Pro........ While YOURS is the only one I see listed with voltage correction.....and I'd be curious as to current limits.... MINE is the only one with an ISOLATION Transformer.... Voltage correction is a neat idea, but HOW? The iso trans? Balanced or Isolated....on the ISO Trans has something to do with the grounding scheme. Mine has a front panel outlet AND a back panel XLR connector used for a light-on-a-stick....a flexible 'stalk' for point lighting. Front panel level control for indicator lights AND this lights intensity.... panamax.com/wp-content/uploads/m5510pro_datasheet.pdfI never noticed before, but the RS232 plug is for integration with some kind of home automatiom scheme. I never ever messed with that and have NO idea of the protocol or usage..... |
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Post by leonski on Nov 27, 2023 16:21:35 GMT -5
When I was doing quartz crystal oscillators, the base frequency was adjusted using a GE X-Ray machine which DID have the transformer
system of voltage adjust. A VERY complicated machine, I was once sent up to the local Thrifty to test ALL the tubes. Basically a shopping
bag full.... System was used to bounce x-rays off a quartz crystal. Various properties could be 100% verified by use of this method.....
This was maybe 1975 thru 1980 range.
ISO is THE way to go for some applications. It also helps noise reduction on the 2ndary side. I think a basic power conditioner could be
made from say....a 1.5K VA transformer and a bunch of MOVs at the input side. You could power an entire system by this method.
Any system which processes the AC might Add noise to the output. Just the opposite of what you want. PSAudio does very well with
their system called 'Power Plant'.....they start at over 2300$ and go way UP.....And make great claims for cleanliness and accuracy of output.
And while we are talking all this 'correction'? Keith may want to chime in on PFC.....Power Factor Correction....
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