Discussion of AC mains isolation transformers

[gererick]

I just got my Topaz 91002-12, all I should have to do is change the plug to fit a normal outlet and I should be good to test, correct?

[gererick]

7 minutes ago, diecaster said:

.005pF interwinding capacitance of your Topaz is not going to reduce common mode and normal mode noise as well as the .0005pF Topaz units.

 

You need to make sure it is wired correctly for the voltage you plan on using. Each side could be wired differently so you need to open it up and check that out. Just because it says both ends are 120v does not mean it is so.

 

Thanks, Diecaster,  I appreciate your reply. 

 

I'm aware of the reported improvement (according to some) in performance of .0005 vs .005, though John Swenson didn't feel this was meaningful per on an earlier post of his and uses a .005 (2nd post in this thread, which is why I went ahead and bought this). 

 

For now, I've got an inexpensive $175 unit I can try out while looking for a 31 or a 32 at a low price.  

 

I'll open it up and send pictures tomorrow, as I won't know by looking at it (opened up) what the voltages are, or what to rearrange in order to get the voltages right (if needed).  Because of the cord, the input side may be difficult to remove.  

 

Rick

 

 

[gererick]

I went ahead and opened the input, and the connections seem to be covered.  I have a 0 to 120 variac and a Kill A Watt, maybe change the plug and try low voltages while measuring the outlet with a meter?

 

 

[gererick]

Same situation on the outlet side.  Maybe I am looking at the wrong places?

[gererick]

The switch on the outlet plate is a 20 amp 125 Volt AC switch, to the extent that can be relied on.

[gererick]

Thanks for the replies, the Topaz seems to be working fine in my system but I will need to address the noise it makes, haven’t done thorough listening.  The main benefits seem to be mis and high at this early stage.  This is without the Tripp Lite PS3612–20HW, yet.  It has a black and white pigtail at each end with no ground pigtail and fortunately no circuit breaker.  There are two ground wires at each end which connect the last outlets to the chassis.  It has a knockout at each end.  I need to decide whether to hardwire it or to put an IEC on it so I can try different audiophile power cords.  Any thoughts?

[gererick]

Hi: I've bought a Elgar model 2.5-13.  It is 2.5kVa and .0005 pfd.  It appears to be the same as or very similar to a Topaz 91002-31.  

 

The input (from the wall outlet) is wired.

 

The output has to be wired.  Would the black and the white wires go in the same position that they are wired in the input?

[gererick]

28 minutes ago, oneguy said:

Very nice find!
 

The 20kv unit though will be a real gem though and worth its weight in audio gold. If you ever get internal pics I’d love to see them. You should wire it for balanced power. 

I have IT but it isn’t wired for balanced power.  What again are the risks of doing that?

[gererick]

36 minutes ago, gererick said:

I have IT but it isn’t wired for balanced power.  What again are the risks of doing that?

It is a 2.5 KVA .0001 pfd Elgar.

[gererick]

1 hour ago, Talley4217 said:

Both 120v on your 240v phasing is being used. Which is why you need an isolation transformer with good grounding and upgraded wiring to combat the noise found in your own home.
 

it's the grounding that kills your the most. Then it's the noise on the lines picked up from all the crap electronics with switching power supplies.    

According to Sound Application’s Jim Weil, it is transverse mode noise that kills your sound the most.  “Transverse Mode (TM) noise occurs only on the "Hot" in relationship to the "Neutral."
Common Mode (CM) noise is "in phase" noise present on both the "Hot" and "Neutral." ”  I still have an unbalanced IT at this point, though, and the system sounds very good.

[gererick]

5 hours ago, MarkusBarkus said:

...and having added one of Jim's TT7s just yesterday, he is on to something. 

The Sound Application unit only has six outlets - do you continue to use a power strip to cut down on impedance between boxes to lower noise generated by leakage loops?

[gererick]

1 hour ago, Talley4217 said:

Please don't take this as rude but I stopped reading at romex.  10 gauge is also no way near large enough.  Additionally 1.8kva is the reason your choked.  The topaz unit isolation ratings are based on operating within it's design.  When you stress over that design the you experience more issues.  Instantaneous peaks draws is something nobody talks about.  My system is very simple to a minimalist point of view and yet can still draw 32amps peaks under reference levels  (I'm into theater systems myself)   It tells me that it doesn't take much to overload these things.

 

Give me some more information on your circuitry.  How far are you feeding your outlet from the panel?  What does your load look like?  How much equipment what type?

