Balanced Power

[Ralf11]

http://www.6moons.com/audioreviews/equitech/1.html

[Charente]

Thank-you for the link @Ralf11 ... interesting reading. I'm already a Balanced Power Supply convert and even with my comparatively rather more modest Airlink Transformers BPS, the results are still quite remarkable. 

[Speedskater]

While 6moons does wonderful coverage of hi-fi shows and new products, their technical competence is extremely low.

[Cornan]

Here is a schematics of a truly remarkable balanced isolation transformer IME. The switch set to a floating instead of grounded center-tap makes a huge difference for the better in terms of SQ. 

 

[Ralf11]

11 hours ago, Charente said:

Thank-you for the link @Ralf11 ... interesting reading. I'm already a Balanced Power Supply convert and even with my comparatively rather more modest Airlink Transformers BPS, the results are still quite remarkable. 

 

 

I wonder if balance power is better than a good isolation transformer?  It sure is a lot more $$, maybe due to the many used  isolation transformers available.

 

The other thing is the the retail cost relative to the parts cost...  

[mansr]

1 hour ago, Ralf11 said:

I wonder if balance power is better than a good isolation transformer?  It sure is a lot more $$, maybe due to the many used  isolation transformers available.

Huh? An isolation transformer output is by definition balanced.

[Cornan]

4 hours ago, mansr said:

Huh? An isolation transformer output is by definition balanced.

 

A isolation transformer have unbalanced output since the center tap is usually ungrounded if it is not called balanced power supply or similar. Most ITs can be rewired for balanced power by grounding the center tap  though.

[yellowblue]

If you are interested in balanced power you should look at the Plixir power conditioners. I am using the BAC400 and it was a worthwhile investment (even if I can´t compare it with other power conditioners).

https://www.plixirpower.com/pages/plixir-power-concept

[Cornan]

12 minutes ago, yellowblue said:

If you are interested in balanced power you should look at the Plixir power conditioners. I am using the BAC400 and it was a worthwhile investment (even if I can´t compare it with other power conditioners).

https://www.plixirpower.com/pages/plixir-power-concept

 

Nice ones!  

I have wonder for a while how difficult (and how expensive) it would be to build a balanced isolation transformer with DC outputs, ie skipping all the external DC PSUs and having one with 4-5 variable DC outputs using linear voltage regulators? It would save a lot of the extras!  

[Charente]

40 minutes ago, yellowblue said:

If you are interested in balanced power you should look at the Plixir power conditioners. I am using the BAC400 and it was a worthwhile investment (even if I can´t compare it with other power conditioners).

https://www.plixirpower.com/pages/plixir-power-concept

 

Nice ! ... makes my Airlink Transformers BPS look cheap by comparison ! ( https://airlinktransformers.com/product/standard-balanced-power-supply-bps1502 )

[jabbr]

13 hours ago, Ralf11 said:

 

 

I wonder if balance power is better than a good isolation transformer?  It sure is a lot more $$, maybe due to the many used  isolation transformers available.

 

The other thing is the the retail cost relative to the parts cost...  

Balanced is essentially a subset of isolation with specific wiring. A good balanced system needs a good isolation transformer as it’s basis.

 

Not everyone is comfortable nor knowledgeable enough to safely nor properly wire, gfci etc, so the retail cost reflects the knowledge, certifications etc.

[mansr]

There seems to be some confusion around what exactly the term balanced means. A transformer with a floating secondary is balanced in the sense that neither output terminal is fixed to ground (or any other) potential. A grounded centre tap is sometimes used as a safety measure. If the differential voltage is 120 V, both sides are limited to a harmless 60 V relative to ground. If, however, the goal is to isolate the load from external interference, a floating secondary is probably more effective.

[Ralf11]

7 hours ago, jabbr said:

Balanced is essentially a subset of isolation with specific wiring. A good balanced system needs a good isolation transformer as it’s basis.

 

Not everyone is comfortable nor knowledgeable enough to safely nor properly wire, gfci etc, so the retail cost reflects the knowledge, certifications etc.

 

any thoughts about its efficacy for improving SQ vs. a 'simple' isolation transformer?

(and welcome back BTW)

 

mansr - those selling balanced supplies for audio are using the term differently, hence my OP

[Speedskater]

It seems that a whole bunch of different situations are getting  co-mingled together. For a permanent hardwired AC balanced power system the NEC has a bunch of rules as to what is permitted.  For a smaller portable plug-in unit, the UL has other rules that the unit needs to tested to.

As I wrote in another thread the differences between an isolation transformer and a balanced transformer are very small.

[Abtr]

7 hours ago, mansr said:

There seems to be some confusion around what exactly the term balanced means. A transformer with a floating secondary is balanced in the sense that neither output terminal is fixed to ground (or any other) potential. A grounded centre tap is sometimes used as a safety measure. If the differential voltage is 120 V, both sides are limited to a harmless 60 V relative to ground. If, however, the goal is to isolate the load from external interference, a floating secondary is probably more effective.

 

Yes. And with a floating secondary you should connect all audio system  grounds/chassis to the secondary center tab (null reference) of the balanced mains isolation transformer for effective cancelation of rectifier noise from power supplies. And you should install a 2 pole RDC/GFCI at the output of the floating secondary for safety. Your central GFCI will not see a potentially dangerous short to chassis after a floating mains IT.

 

Also note that according to John Swenson (Uptone audio) any DC power supply without an AC mains ground connection can be beneficially 'grounded' by simply connecting the negative pole of the DC output to the mains ground (or the center tab of a balanced mains IT). I didn't try this myself. I use only one audio power supply without a mains ground connection; a Schiit transformer unit that outputs 16V AC (not DC) into a Schiit Modi multibit DAC. I tried 'grounding' the chassis of the DAC without noticeable SQ benefits. Maybe I should open the DAC and ground the negative DC rail inside..

