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Stir the pot - AC signal and AKSA processing

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This has been quiet, how about some academic work for the mind?

I decided to bring back an old problem to the table, i never got rid of it so i have been till trying to find the cause. I suspect my AC power is a piece of S***.

I have noticed with the Mayas that i have a very susceptible system, being the transparent speakers, the amp or whatever.

Some times during the day or night, i get a buzz from speakers that last 5-10 seconds. Sometimes this occurs 3 or 4 times in a row and then stop for a few hours (to happen again). So a small disturbance in the AC line i thought....from whatever cause....

ITs difficult to catalog the pitch sound, maybe some 200Hz to 500Hz.

I have had a PS AUdio PPP (power regenerator) for a while now, and i can confidently say that when the amps are connected to it, the buzz is much smaller. So it is kind of fixing 70% of whatever is coming in from the line. It is still there.
But with the amps connected directly to the wall..it is much louder.

So in enters a new kid on the block. A PS Audio P10. This is a monster of a regenerator. Its big, heavy and expensive. I bought this after much consideration, i got a good deal on one and went for it. I still did not plug my amps to it....but it comes with a new feature that led me to write THIS.

It has an embedded oscilloscope !What a cool feature. It cannot zoom in , or change scale, but nevertheless is quite nice. I plugged it in, to a wall socket next to the PPP. So both are connected but only the PPP is powering the amps.

Now....the other night the speakers started buzzing and i rush to the P10 to see the AC wave form and distortion values....i got to record 3 seconds of the distorted AC wave !!!! Here it is :

YouTube

The anomaly is the first 3 seconds. I recorded with my phone. After this i kept recording to see if it happened again, no "luck".

Now...WTF is that ??? What kind of harmonics are in the AC line to produce such a distorted ac wave ? Funny..if one counts the peaks, there seems to be from 10-12 each cycle....which would translate into 300HZ harmonics ? 6th order?
Is this the sound i am hearing ?

Ok, now academic for Hugh :

1. Why do the Mayas show the buzz on the speakers, and another commercial amp does not ? I used to own Marantz and Denon products and never "heard" the buzz. I can connect a Cyrus amp i have in the closet and be SURE of this. I would have to have both connected to identical speakers to make a 100% assumption.

Maybe the commercial amps have some kind of filtering ? I find that hard to believe as there is no better and complex filter than the PS AUdio itself and it still lets some noise pass.

Maybe the topology of the Maya is too transparent?

DO you think this noise is coming from outside my house, or something within ?
I contacted my electricity company, that says is going to install a "analyser" in my house for 8 days to measure and record data. Maybe this will show them the distorted wave and they something to offer here.

I have talked a lot....i will let you think now :)
All the best
Filipe
 
Have you considered the possibility that the interference enters your system in other ways too? Perhaps the disturbance is close to you and there is a strong radiation component as well which enters your system through an input. Is it possible to test with the amp inputs short-circuited?
 
Whatever happens inside the amp is downstream.
My problem is upstream, as noted at the input voltage wave in the PS AUDIO regenerator.
This P10 is only connected to the wall socket, nothing else. IT shows the AC sine wave completly distorted.

The fact that this noise is traveling through the AC input, to the amp circuit is another thing.
But the problem remains in the AC input.
 
We have problems with off-peak ripple control signals at 1050Hz but only effects ceiling fans in the early hours of the morning.

To make sure that's all it was I ended up unplugging everything and turned them on 1 by one to eliminate them as a noise source.

Doesn't help you but looking for external sources can help to find the culprit.
 
We have problems with off-peak ripple control signals at 1050Hz but only effects ceiling fans in the early hours of the morning.

To make sure that's all it was I ended up unplugging everything and turned them on 1 by one to eliminate them as a noise source.

Doesn't help you but looking for external sources can help to find the culprit.

Are you saying your ceiling fans were generating the noise in the AC line?
I am trying to find the culprit, but its kinda hard because i dont know when it will happen and when it does, its for 5-10 seconds.

Funny enough, last night i was testing a new amp build (old LifeForce brought back to life) and i all i had connected to it was my Smartphone.
So, no common ground on the rca input, just floating from smartphone.
I heard the PSAUDIO tripping into protection, and immediatly put my hear to the speaker and paused the music : NO NOISE

This got me thinking, is the AC noise getting in the line level input through some other equipment on my rack, or router , or tv, or whatever.....
 
Hugh,

You posted this answer on my other topic where i "presented" my new LifeForce chassis.
I will copy it here and continue the chat:

I think that there is a possibility that the Maya is indeed very sensitive to input signal, and it might show up as crackles and plops when other domestic appliances switch on an off. Try this: Put in a 3.3nF 100V filmcap across the output binding posts. It might alter inputs through the speaker leads, which are often an issue in sensitive amps.