From ray-dude’s post reviewing the SA conditioner:  “The line length from my electrical panel to these outlets is ~15', so extremely close proximity to my home electrical panel.”.   Regarding his system, it is shown at the bottom of his posts.  No amplifier, so presumably not a heavy load outside of his Extreme server.  His DAC drives his efficient speakers.  “ATT Fiber -> EdgeRouter X SFP -> Sonore opticalModule -> Taiko Audio Extreme -> Chord DAVE -> Voxativ 9.87 speakers w/ 4D drivers”.   That probably addresses your questions to ray-dude, though he may reply with more.

 

Reading recent posts, I probably don’t have my Elgar optimized.  I don’t experience dull dynamics that ray-dude experienced with his Extreme.  My system replicates dynamic-sounding instruments very well.

My Elgar IT is 120 in and 120 out.  It is not balanced.  Presumably if balanced I’d need a larger-than 2.5 KVA , but am nervous about balanced because I have a lot of tweaks, mainly from High Fidelity Cables, Audio Magic, and one other vendor that may not be right for a balanced circuit, I don’t know.  Regarding voltage, balanced, MOV, choke, caps and designing a filter, I would need to hire someone.  I can DIY a little, but not what is being discussed here, particularly given the importance of safety with the level of electricity involved.  My monobloocks draw roughly 425 watts each based on a reading from cheap device (a Kill-a-Watt, I think).

 

Any suggestions for what type of person to hire, in the southern part of Westchester County, NY?  
 

 

 

 

[gererick]

35 minutes ago, MarkusBarkus said:

...there's nothing grossly wrong with Romex for audio. Go with 10 gauge, if you can. It works great and it's within the comfort zone of any contractor and many DIY folks (this is not a guide to DIY electrical, so don't do it yourself if you aren't comfortable with it). Just getting a basic dedicated line like this will help. 
 

Are there better options? Yes.
 

Twisted pair BX (pre-made wire in flexible metal conduit) or even twisting up some THHN to pull through a flex conduit is good. But you should twist it up every foot or so, and put a piece of tape around it. Creating a "Conduit Transformer" by willy-nilly running cables, undersizing conduit, etc. is counter-productive.
 

I have 3/4" FMC (Flexible Metal Conduit) with stranded 10 ga. THHN wire. Not too difficult to run and "sounds" great.

 

For reference, my pull is about 35' end to end.

 

For fun, next week or thereabouts, I will pull a #6 copper, twisted, stranded, sheathed cable. 
 

Normal duplex outlets in the US will not accept more than 10 ga. wire, and even that can be a PITA. I don't like to pig-tail wire for audio (eg: run #6 or #8 and twist-up a joint with #10 to the outlet), so in this case, I've ordered some "special" outlets that will accept #6 conductors. 
 

Actually, my service is pretty good to start: 2/0 copper, 200 amp service. I have the network on one phase, audio on the other. Dedicated lines in each case. Home-run to the panel (end to end, no breaks). Audio stuff is on what I estimate to be the quieter phase, but any 220v device is on both legs. You can only do so much...but I do turn off the thermostat if I am listening carefully for some particular reason. Yes, I am that kind of freak. Ordinary listening: no.

I am in the city, NE US, so the grid is what it is. That is why I was looking into power supply options for audio. I was going to demo a Stromtank, but decided to go the TT7 route instead...or maybe to start. 
 

Is it expensive? It is indeed. More than my first four cars...combined. Although, full disclosure, my first was a '68 Opel Kadet wagon fixer-up I got for 50 bucks, which skews the data.
 

Some of the TT7 cost is due to economy of scale, some to IP, some due to materials. Jim is freaky-fastidious about the build. Call him up, if you have questions. You can't judge a device by its cover...or its weight. 

Thanks!  I have spoken with Jim but it is probably not a 2022 purchase.  I just bought (i) new speakers in September, (ii) parts, including a lot of Duelund caps, for a crossover upgrade for those speakers, (iii) a Synergistic Research Galileo Ground Block, and (iv) several other tweaks including higher-end QSA fuses.   Spending more than I should, which is why I’d prefer to optimize the Elgar IT as an interim solution.  In my case, dynamics don’t seem to be constrained, at least.

