XXHighEnd

I didn't know where to put this so thought I'd start a new topic...


With a bit of encouragement from Peter, I decided to bypass my 15KVA isolation transformer and replace my dedicated earth with the house earth. I've been very reluctant to do this because the 15KVA isolation transformer & dedicated earth took so much time and money to set up. It was hard to even contemplate this was all for nothing.

(Just to be clear, I'm still using a dedicated AC mains ring. There is a seriously heavy-weight cable running directly from my house AC meter to a dedicated consumer unit for the hifi. Everything has been designed to offer the lowest impedance possible for the hifi components. The PC still runs off a 5KVA balanced transformer.)

The sound has totally changed. The Orelos now sound ‘alive’. They now sparkle. But the smoothness to the sound remains. At first, I didn't think the bass had become extended, but I know think it has. But it is certainly much more tuneful now. The whole sound is tighter, allowing the rhythm of the music to be more easily followed.

Overall, I now have the most realistic sound I’ve ever heard in my room. I’d go as far as to say that I'm now almost on par with Paul’s (Scoobius’s) sound. The main difference is that I don't get the subterranean LF that Paul gets, due probably to his room dimensions. But even this may be 'fixed' when we undertake some major building work on the house, including extending the room, as we hope to do in 18 months time or so. But for now I'm over the moon.

Just wanted to share. Oh, and if you're using any mains products (filters, transformers, regenerators, etc), you should try by-passing them to see what they're really doing to the sound. I'm now convinced that all you need is the lowest impedance power source possible, and most of these devices simply do not allow this.

Mani.

Good that your SQ changed for the better  :)

These mains products can be puzzling. I had bad results with PS Audio Powerplant Premier. Currently my computer and NOS1 (not yet a) are on a Purepower 1050 and my poweramps are on a seperate dedicated ring (6mm2 mains cable).

Recently I bypassed the Purepower and the SQ detoriated significantly. I'm curious if the NOS1a will be less sensitive for the Purepower.

To be clear for the readers, the Purepower is not a transformer or filter, but regenerates a clean 230V power.

Stanley

Hi Stanley, I have a PurePower 2000 here and I agree that it certainly changes the sound. There are two big problems I have with it:

1. There is a big difference between how it sounds on battery vs. regeneration modes. This rings alarm bells for me. The battery sounds smooth, but 'flat' (a little like my isolation transformer). The regenerator sounds much brighter and has more sparkle, but the LF just disappears and the sound is a bit 'edgy'.

2. My 'noise sniffer' goes ballistic with the PP2000 hooked up. The PP2000 has a large switch-mode power supply, which is obviously very noisy electrically. What's interesting though is that the noise sniffer goes ballistic when connected the output of the PP2000 (even with zero load), in both battery and regenerator modes. The PP2000 may well provide a nice, steady 230V, but I'm not sure how 'clean' it actually is.

You may be aware that these older models seemed to have a lot of quality issues with apparently lots of variations between units of the same model. Mine has worked perfectly since I bought it 4-5 years ago, but may well be one of the 'not-so-good' ones sonically, and perhaps yours is? Dunno. But certainly mine has been gathering dust for the last couple of years and I certainly wouldn't use it now with the sound I'm getting with a 'direct' AC feed.

Mani.

Hi Mani,


Do I remember correctly that the noise sniffer did confirm the (PSU switching) noise isolating properties of the 5KVA transformer or was it the big one?

thanks,

regards, Coen

Hi Mani,

in the end .......... suceeded.

I see that you are willing to spend "some" money for a good SQ.

In Germany the company
http://www.hmselektronik.de/index.htm
has some good ideas.
The SOTA is a unit  "Energia Definitiva High End Power Supply" for appr. € 7500,00, but I can't find any reference in English, except:

http://www.hifi-phono-house.com/product_info.php?language=en&products_id=8953&XTCsid=820b71982a252ad909edba1ecae474ca

They have some smaller units (RC 4/3) with a similar concept starting with < € 2700,00 too.

Joachim

Hi Mani - so my understanding from what you say is that your amplifiers (in the MkII's) and your NOS are powered from a consumer unit on a dedicated spur (i.e. not a ring) and that the earth (for PC and NOS) is connected back to the point where the earth comes into the house (is that correct?).

So the PC is powered from the 15KVA balanced transformer. Is the supply to the 15KVA transformer from the dedicated hi fi spur? and if so how is the earth connected on the output of the 15KVA balanced transformer? because obviously that cannot be connected to the earth of the amp/nos (or there would be a loud pop!!). Unless the earth of the USB cable (between nos and PC) is not connected at one (or both) end.

Glad to hear that you are getting sound you are happy with.

I have been meaning to bypass my 15KVA balanced transformer but I have just been too busy listening to music. Which, as excuses go, is a pretty good one!!

Anyway it has just moved up my list of job priorities.

Cheers

Paul

About noise sniffing ...

For something like a Pure Power unit it should be okay, but do notice that re-generated power "normally" outputs a square-like wave (springing from pulse code modulation). For example, all UPS'es are (Uninterruptable Power Supplies for computer stuff). So you always need to confirm it outputs a nice sine.

Peter

I have my PC in a Monster filtered power block. This is a no brainer compared to having it plugged in directly in the strip, but may have some drawbacks that I am not aware of yet.

Next to the unexecuted plans to revert to a linear base supply I also contemplate about the virtues of the isolation transformer. It seems a much more simple solution to eliminate the coupling of switching noise between PC and amplifier.

I noticed that the isolation transformers used are very over -dimensioned. Why would one choose a 5KVA transformer for a 50-100Watt PC load? I think big ones make sense for audio amplifiers but for a PC....?

Is there anything to share about isolation x-formers for a PC application?

Thanks,

regards, Coen

Hi Joachim, thanks for the reference and link. But quite honestly, I'm done with playing around with the AC mains... for now at least.

Mani.

Hi Paul...


Yep, and yep.


The output earth of the 5KVA balanced transformer (and not my 15KVA isolation transformer) is simply connected directly to the input earth (from the dedicated spur), which itself is connected to the house earth.


Not sure what you mean here. My understanding is that the amp gets it's ground (and not protective earth) from the NOS1a, and the NOS1a gets it's ground (and not PE) from the PC via the USB cable. In any event, there are certainly NO bangs or pops here!

Mani.

Hi Coen, in my case it's simple - it's what I already had. When I bought my 15KVA isolation transformer my two 5KVA balanced transformers, I specifically went over-the-top because the idea was to run the whole system from the transformers, and I wanted to keep the impedance as low as possible. But for the purpose of just feeding the PC, I totally agree that the isolation/balanced transformer needn't be very big.

Mani.