[Cornan]

23 minutes ago, Speedskater said:

As I wrote in another thread the differences between an isolation transformer and a balanced transformer are very small.

 

I do not know what you call small differences, but to me there are clearly audioble differences between isolation transformers in general with balanced isolation transformer with floating secondary sounding quite a bit better than Ultra IT (with grounded secondary) and IT with floating secondary (that I also own). 

 

[Cornan]

30 minutes ago, Abtr said:

 

Also note that according to John Swenson (Uptone audio) any DC power supply without an AC mains ground connection can be beneficially 'grounded' by simply connecting the negative pole of the DC output to the mains ground (or the center tab of a balanced mains IT). I didn't try this myself.

 

All my DC power supplies are floating and IME after trying the JSGT everywhere it is only beneficial on the PSU powering my Aqvox switch (floating SMPS) and main router (floating LPS). In other spots it have made the sound worse.

[Speedskater]

17 minutes ago, Cornan said:

 

I do not know what you call small differences, but to me there are clearly audioble differences between isolation transformers in general with balanced isolation transformer with floating secondary sounding quite a bit better than Ultra IT (with grounded secondary) and IT with floating secondary (that I also own). 

 

It's my reading of papers by the experts on the subject. Start with Jim Brown and Bill Whitlock.

 

Tell me about how you dealt with all the uncontrolled variables when you did the comparison.  Any measurements?

 

It's real easy to measure signal-to-noise ratio at your amplifier's speaker terminals.

[Cornan]

Just now, Speedskater said:

It's my reading of papers by the experts on the subject. Start with Jim Brown and Bill Whitlock.

 

Tell me about how you dealt with all the uncontrolled variables when you did the comparison.  Any measurements?

 

It's real easy to measure signal-to-noise ratio at your amplifier's speaker terminals.

 

I am not into uncontrolled variables. I use my own ears and let them decide what they like or not, and they definately like balanced IT with floating secondary. Music glow and transparency in loads! ?

 

I wouldn't mind if you educated me how to measure real time SNR at the speaker terminals (using active speakers with balanced XLRs though) or headphone output. I am always willing to learn how to! ?

[hurka]

I don't know this balanced voodoo,but my experience:

Each rectifier get own transformers-own isolation transformers,(Cable length Between 30 cm!!!!!!)

Example,my amp inner power wire,power switch taked out,L and R side maked new holes,near the transformers,connected the isolator with short cable.Preamp maked the same,digital volume control 

 the same.Much much better than only one big isolator far away.

[Cornan]

4 hours ago, hurka said:

I don't know this balanced voodoo,but my experience:

Each rectifier get own transformers-own isolation transformers,(Cable length Between 30 cm!!!!!!)

Example,my amp inner power wire,power switch taked out,L and R side maked new holes,near the transformers,connected the isolator with short cable.Preamp maked the same,digital volume control 

 the same.Much much better than only one big isolator far away.

 

Great stuff! There is something very special with isolations in series (dual floats) IME. I can imagine that it sounds even better if you'll get the first isolation as close to the source as possible. Dual floats gets even better when combined it with a single star-earthed PSD post the big IT IME.  

[hurka]

1 minute ago, Cornan said:

 

Great stuff! There is something very special with isolations in series (dual floats) IME. I can imagine that it sounds even better if you'll get the first isolation as close to the source as possible. Dual floats gets even better when combined it with a single star-earthed PSD post the big IT IME.  

If you have many very expensive power cords(I don't have),not sure  my isolation method helps.

 

 

 

[Cornan]

33 minutes ago, hurka said:

If you have many very expensive power cords(I don't have),not sure  my isolation method helps.

 

 

 

 

I see power cords as a window. Better cables is no guarantee for a cleaner glass. You can get frosted glass, tinted glass, AB glass etc that masks the faults of your setup and let you see only the good stuff. I personally like starquad ac mains cable for one perticular reason. IME they have a clear window and do not mask faults as much as many other power cables do. They are realatively "cruel" cables but lets you find the source to the problem. If it does´nt sound good you just need to look elsewhere to find the root to your problems. When you have solve it the starquad power cables rewards you with a big smile and a lesson learned! FWIW.

[jabbr]

21 hours ago, Ralf11 said:

 

any thoughts about its efficacy for improving SQ vs. a 'simple' isolation transformer?

(and welcome back BTW)

 

mansr - those selling balanced supplies for audio are using the term differently, hence my OP

There are many advocates for various grounding schemes which insist that there is only one best way. 

 

Yes Brown and Whitlock are great starting points. 

 

I personally use Equi-tech balanced for my audio but also use floating and traditional isolation transformers in various situations.

 

Good design, solid isolation and avoidance of cheap SMPS goes a long way. 

 

Ideally you could try dystems and see which has had the best SQ — I think that many of these debates are system dependent assuming solid components are being used.

[Cornan]

18 minutes ago, jabbr said:

There are many advocates for various grounding schemes which insist that there is only one best way. 

 

Yes Brown and Whitlock are great starting points. 

 

I personally use Equi-tech balanced for my audio but also use floating and traditional isolation transformers in various situations.

 

Good design, solid isolation and avoidance of cheap SMPS goes a long way. 

 

Ideally you could try dystems and see which has had the best SQ — I think that many of these debates are system dependent assuming solid components are being used.

 

Very very true! No system is equal. God knows my system is not like many others. In my system balanced IT with floating secondary is awesome. Who knows if it will improve as much in a completely different system?  It is simply too many variables involved. Starquads, star-earth, LT3045s, DC blockers, ac mains voltage regs etc etc. You'll need to be Jim Brown or Bill Whitlock to know for sure! ?