Jay's Audio CDT2 MK3 hum

I’m not familiar with your country’s electrical distribution system. But if your nominal voltage is 230 and you’re measuring 260V, that’s about a 13 percent deviation. That’s a huge discrepancy. In the US, for example, power is generally regulated to within 5 percent. So if it is at all possible for you, I’d suggest exploring whether your utility can improve its voltage regulation. Sometimes, a utility doesn’t know it has a problem until someone alerts them.

Sorry my comment is not helpful to Tomasz, but I'm interested that you mentioned PV and old power lines as the cause of the high voltage.  I recently installed solar PV, and occasionally one or two of the panels stop producing power because of high voltage.  My solar company reported: "Based on our checking, the system encounters high voltages ranging from 250-262V from time to time."   So perhaps this will become more of a problem with more solar installation in the future?

Tomasz - is the problem only during the daytime, or do you also get the hum at night? 

Bummer. Can't help you since I run USA power, no clue what EU power units may sound like. My Jay's cdt2-mk3 has been nothing but pure joy. If I understand you correctly, on your next purchase, make sure you buy directly from Beatechnik. They specifically say that any of their equipment bought from the various Chinese outfits that discount their items is not covered by their warranty. Obviously the $300 savings is insignificant now. 

@cleeds : Here in Poland +/- 10% is allowed, so up to 253V is "OK". Technicians were called, checked the voltage and confirmed the problem is with excessive local production by PV installations. Power lines will need to be replaced which will not happen any time soon. In case of any damages excessive voltage can make, they pay for repair. I'm monitoring my installation with Supla system and Zamel monitors and all the anomalies are recorded.

@tonnesen My installation consists of two strings, 6 + 4 kWp, oriented east-west. Fronius inverter I have, stops working in case of 254V+ measured in any phase constantly for a few minutes, then checks back and if voltage dropped, starts again. The inverter stops working and not individual panels or strings of panels. Your installation must be different. Sure there will be more problems if more installations will be connected, here and where you live, if no new lines and perhaps auto transformers will be installed in the local network. 

No hum at night when voltage drops to 230V or below.

@baylinor I have a written warranty from a local-private importer so it is not that I am not covered. Starting this discussion I just wanted to be better prepared with my claim. If I get any responses from the members (especially from EU) that the transport is DEAD quiet (in the casing) at any excessive voltages, it will be strong indication that my unit needs repair. Another possibility is that all units slightly hum but their users are not bothered... Funny is that the Berkeley Audio Design HDCD DAC of the importer hums like hell (by my standards at least), but he likes it so much so ignores the noise. "Unfortunately" at his place voltage is dead stable so my problem could not be replicated. 

You said "no clue what EU power units may sound like" but I don't hear the power unit which is on the left side but something buzzing at the right side. Is there anything that could vibrate there resulting in 300Hz noise?

The ocxo board is located on the right side of unit. The only way to find out for yourself if something is loose causing a buzz is opening the unit and checking it out. Just be careful, specially with 220 power.

@tomasz1964 

if you unscrew the top, you will be able to watch the inside and power it to check where the buzz originates. Again use CAUTI0N! 

Sell it get a Hegel Viking. The bit perfect DAC built into that is probably better than your DAC now so you can sell that too!

Buying from overseas is very risky. Is Jay a dealer? Is he willing to take it back if you don’t like it.? How much did you pay? Sounds like a transformer problem, what does Jay say

Depending on the price you paid, you still might have got a better deal If Beatechnic’s warranty is anything like Denifrips. I bought a Denifrips DAC that started acting wonky.  After seven weeks of back and forth, I sent it in and they popped in a new DSP board and sent it back.  I paid shipping both ways.

All the best.

How about adding a power conditioner/regenerator?

My Jays CDT2 MK3 is dead silent but I"m in the US AND I power it via a PS Audio Stellar PowerPlant3. I'm not a big believer in "power cords" but I had an extra super thick power cord that came with some other product a while ago that was not being used - So, I have that in play also.

None of this may help or apply to your situation - but just wanted to add some options.

PS. I wasn't a believer in power conditioners/regenerators either... until I decided to "test" the PowerPlant3. But to my great surprise it made a noticeable improvement to everything.

Tomasz, my Jay's is totally silent, I would think that such a high voltage might cause the hum.

@pennfootball71 

"Sell it get a Hegel Viking. The bit perfect DAC built into that is probably better than your DAC now so you can sell that too!"

How do you know what DAC OP has. What an asinine post🙄

Thanks all for the comments.

@knock1 Thanks for confirming yours Jay's is totally silent. Are you from Europe? Have you measured your voltage? 

"I would think that such a high voltage might cause the hum": If this is normal situation with CDT2 MK3 EU version, it is quite disappointing. None of my other old and new EU made pieces seem sensitive to the voltage anomalies. ZERO hum even at 260V. The simplest test to see whether it is some design flaw or a problem specific to my unit, would be to borrow another Jay's and compare them side by side at my place. Not impossible.

@creativepart Thanks for confirming your Jay's is silent. I have my $80 power "regenerator" keeping my voltage at 228-232 V and it fixes the problem. Not the most elegant way, though.

@baylinor I don't want to break the seal on it to eventually lost warranty. Whatever it is worth... Would like to leave it to my importer but the problem is his voltage is stable and nothing buzzes at his place.

@tomasz1964 

I am in the US and never seen my voltage exceeding 122V, but it seems that you have solved the problem with regenerator, congratulation. Now, stop worrying🙂

BTW, my name is Tomasz as well.

@knock1 Hi Tomasz! So you must have Polish roots :)

Been traveling a bit but finally got the transport to the seller. He's borrowed an autotransformer to play with higher voltages than nominal and confirmed my observations. He's found that once the top lid is off there is no hum audible. He experimented a bit with the transformers, which don't produce any audible sound when the lid is off. With the lid on the screws needed loosening to silence the hum. So, the whole thing that bothered me whole summer is the transport housing resonance amplifying otherwise inaudible vibrations of the transformers. Hell knows why it is the strongest on the right side. I am relieved that it is only a mechanical "issue" and nothing wrong in the electronics. Although I fixed it by using a cheap voltage stabilizer, I might try to put some  anti-vibration insulators under the trafos, So there would be no rigid connection between the transformers and the transport housing. 

Again, thanks for all the comments.

@tomasz1964 

You bet!