Transformer Hum (again)

A custom Airlink - wow, did you feel that the Airlink  improved the sound quality with the 500 series gear as well as elimination of the hum?

Thanks,

Mario.

"Got myself a AH! DC Offset Killer. No hum/buzz since. I'm sure other offset killers will do the trick too, it's not an overly complicated design."

I tried an AH! DC Offset killer too, last year, as my (then) Nait 5si hummed like crazy. It sure killed the hum/buzz from the moment it was plugged in, but it also completely ruined the Naim sound. (softening the treble and dynamics, making the sound very dull/boring)

Alco posted:

"Got myself a AH! DC Offset Killer. No hum/buzz since. I'm sure other offset killers will do the trick too, it's not an overly complicated design."

I tried an AH! DC Offset killer too, last year, as my (then) Nait 5si hummed like crazy. It sure killed the hum/buzz from the moment it was plugged in, but it also completely ruined the Naim sound. (softening the treble and dynamics, making the sound very dull/boring)

Alco

do you have any experience (direct or indirect) with Kemp Elektroniks DC X-Terminator when used with Naim amps/PSU's?

LarsDK posted:

I am using a syncro with great results to remove DC-led buzz. As you can see in my profile, this plugs into a good passive powerbar, which I can recommend.

what I dont understand is that you write that syncro into 250.2 has no results. Do you mean that it does not stop the buzz/humm, or that the amp does not get enough power?

i will myself try to take the syncro out to see if that opens up in case its the second one you mean

lars

The transformer has a mild hum with the Syncro plugged into the Sirius, which works really well, However the Sirius does not provide enough current for the 250DR, hence the desire for an alternative which allows for the "second" socket on the wall outlet. I have a dedicated spur to my room. I could get another Syncro to solve the problem, or look at alternatives for less than two grand, which is the better option. Chhers

DaveBk posted:

... I use the 250v primary to effectively step down my input voltage to a tad under 230v and eliminate the DC offset through the grounded centre tap on the secondary.

Interesting Dave.  This is a very similar path to the one that I have taken.  In my case, it's a 5kVA version with grounded centre tap on the secondary.  It has a choice of 5 different output voltages, in approximately 10-12V steps.  This afforded the choice of either 232V or 242V output at the living room wall socket.  After consultation with Naim about which to go with, the recommendation was 232V on the basis that "you won’t lose a noticeable amount of headroom and everything gets a much easier time of it."

That final 10V drop also eliminated the last hint of hum from the 555PS transformer, so that is how it has been set to this day.

Best regards, FT

"Alco

do you have any experience (direct or indirect) with Kemp Elektroniks DC X-Terminator when used with Naim amps/PSU's ?"

Sorry Aleg, I don't have any experience with the Kemp Elektroniks DC X-terminator. I only tried one from Supra first and then the AH!
Both did the job by stopping the transformer hum directly, but both also had a bad influence on the sound. Therefore I gave up, trying other dc-offset blockers.   The result is, that I'm kinda forced to stick to Unitiqute level, as anything from Nait 5si level and higher will (most likely) bring back the humming issues.

Alco posted:

"Alco

do you have any experience (direct or indirect) with Kemp Elektroniks DC X-Terminator when used with Naim amps/PSU's ?"

Sorry Aleg, I don't have any experience with the Kemp Elektroniks DC X-terminator. I only tried one from Supra first and then the AH!
Both did the job by stopping the transformer hum directly, but both also had a bad influence on the sound. Therefore I gave up, trying other dc-offset blockers.   The result is, that I'm kinda forced to stick to Unitiqute level, as anything from Nait 5si level and higher will (most likely) bring back the humming issues.

Thanks for the reply. You being Dutch as well, I hoped you might have encountered Kemp Elektronics. I don't know how large an international following Kemp has, to find it in combination with Naim gear.

After speaking with a few people who have tried these and have heard no change in sound, I have ordered the Emotiva CMX-2. Probably the cheapest DC blocker on the market at $99. They are not current limiting as well. At that price, if it does effect the sound, no real loss! Will post results when I have them. 

Well, the CMX-2 is now in place, and so far, has killed the hum, even from the Kettle .... Also, it has brought back much of the naim sound that I was missing since installing a UPS a few weeks back. It makes me nervous running without surge protection, but at the cost of losing naim sound, what can you do? I will keep looking for bigger and better power systems, as long as they don't affect the SQ.

I use a combination where the Syncro feeds the IsoTek Sigmas directly from a dedicated main outlet - solved all my problems in a system with 1 x 250, 2 x 200 and a Hi-Cap DR

Stenberg posted:

I use a combination where the Syncro feeds the IsoTek Sigmas directly from a dedicated main outlet - solved all my problems in a system with 1 x 250, 2 x 200 and a Hi-Cap DR

 

All the reviews just talk about its conditioning abilities. Does it have surge protection as well?