Topaz Low-Capacitance Isolation Transformers - for Affordably Clean Power
post-13684520
Post #31 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
Last edited:
     Share This Post       
post-13685636
Post #32 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
     Share This Post       
post-13692410
Post #34 of 532

knowhatimean

500+ Head-Fier
Joined
Jun 16, 2011
Messages
839
Reaction score
134
Joined
Jun 16, 2011
Posts
839
Likes
134
So.. Mike, are you still using those empty wooden thread spools between your equipment ?

I'll bet you've even found a way to incorporate using them under these isolation transformers now ! (Sorry.... I haven't messed with anyone for a long time , It was time...He,he)!

On a serious note, I started using an Equi=Tech BPT years ago & I'm pretty sure that I'd be hard pressed to ever be able to enjoy listening to my music w/o it's benefits in front of my playback. The only drawback to it (& I do mean only) was it's price... Great thread !
 
     Share This Post       
post-13693723
Post #35 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
So.. Mike, are you still using those empty wooden thread spools between your equipment ?

I'll bet you've even found a way to incorporate using them under these isolation transformers now ! (Sorry.... I haven't messed with anyone for a long time , It was time...He,he)!

On a serious note, I started using an Equi=Tech BPT years ago & I'm pretty sure that I'd be hard pressed to ever be able to enjoy listening to my music w/o it's benefits in front of my playback. The only drawback to it (& I do mean only) was it's price... Great thread !
Hey!

Yes, I still use the wooden spools to separate my Metrum Acoustics stack from the Oppo HA-1 - to run cooler.

:wink:



I'm glad you're happy with the Equi=Tech BPT. That's more than I can spend for power conditioning, but I don't doubt it does a great job. They have a great reputation.
 
Last edited:
     Share This Post       
post-13694672
Post #36 of 532

knowhatimean

500+ Head-Fier
Joined
Jun 16, 2011
Messages
839
Reaction score
134
Joined
Jun 16, 2011
Posts
839
Likes
134
Hey!

Yes, I still use the wooden spools to separate my Metrum Acoustics stack from the Oppo HA-1 - to run cooler.

:wink:



I'm glad you're happy with the Equi=Tech BPT. That's more than I can spend for power conditioning, but I don't doubt it does a great job. They have a great reputation.
I seem to recall ,& 'seeming' to recall is becoming more frequent than I care to admit, I probably mentioned that I was using the Equi=Tech to you way back in the 'Aurix' thread.

To be honest the cost of it (even though it was a used unit) was more than I should have spent. No regrets though & I find it very relevant & worthwhile that you have been suggesting
this technology to others.

"Keep on, Keeping on"
Steve
 
     Share This Post       
post-13694766
Post #37 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
Thanks Steve!

I have to say, I'm not fully convinced on the subject of balanced power's advantages - in part because I've never given it a chance. I do, however, know that several references suggest that it offers a a few more dB of common-mode noise reduction, beyond that offered when the secondary is grounded at the Neutral (unbalanced) vs. at a center-tap (balanced).

More on that and back to the discussion of Isolation Transformers...

On the heels of retracting my long-held, dogmatic position (i.e. my ignorant and arrogant position) regarding grounded vs. floating secondaries' affect on Common-Mode vs. Normal-Mode noise reduction, I feared there was a good possibility that I was again leading readers astray as I stuck my neck out and posted the following response to abtr's question at ComputerAudiophile:

Quoting my summary of just about everything learned, thus far:

Hi Abtr,

This is my current understanding, eager for correction, where appropriate... :)

Whether starting out balanced (with the secondary grounded from a center tap) or unbalanced (with the secondary grounded at the neutral wire), if you then float the secondary, you will still get the same amount of common-mode noise reduction as you had before floating the secondary, with the only difference being that if you started out balanced, with a grounded center tap, you will have just converted it to an unbalanced transformer with a floating Secondary.

So... In your experience, you have essentially said you prefer the sound of an ungrounded (floating) secondary to the sound of a balanced secondary (which, by definition, is grounded via the center-tap.)

I suspect the reason you prefer the floating secondary is because you've got a ground loop between one or more components that gets attenuated somewhat when you float the secondary that they are all sharing.

