Discussion of AC mains isolation transformers

[lmitche]

Good to know Mourip, thanks.

Looks like these old Topaz units need a good examination when purchased on eBay.

 

 

Sent from my iPhone using Tapatalk

My Isolation transformers hum is reduced as ground loops are eliminated. The last possible source of a ground loop will be eliminated next week. Nevertheless with the progress made so far, any hum is now inaudible.

[lmitche]

Hi mourip,

 

I have tried to get every AC and signal path isolated using AC isolation transformers with floating secondaries, Ethernet isolation transformers and one LPS1 with a second one on the way. Next week the Adnaco USB isolation gear arrives which will be powered by an lps1.

 

Having things linked in series is fine as there is only one path, if any, to ground.

 

The Adnaco is exciting as my HQplayer upsampling PC will now be completely galvanically isolated on all sides with the addition of the Adnaco device.

 

In the past, I tried the Intona device to achieve the same level of isolation. While my initial impressions were very favorable, over time I felt like the Intona had a sound of its own, so I sold it.

 

I am hoping the Adnaco device does better. If not I'll keep searching.

[lmitche]

John, I find a benefit to using small isolation transformers with a floating secondary for single digital components plugged into the shared power strip. My belief is these IT stop the type of grounds loops to which you refer.

 

So for instance, if I have a PC with its AC power from a single IT with a floating secondary, its ethernet connection isolated with a transformer, and it's USB isolated with an Intona or Adnaco Fiber/USB/LPS1 combo, isn't that the best of circumstances?

[lmitche]

Fuses? We don't need no stinkin' fuses!

 

But for those who do:

[ATTACH=CONFIG]31476[/ATTACH]

What's that 130 amp thing?

[lmitche]

Not that long ago!

 

http://www.slate.com/articles/life/design/2012/09/can_tabs_how_aluminum_pop_tabs_were_redesigned_to_make_drinking_soda_safer_and_the_world_a_cleaner_place_.html

[lmitche]

John, I've never seen a soldered connection under wire nuts. It seems like a good idea for stranded wire. Do you know why it's not a common practice?

[lmitche]

Lol!!!?

[lmitche]

Here's my brand! http://www.kinginnovation.com/pics/db/products/22/Red-Yellow-Gorilla-Nuts®-621.jpg

[lmitche]

Hi:

 

Topaz was known to build and sell their ultra-isolation (ultra-low interwinding capacitance) transformers to a number of companies for private labeling and resale into different markets. Indeed, both the castings and some of the legends on the labels are always the giveaway that it is really a Topaz unit (though it is always hard to say which level of ultra-low interwinding capacitance it is).

 

ECA (Electronics Corporation of America) was an old line industrial, medical, and vacuum tube company based in Cambridge, Massachusetts. I've seen their Topaz-made units with labels saying medical/dental, so I guess that was their market for them.

 

So yes, I would say they are worthy of consideration.

 

Best,

 

--Alex C.

How the hell do you know this stuff?[emoji1]

[lmitche]

Researching receptacle choices will drive you nuts. Here is what I did. https://www.amazon.com/gp/product/B008KNQAYY/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

 

There are PSaudio and other Hubbell choices lower on the same page. These all seem like common sense choices to me. The gripping power on the Hubbell's is formidable.

 

Do these sound better? It depends on what they replace. These are high quality brass receptacles from what is probably the best US company in the business​. While not cheap, they seem reasonably priced to me. SQ is great here, so the receptacle is certainly no bottleneck.

[lmitche]

Alex,

 

Here you go! http://www.ebay.com/p/Hubbell-IG5362-Duplex-Receptacle-Isolated-Ground-20-Amp-125v-NEMA-5-20r/1203988309

[lmitche]

5 hours ago, austinpop said:

 

Sorry, I forgot to mention a couple of isolators I already have in my path (in italics):

Data:          DC blocker --> Modem---> wired router------>W10 Roon Core--Baaske isolator----->modded switch--------->sMS-200--------->tX-USBultra------->DAC

 

Neither of them made any SQ difference for me.

 

 

I wish we got Qobuz in the US!

Try moving the Baaske between the router and W10 Room Core machine.  If that makes a positive difference, get a second one and install it in series next to the first.

[lmitche]

4 hours ago, austinpop said:

 

Hi Larry,

 

I've tried the Baaske in several positions:

- between modem and router

- between NAS and router

- just before the W10 box, and

- between W10 and switch.

 

None made an audible effect at all.

How strange!  Maybe you have a bad one.  Both here, and at a friend's, two EMOsystems ITs or Baaskes in series make a huge difference in both Win10 PC's and uRendu setups.

[lmitche]

6 hours ago, Daudio said:

 

Still waiting for someone more knowledgeable to come along. Till then could you refrain from muddying the waters with your idle speculation ?  TIA

 

Wow, great way to make friends and influence people. I'm impressed!

 

While we are waiting, maybe you can tell us what this quote from John Swenson means:

 

 "I plug EVERYTHING into the power strip."

[lmitche]

2 minutes ago, joelha said:

You're right to reference that quote, Imitche.

 

My only question is whether having amps on a completely separate circuit provides an exception to that statement.

 

Joel

Nope, everything means everything.  

[lmitche]

Joel, well both really.  I reached the same conclusion experimentally here, read John's post confirming the superiority of the design, and then followed the success of the same on Jud's system, and been reading about the success of many others on CA.

 

The logic is to limit the impedance between devices.  As devices, including amps,  are all connected at both the AC and interconnect level, having an amp on a second isolation transformer almost guarantees an impedance mis-match.

