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-   -   Stir the pot - AC signal and AKSA processing (https://www.diyaudio.com/forums/aksa/327764-stir-pot-ac-signal-aksa-processing.html)

saf 1st October 2018 09:26 PM

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?

Max Headroom 1st October 2018 10:21 PM

Check your earth connection all the way to the ground stake and check A-N voltage differential.



Dan.

AKSA 1st October 2018 11:47 PM

Filipe,

I think we need to improve the phase margin on the Maya - easily done - to suppress Mains hash. I think this could be the issue.

I will email you with the detail and explanation.

Thanks for the email, and to Dan too.

Hugh

stvnharr 2nd October 2018 03:53 AM

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.

saf 2nd October 2018 09:25 AM

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

stvnharr 9th October 2018 02:28 AM

Felipe,
Have you seen or read the following thread?

Amplifier as Power generator example PS audio power plant

If you go to Post #17 and read the Rod Elliot article it gives some good information and insight on the troubles you've written about. It's a good read if nothing else.

Steve

saf 11th October 2018 02:20 PM

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?

AKSA 11th October 2018 10:17 PM

Filipe,
I believe it would, but the safety relay in the house switchboard would trip if there would be a bad connection from neutral to ground (assuming single phase of course).

Do you notice this with the Lifeforce and the Cyrus, Filipe?

Ciao,

Hugh

saf 12th October 2018 09:32 AM

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.

AKSA 12th October 2018 11:29 AM

We live in hope, Filipe!!

Good luck to all of us, and our creations........

Hugh


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