I'm not a big believer in balanced power, perhaps because I so strongly believe that the "magic" of common-mode noise reduction occurs via the Faraday shield that inhibits capacitive coupling from the Primary into the Secondary. In other words, what work is left to be done, by the time the 60 Hz AC power has passed unharmed from the Primary through to the Secondary (via magnetic induction), stripped of any DC signals (Common-Mode noise) that have, at that point, already been attenuated 20,000,000:1 (-146 dB), in the case of the 0.0005 pF Topaz units? Whether we ground the secondary at a center tap (balanced) or ground it at the Neutral (unbalanced), the Common-Mode noise that came into the Primary on the Mains has already been diverted to ground by the Faraday shield(s), converting any residual common-mode into transverse-mode (normal- or differential-mode) noise - which most 1:1 transformers would just pass into your loads, but the Topaz Ultra-Isolators have some kind of double or triple Faraday shield configuration that manages to provide -65 dB of normal-mode noise reduction without using modern filter circuits (i.e. Y-Caps at the input, an X-Cap across the outputs (for modest voltage surges) or one or more serially arranged MOVs across the inputs or outputs (for heavy surge protection). Keep in mind that MOVs actually create some common-mode noise when suppressing normal-mode transients, and the Topaz can already absorb a lot of surge, at least until the voltages are high enough to saturate the transformer and penetrate the insulation of the windings. :)

OK, I got into a bit of a ramble, there, but to answer your first question... There are two reasons for putting only one component (one load) on a transformer with a floating secondary: 1) If you were to plug two components into one floating-secondary transformer, and the first component somehow shorted Hot to the case, you would be fine, until, by chance, at some point in the future, the other component shorted Neutral to its case -AND- you happened to touch both cases at the same time - allowing hot to flow into one hand over to the other hand. The probability of this happening is extremely low, but if the two components were plugged into the same transformer with a grounded secondary, you wouldn't have to worry about the improbable possibility. 2) Much more probable is the chance that you've got a DAC, CD Player, Blue-Ray player or other microprocessor-equipped component that's dumping digital "hash" common-mode noise back onto the power cord, where it could pollute the power going to any other component that's plugged into the same outlet, power strip, or transformer. You could also have one or more components that are equipped with SMPS, which are also known for dumping noise back onto the mains.

A well-made analog component, with a linear power supply, like an amplifier, is more likely to be a victim than a culprit, when sharing a power strip with other components, so these non-backwashing components can be plugged directly into a grounded-secondary transformer (whether balanced or unbalanced - your choice), but all the backwash suspects (DACs and other digital sources, plus anything with an SMPS) should be segregated from each other and from the analog components, by using floating-secondary transformers that themselves plugged into the one, larger capacity, grounded-secondary transformer. Each of the floating-secondary transformers will prevent any backwash noise from polluting other components - the common-mode noise attempting to flow upstream will be attenuated as it attempts to get from the secondary coil to the primary coil. (A transformer with Faraday shield can attenuate common-mode in both directions.)

It will also break ground loops - even if you have signal cables running between components - i.e. between a DAC and an amp - no loop can be formed to get back to a shared power ground when they are each plugged into independent, dedicated, floating-secondary transformers. Remember, each component with a three-prong plug still has a safety ground that goes all the way back to the wall outlet, through both transformers, per code, but neither the Hot nor the Neutral supplying power to each compoent is connected to that safety ground - at least not within their respective floating-secondary transformers. Joy!

You can, however suffer some leakage currents, caused by voltage differences coming out of their independent transformers - i.e. when an amp is plugged into the powerstrip of the big grounded-secondary transformer, but the DAC is plugged into a floating-secondary transformer that has been inserted between the DAC and the big transformer - the amp and the DAC will see different voltages, in which case, if you want to discourage leakage currents, you can really pull out all the stops and insert a high-bandwidth signal transformer, such as one of these, made by Jensen:

https://www.amazon.com/Jensen-CI-2RR-IsoMax-Isolator-Jensen/dp/B00ASVWYCS

or

https://www.amazon.com/Jensen-DM2-2XX-Iso-Max-Isolator-Jensen/dp/B00ASVWYO6

But to start with, I would encourage you to just ground the secondary of your main transformer (unbalanced is my preference), then insert Hammond 171 Series transformers (which range from 100 VA to 1000 VA and have floating secondaries) or a B&K Precision 1604A, ahead of each digital component or those with SMPS. Give that a try and see if it doesn't sound better than plugging everything into your single, floating-secondary transformer.

I would, however, caution you to use a Kil-A-Watt to measure the voltage going into each component when operating. Each transformer in a series will likely increase the voltage that came into it, even though they are technically 1:1, until you fully load them to their rated capacity - which you really don't want to do, especially for power amps, because you want to leave "headroom" for the transformer to supply instantaneous peak currents on demand, above rms current requirements.