[lmitche]

7 minutes ago, Daudio said:

 

You follow that characters posts for a while, and come back and tell me if you think I was off base !

 

 

 

It means the optimal configuration. But when the 'optimal' meets the real world, things get more difficult. And, as an engineer, John understands this.

 

'Real world' in this case is a pair of amps in the basement. You got a better idea ?

 

Well, I guess you have to go with a sub-optimal solution, or use galvanic isolation further up the chain to create two separate isolation zones. (I have 3 GI zones). Is your DAC and preamp in the basement as well?

[lmitche]

9 minutes ago, joelha said:

Only my amps are in the basement, on shelves attached to the ceiling, to give them the shortest speaker cable run to the speakers immediately above them.

 

That configuration also allows me to keep the speaker cables and XLR cables to the amps out of sight

 

So the entire front end is on the main level. Only the amps are in the basement. My concern with plugging the amps into the main level isolation unit (if I were to get a unit with enough capacity to handle them) would be the very long runs of power cables necessary to connect them to that isolation unit.

 

Joel

Joel, do you have a DAC and preamp or are you using your DAC as a preamp?  Is it an USB connected DAC?

[lmitche]

16 minutes ago, joelha said:

I do have a DAC and pre-amp and the DAC is connected by AES cable from a Rednet D16 interface.

 

It is not a USB DAC.

 

Thanks to you guys, by the way, for trying to be so helpful.

 

I do appreciate it.

 

Joel

Ok, so you almost have two GI zones, one before the rednet, and one after, which are created by the Ethernet transformers in the NICs.  You may want to consider two separate AC isolation transformers, one for each.  I'd try plugging the amps into the second AC transformer along with the rednet and preamps.  Otherwise leave the amps where they are. Experimentally determine which sounds best.  This will keep the high frequency digital crap away from the analog side of the system.

[lmitche]

Many thanks Joel, always happy to help.

[lmitche]

34 minutes ago, Cornan said:

 

I have actually tried various JSGT in my system. Some of them makes the SQ much worse. My understanding while experimenting is that the network switch noises that actually travels via the JSGT ground wires into the other devices via the starpoint connection of the JSGT AC mains plug. Remember that my power distributor is positioned after the IT. My guess is if I connect the plug to the same AC mains wall inlet as my IT the noise will be forced to go through the balanced & floating IT back to the Gophert/Aqvox instead of being speaded around inside the floating walls of my setup. Right now my best option is for sure to connect the JSGT from Gophert to Aqvox switch to the Entreq Minimus grounding box, but I will try to ground it to the AC main wall inlet as soon as I have moved to my new place in February.

No question, some ground shunts giveth and some taketh away!

[lmitche]

15 minutes ago, SoundSparks said:

 

Why is the new unit better? Is it because of the lower capacitance (2 times lower) or is it due to the higher power (2.5 times higher)? What is the major contributing factor here?

 

Should the distance from the gear to the iso trans be taken into consideration? 2' vs. 10', e.g.?

 

Is 1000VA iso trans powerful enough for 600VA (total) of connected gear? I.e. is (Total VA)/0.6 = (iso trans power rating) an accurate enough approximation?

 

 

Goertz does not publish any detailed specs, unfortunately...

 

Please chime in!

A couple years ago I visited the Bridgeport magnetics factory, met the owner and found a stash of 7 Alphacore balanced power transformers in audiophile cases.  I sold 6 here on CA and kept one for myself.  Everyone seems to be pleased with their purchase. I know I wouldn't part with mine.

 

While at the factory I was told about the new transformers referenced above. They are likely to sound the same.  Plug a tripplite power strip into the transformer outlet and you are good to go.

[lmitche]

1 hour ago, SoundSparks said:

 

Thank you very kindly for the info @lmitche!

 

Hopefully, 1000VA, the largest Balanced Power Supply offered, will provide adequate power for my gear...

Could you please suggest me a suitable power strip from Tripp Lite? There are way too many choices and am not sure what product would be the best: Bench and Cabinet Power Strips, Hospital and Medical Power Strips, ...

 

Here is one, they have other models as well.  Avoid surge protectors.

 

https://www.amazon.com/Tripp-Lite-Outlet-Cabinet-PS361206/dp/B00VESUMSM/ref=pd_sim_23_4?_encoding=UTF8&pd_rd_i=B00VESUMSM&pd_rd_r=3P7HRMGPWYNJ8W54HCAW&pd_rd_w=pULWA&pd_rd_wg=E2wZ9&psc=1&refRID=3P7HRMGPWYNJ8W54HCAW

[lmitche]

9 hours ago, Jud said:

First, thanks to many people in this thread - John Swenson, Superdad, and especially Speedskater - for assistance and encouragement that allowed me to have a Topaz transformer serving my audio system circuit in my new home.

 

I wanted to post because I thought this tidbit might be interesting: Because the usual electrical inspector for the area had his son's wedding to attend, the chief inspector for the state came out to inspect the electrical installation, including the transformer. While done to the specifications in the (invaluable) Middle Atlantic paper, the installation was sufficiently unfamiliar to the inspector that he required it to be changed so the transformer draws its power from a wall plug rather than the original hard-wired arrangement.

Wow, what a bummer! Funny, people just always need to find a way to add value, even when they can't.

[lmitche]

1 hour ago, Cornan said:

 

Albtr´s balanced IT alumnus! I am fine with that!  

Nope, we know you are out of balance, and we like that about you!