I was able to check the "buzz noise" during the 5-10 seconds AC anomalies i get in my house. My MAYA was only connected to speakers and AC. No RCA cable was connected.
I heard the buzz just as loud as with the RCA cables....so this is AC caused 100% sure.

Furthermore, i have a new PS AUDIO P10, which is a top of the line regenerator.
Still....with this new P10....i hear the noise. So my AC has to be really really bad, in these short periods of time, for the P10 not be able to filter it out completly.
But..it is doing something because with the MAYA directly connected to the wall, i get A VERY LOUD BUZZ during these brief seconds.

So now we know what is causing this, how should i fix it ?
I already called my power company and they will install a 8 day analyser inside my house. But as i am not sure they will fix anything (only my audio system is complaining, and not everybody has this audio system) i will continue my search to fix it myself.

I am yet to test a commercial amp connected at the same time, just to check if it buzzes.
Still, i was thinking of putting a MOV across the mains?
 
Felipe,
I've been reading your posts on your AC issues. I seem to recall that you previously had AC noise issues related to a motor that powered some blinds in your house. Nothing about that here.
In reading your posts I've read that you have:
1. Intermittent AC line noise of unknown origin.
2. You have a PS Audio Power Plant Premier Regenerator.
3. You have a PS Audio Perfect Wave P10 Regenerator.
4. The regenerators reduce, but do not eliminate the noise.
5. You have a Maya.
6. The local power company is going to attach a monitor on your AC line for 8 days to help determine the cause/origin of your AC noise issue.

Okay, you are writing as if the Maya is the issue. They Maya merely amplifies the AC noise which you hear thru the speakers. The Maya is working fine and doing what it does, amplify. There is no AC filtering in the Maya.
It is commonly thought that amplifiers have some kind of AC filtering in their power supplies. But unless you know the particular unit and circuitry, you just don't know.

I would urge you to connect up your other amplifier and see how it goes with the noise.

Have you contacted PS Audio at all? Their engineers are pretty smart and perhaps could help you if you explain the issue to them clearly.

Have you thought about trying an isolation transformer connected to the wall power point and then to the amplifier or regenerator.

You have a difficult problem. As with all such issues you really have to find the source of the noise and eliminate it there, although that is easier said than done.
 
I hear you all, thank you for helping.

Hugh, i replied to you email. Thank you. Sourcing parts now.

Stvnharr, you are right about issues with motor blinds but i remove them from the main equation because they are not important. I keep on learning as i go testing. I am focusing on what seems to be the main issue.

So, to your kind considerations:

1. Intermittent AC line noise of unknown origin.
YES

2. You have a PS Audio Power Plant Premier Regenerator.
I sold them.

3. You have a PS Audio Perfect Wave P10 Regenerator.
YES

4. The regenerators reduce, but do not eliminate the noise.
YES

5. You have a Maya.
YES. I have 5.

6. The local power company is going to attach a monitor on your AC line for 8 days to help determine the cause/origin of your AC noise issue.
YES. Dont know when though.

I am not assuming the issue is the MAYA. I am saying i did not notice the buzzing with other commercial amps i owned. I already informed Hugh, that for sake of reason and FAIRNESS i will plug the LIFEFORCE and a CYRUS commercial amplifier to the same speakers to see on which i hear the BUZZ.

I will of course post my findings. This is the quest for truth , not rambling.

PS Audio is nice. It sure reduces the noise but does not eliminate. It is working fine, they all were (i had 2 PPP previously that behaved the same). PS Audio say that i should contact my power company. No news here.

I will do the amp comparison now. No point on changing more than 1 variable at a time.
Will come back with findings.
Thank you all
Filipe
 
Steve,

Thank you for the link. That was an interesting reading. Quite a "bash" on PSA regenerators. I guess that from a pure eletric engineer pov i agree with it though. But i can also say that it makes an audible difference. Why i cant say though.

Noise is a nasty litle bugger in my house. The power company just removed the analyser device today, it was on the past 7 days. I must say that i am either bewitched or i am being the target of a prank here. During these 7 days, i could not hear or detect any noise in my system. I had 3 amps (Maya , Lifeforce, Cyrus) connected to my speakers at the same time, to check on wich i heard the rattling noise. I can say that during the past 7 days, no noise was evident.

I bet the power company will say that no noise was detected and i am on my own now.

So i am torn here. I really do not like "not to understand" whats happening .
I will not touch anything the following week. The device is gone, we will see if that was in any way filtering the noise, or if removing and inserting the power switch on my main board made a difference. Time will tell.
If no noise is evident the coming week, i will start plugging and unplugging devices.

IDEA : what do you guys think about a "bad neutral connection" on the mains switch? Could this cause a distorted wave, while still maintaing a steady voltage?
 
Well Hugh, i must be honest and say that at the moment NONE show any signs of problems or noise.

In the past (until about a week ago) it was frequent but i can't nail it down to wich amps.
I must do carefull testing and wait for it to happen again. At the moment i have only the Mayas connected.
 
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