If stacking two 1:1 transformers serially has your component seeing more than about 127V, you should consider getting an APC LE1200 voltage regulator, and setting it to an output voltage of 107V (the lowest of three available settings.) Plug your big grounded-secondary transformer into the voltage regulator, then the smaller floating-secondary transformer, and you'll measure something closer to 120V at the second transformer's output. :)
I've been apprehensively awaiting the correction I solicited at the top of that post - preferably from John Swenson or Superdad (Alex Crespi) of Uptone Audio, but today, I'm relieved to see Superdad's "Like" applied to that post. It's a very welcome seal of approval (relief from my apprehension), even if I were the only person who could see it - just knowing that I have not, again, stuck my foot in my mouth, teaching above my understanding. I'm still left wondering if Superdad hasn't withheld some minor objections, but I'll take it at face value.
 
     Share This Post       
post-13702317
Post #38 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
Ok, news flash: I've found that when using my OPPO Sonica DAC with a Metrum Acoustics Aurux headphone amp, the treble sounds noticeably cleaner when they are both plugged directly into the Topaz grounded-secondary transformer, having removed the B&K floating-secondary transformer (from the DAC). Apparently, the difference in AC voltage was encouraging leakage currents. (The DAC, on the B&K, was seeing a higher voltage than the amp.) Any "backwash" coming from the DAC (or ground loops) made possible in the absence of the floating-secondary IT on the DAC, are apparently inaudible, if they are an issue at all), relative to the audible leakage current noise, caused by unmatched supply voltages.

John Swenson has advocated plugging everything directly into the grounded-secondary Topaz (with low inter-winding pF rating), using a simple power strip, if necessary for more outlets, to reduce the impedance between each load. This has turned out to be great advice for my Sonica DAC + Aurix amp, but I still prefer the lower noise floor I get for other combos, by inserting the floating-secondary transformer in between the Topaz and the DAC (and again, for other digital sources.)

Moral of the story: YMMV! Experiment! But pay attention to the voltages when you put transformers in series. It helps to have the APC LE1200 voltage regulator - I had to bump the setting up to 120V for the Topaz powering both the Sonica DAC and Aurix amp, after removing the B&K 1604A from the DAC.
 
     Share This Post       
post-13702709
Post #39 of 532

uncola

1000+ Head-Fier
Joined
Oct 5, 2007
Messages
1,263
Reaction score
143
Joined
Oct 5, 2007
Posts
1,263
Likes
143
the interwinding capacitance problem, I think I read newer balanced isolation transformers have a shield tied to ground in between the primary and secondary winding that prevents it.. so is it still necessary to get the topaz with low interwinding capacitance transformers? I've ordered parts to put together my balanced isolation transformer but I think I Might have chosen the wrong transformer because although it has two secondary 58v windings, it doesn't have the shield tied to ground with ground wire to use :/
 
     Share This Post       
post-13704375
Post #40 of 532

johnzz4

500+ Head-Fier
Joined
Dec 31, 2009
Messages
663
Reaction score
422
Location
Worcester, MA, US
Joined
Dec 31, 2009
Location
Worcester, MA, US
Posts
663
Likes
422
So, I purchased a 0.0005pF Topaz transformer and experimented with it as a standalone solution, and also in combination with the PS Audio P3 regen. The sound with the Topaz in-line (with or without the P3) is smoother, but I wouldn't call it better. It seems transients and dynamics take a hit. An interesting data point is that when I plug the P3 into the wall directly, it reports 1.4% THD on the incoming power and 0.1% THD on the regenerated power. With the Topaz in-line before the P3, incoming power has 6.5% THD and regenerated power is at 1.6% THD. I'm not sure how important that is since I believe 1.6% THD is still quite good, but 6.5% I'm not so sure about. Anyone more knowledgeable on the subject have any thoughts on this data?
 
     Share This Post       
  • Like
Reactions: foreverzer0
post-13704450
Post #41 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
the interwinding capacitance problem, I think I read newer balanced isolation transformers have a shield tied to ground in between the primary and secondary winding that prevents it.. so is it still necessary to get the topaz with low interwinding capacitance transformers? I've ordered parts to put together my balanced isolation transformer but I think I Might have chosen the wrong transformer because although it has two secondary 58v windings, it doesn't have the shield tied to ground with ground wire to use :/
The last thing I want to do is discourage a DIY project - I have great respect for your skills, but I do have string doubts that you can achieve the 0.0005 pF inter-winding capacitance of the Topaz -31 and -32 models. John Swenson of Uptone Audio has made several posts about the need for a low capictance in a couple of ComputeAudiophile threads. All transformers suffer capacitive coupling of the coils.

