Schiit EITR

[One and a half]

@Charente, a BPS is very good at 'reducing' the noise created by audio components, mainly due to the cancellation techniques of the design. 

 

Effective treatment of incoming normal mode noise however a BPS struggles with. Quite a few of us have used an isolation transformer ahead of the BPS and it works in four ways. 

 

- Reduces common mode noise (hot and cold to ground) by 140dB

- Reduces normal mode noise 20-60db depending on the construction of the Transformer 

- Moderates the high current pulses from the primary of the BPS. What happens is the cancellation of the noise that a BPS provides has to go somewhere, and it ends up on the primary of the BPS transformer.  This noise creates current lumps and is not that friendly. To overcome this problem,  the isolation transformer smooths the current lumps. 

- Is very resistant to mains surges and effectively blocks them.

 

The best isolation transformers for this specific audio use are no longer made, but are still available on the used market.

Eaton manufacture a Power Suppress 100, but only for 60Hz systems.  The search is on for either Topaz, Elgar or xentec brands which work for 50Hz or 60Hz systems. The best isolation transformers have a very low capacitance value which blocks a higher frequencies noise. Typically these are stated at 0.0005pf or rarely 0.0001pf. Nothing much gets through that.  

 

Don't use any power distributors with suppression devices, they aggravate leaks - poison. Plain Jane types are just fine. The isolation transformer does the rest.

 

More details are in the Uptone section at CA, with now a 37 page topic dealing with isolation transformers. These items are not off the shelf products and need to be modified by professional electrical people. It's a bit of a challenge at times, but the sonic results speak for themselves. 

[One and a half]

13 hours ago, Charente said:

@One and a half Thank-you for your additional comments ... interesting and useful to know ! I suspect any modifications are beyond my pay-grade !  ... but I will enquire with Airlink as they are happy to consider custom solutions ... although I suspect it may not be cheap.  I'll also look at the isolation transformer thread you mention .. I might learn something.

Appreciated. Airlink are prepared to be responsive, maybe with enough interest, an isolation transformer for audiophiles may be offered as a standard product line.

These days everyone uses a UPS, but they are so AC unfriendly, create noise a lot worse than any PC, and their output is not much better than the wall but are cheaper and lighter than an auto transformer, but not as quiet!

[One and a half]

1 hour ago, Charente said:

I couldn't resist posting this ... a new (to me) network player/server, with a full array of outputs, Roon support, major streaming services and internet radio services ...

 

 

and a matching DAC ...

 

 

https://www.nativsound.com/en/music-server

 

It's beautiful..the timber, not often seen with metallic electronics.. the price is surprisingly very tempting. The outboard power supply is a necessity, at least it is away from the processors in the screen. Man it must have some good shielding. The spaghetti should be out of sight (mostly). Very nice indeed.

[One and a half]

The Niagara certainly looks a lot better than the Topaz, has all the outlets built in. From a convenience point, the Niagara would take the prize, the Topaz being the ugly duckling. The Topaz would need to be fitted with a distributor, earth fault protection and if you can hide it, the 1000 has no common mode noise reduction at all. The efficiency stakes, the Topaz wins hands down, and is still cheaper than Niagara at 50% off.

Forget all the current delivery nonsense of the Niagara, just size a Topaz accordingly and it more than enough provide current for any amp.

[One and a half]

53 minutes ago, Charente said:

In my setup I have a Balanced Power Supply ... when I did some swap-out tests some months ago, I found the SMPS's (and the MacMini) affected the SQ, so I kept them outside the BPS and plugged the DAC & AMP into a strip off the BPS. I also tested the EITR transformer on both sides of the BPS and found it to be better away from the SMPS's as well , so CURRENTLY it is sharing the same strip as the DAC & AMP. It does sound very good in this arrangement, but I think ideally it should be separated and the only way I can achieve this with my electricity supply wiring in the room is to get another (small) BPS just for the EITR transformer to isolate it from everything else. This perhaps sounds OTT, but I think worth a try and I'll report back on whether it makes any difference. My experience with the BPS resulted in worthwhile gains and if nothing else, it can't do any harm, I would think.

Unless wholesale mods are performed on the Mac mini and other high leakage impedance noise sources, it is an optimum solution to leave them alone and isolate their effects somehow. 

 

Adding a second BPS was thought to be a bad idea since the 2nd BPS due to inherent differences in output voltages would cause more problems with the signals downstream.

 

One way around the problem of two BPS is to connect the centre points of each transformer to earth/ground. The point here is that it keeps the reference at the same potential between the two systems and any assymetric voltages are dealt with by the respective transformer noise cancellation.

A GFCI is still required for the 2nd BPS and the connections that run with that. 

How to join the two earth grounds is to open the connection covers and find a secured exit for a 4 or 6mm single green yellow wire and connect the two transformer centre points. This is simple inside a panel but using cables and connectors is doable but needs some DIY skills.

[One and a half]

6 hours ago, Charente said:

 

Ah, OK...thank-you for the words of caution and the fix suggestion ... although I fear any mods to the BPS are well beyond my competence levels . Might be useful for other members tho'. 

 

 

That can be a measurement project for this year ?

[One and a half]

9 minutes ago, buonassi said:

scratch the above.  Happened again.  NOT SOLVED. 

 

I'm not sure what it was that caused it to work the one time just fine.  AC switched off and no detriment one time out of 5.  The remaining 4 times, I'm back to the same dropouts when the AC kicks off.  

A Topaz/Elgar/Xentec transformer will fix that. Otherwise, replace the switch/thermosatat in the air handling system for a new one. The contacts are probably worn, and when the voltage is interrupted, there's a burst of conducted RF with enough strength to show up on the Eitr. Well it goes to prove, there's only a transformer in the Eitr power supply.

[One and a half]

1 minute ago, buonassi said:

will any "isolation transformer" do?  Or are these known to be true isolation transformers vs floating transformers?  I'm thinking that even an A/C line filter may do the trick, but may as well invest in a good isolation transformer for my entire rack of gear if this is advisable for other gear as well.  

The Topaz and the like are passive surge suppressors and common mode noise killers that’s the main reason for the recommendation. The Topaz for example reduces a 6000V transient to mV.

[One and a half]

1 hour ago, buonassi said:

 

Well, I had a hard time sourcing the brand names you mentioned, but I found this readily available (and returnable if it doesn't work out).  Looks like it ticks all the boxes so I ordered it and it'll be here Monday, we shall see:

 

https://www.amazon.com/Tripp-Lite-Isolation-Transformer-Outlet/dp/B00006HPFH/ref=sr_1_5?ie=UTF8&qid=1528567477&sr=8-5&keywords=tripp+lite+isolator

Should stop the noise, it will be a good test.