As you've commented, here, a grounded Faraday shield can reduce the capacitive coupling, but there are many different ways to construct the shield, apparently, and some transformer designs have been made with double or triple Faraday shields. See articles and diagrams I've provided in earlier posts. Another variable is the distance between the coils - this alone will reduce the capacitive coupling, but does so at the expend of efficiency.


Most modern, commercially made isolation transformers have much higher pF ratings, if they are published at all. I've seen some with ratings of 10 pF to 40 pF - and that's with grounded Faraday shields. John Swenson has stated that these fail to do a good job of Common-Mode noise reduction in the higher frequencies where you need it the most. THE LOWER A TRANSFORMER'S CAPACITIVE COUPLING, THE GREATER THE ATTENUATION OF COMMON-MODE NOISE IN THE HIGH FREQUENCIES. See the curves charted in one of my first posts to this thread. It shows that attenuation is much greater in the lower frequencies. So, if you're only interested in noise reduction for a sub-woofer, then get a Tripp-Lite or Hammond isolation transformer. :wink:

So, you are basically trying to reinvent the proverbial wheel, when attempting out to replicate the design of a Topaz/MGE/Daitron 0.0005pF isolation transformer. It could still be a very fun project, of course.
 
Last edited:
     Share This Post       
post-13704470
Post #42 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
So, I purchased a 0.0005pF Topaz transformer and experimented with it as a standalone solution, and also in combination with the PS Audio P3 regen. The sound with the Topaz in-line (with or without the P3) is smoother, but I wouldn't call it better. It seems transients and dynamics take a hit. An interesting data point is that when I plug the P3 into the wall directly, it reports 1.4% THD on the incoming power and 0.1% THD on the regenerated power. With the Topaz in-line before the P3, incoming power has 6.5% THD and regenerated power is at 1.6% THD. I'm not sure how important that is since I believe 1.6% THD is still quite good, but 6.5% I'm not so sure about. Anyone more knowledgeable on the subject have any thoughts on this data?
Hi John,

That's great that you could make that comparison. Regarding the hit on dynamics, are you using a headphone amp or a much hungrier power amp? Is the VA rating of the Topaz transformer at least half again the combined VA consumption of all the gear that's plugged into it?

The THD measurements provided by the PS3 are a real head-scratcher, but for sure, no matter any degree of error, I would think it would at least be consistent, so 6.5% THD vs. 1.4% is a huge difference. It's enough to make me consider mailing you my Topaz for measurement, but I like what I hear, so I'll not burden you with that request. :)
 
     Share This Post       
post-13704522
Post #43 of 532

johnzz4

500+ Head-Fier
Joined
Dec 31, 2009
Messages
663
Reaction score
422
Location
Worcester, MA, US
Joined
Dec 31, 2009
Location
Worcester, MA, US
Posts
663
Likes
422
Hi John,

That's great that you could make that comparison. Regarding the hit on dynamics, are you using a headphone amp or a much hungrier power amp? Is the VA rating of the Topaz transformer at least half again the combined VA consumption of all the gear that's plugged into it?

The THD measurements provided by the PS3 are a real head-scratcher, but for sure, no matter any degree of error, I would think it would at least be consistent, so 6.5% THD vs. 1.4% is a huge difference. It's enough to make me consider mailing you my Topaz for measurement, but I like what I hear, so I'll not burden you with that request. :)
I'd be happy to measure if you change your mind. That way I can make sure there's nothing wrong with mine! I have a 70VA load - just a streamer, DAC and headphone amp. My Topaz is rated for over 200VA.
 
     Share This Post       
post-13706172
Post #44 of 532
Joined
Apr 28, 2007
Messages
5,493
Reaction score
1,059
Joined
Apr 28, 2007
Posts
5,493
Likes
1,059
I'd be happy to measure if you change your mind. That way I can make sure there's nothing wrong with mine! I have a 70VA load - just a streamer, DAC and headphone amp. My Topaz is rated for over 200VA.
That's very generous of you, truly, but my curiosity is overwhelmed by my laziness. It would be a hassle to box it up and ship it. Ignorance is bliss, in this instance. :) Thanks, though!
 
     Share This Post       
post-13706193
Post #45 of 532

pctazhp

Headphoneus Supremus
Joined
Sep 2, 2015
Messages
3,045
Reaction score
715
Location
Arizona
Joined
Sep 2, 2015
Location
Arizona
Posts
3,045
Likes
715
That's very generous of you, truly, but my curiosity is overwhelmed by my laziness. It would be a hassle to box it up and ship it. Ignorance is bliss, in this instance. :) Thanks, though!
A man after my own heart. I hate shipping stuff and I revel in ignorance :ksc75smile:
 
     Share This Post       
  • Like
Reactions: zilch0md

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top