[gererick]

1 hour ago, MarkusBarkus said:

...there's nothing grossly wrong with Romex for audio. Go with 10 gauge, if you can. It works great and it's within the comfort zone of any contractor and many DIY folks (this is not a guide to DIY electrical, so don't do it yourself if you aren't comfortable with it). Just getting a basic dedicated line like this will help. 
 

Are there better options? Yes.
 

Twisted pair BX (pre-made wire in flexible metal conduit) or even twisting up some THHN to pull through a flex conduit is good. But you should twist it up every foot or so, and put a piece of tape around it. Creating a "Conduit Transformer" by willy-nilly running cables, undersizing conduit, etc. is counter-productive.
 

I have 3/4" FMC (Flexible Metal Conduit) with stranded 10 ga. THHN wire. Not too difficult to run and "sounds" great.

 

For reference, my pull is about 35' end to end.

 

For fun, next week or thereabouts, I will pull a #6 copper, twisted, stranded, sheathed cable. 
 

Normal duplex outlets in the US will not accept more than 10 ga. wire, and even that can be a PITA. I don't like to pig-tail wire for audio (eg: run #6 or #8 and twist-up a joint with #10 to the outlet), so in this case, I've ordered some "special" outlets that will accept #6 conductors. 
 

Actually, my service is pretty good to start: 2/0 copper, 200 amp service. I have the network on one phase, audio on the other. Dedicated lines in each case. Home-run to the panel (end to end, no breaks). Audio stuff is on what I estimate to be the quieter phase, but any 220v device is on both legs. You can only do so much...but I do turn off the thermostat if I am listening carefully for some particular reason. Yes, I am that kind of freak. Ordinary listening: no.

I am in the city, NE US, so the grid is what it is. That is why I was looking into power supply options for audio. I was going to demo a Stromtank, but decided to go the TT7 route instead...or maybe to start. 
 

Is it expensive? It is indeed. More than my first four cars...combined. Although, full disclosure, my first was a '68 Opel Kadet wagon fixer-up I got for 50 bucks, which skews the data.
 

Some of the TT7 cost is due to economy of scale, some to IP, some due to materials. Jim is freaky-fastidious about the build. Call him up, if you have questions. You can't judge a device by its cover...or its weight. 

Where would one order special outlets that will accept 6 AWG?

[gererick]

39 minutes ago, MarkusBarkus said:

...that would be fab. Can you imagine? (You did!). I looked into using the twist-lok fixtures for outlet/plug, which have good contact area, but kind of a hassle. 

@gererickI believe Jim Weil has the outlets. May be other sources too. I *think* his are Hubbells. 
 

Excellent Sunday exchanges, fellas! A lotta fun. Thanks! 

 

Thanks!  He sells wire also.  Not sure of the gauge, but less than 10 and probably a better quality conductor.

[gererick]

16 hours ago, Talley4217 said:

I'd argue that a well designed electrical system would prevent alot of transverse noise.  Isolation of power circuits and using high quality polyethylene insulated wire over the crap PVC that everyone else is using as a power delivery.  Romex is by far the worst wire you can possibly use and will itself induce problems if your looking for quality power delivery.

One thing that article doesn't mention is using a 240V split phase input with a 120V output.  Having 240V input ends up cancelling out alot of noise and is the preferred method for wiring these units.   120V in and 120V out will allow many transverse noise to pass through without filtration.

 

It seems that Step 1 for me would be to get a quote from an electrician to run a 240V line of 6 AWG from my panel to my IT, which is a hard-wired 2.5 KVA unit.  This would ostensibly lower transverse noise, particularly if the wire is high quality, and also provide more stable voltage.  The electrician would also have to know how to convert the IT so that it would be 240V input and 120V output instead of its existing 120V in / 120v out.  

 

It would be 38' of wire, easy to run because it would be strapped to the wall and ceiling of my garage, going through a single wall between my garage and my listening room, where it would run down the wall behind a diffuser in the front corner (thus hidden) and then along the wall (not hidden) until it gets to my transformer.  

 

RC filter and EMC filter TBD, given my lack of knowledge as to what is needed and how to execute.  Converting to balanced also TBD.

 

Hopefully that captures most of what I can do.

[gererick]

20 hours ago, oneguy said:

Where did you read that the T1 topaz units have MOVs inside? I’ve only seen a capacitor to aid in reduction of transverse noise when I open them up. 

I have not seen a capacitor when opening either end of my IT.  Is it typically visible?

[gererick]

1 hour ago, oneguy said:

With the topaz T1 units it’s visible but I can’t speak to others. The T100R did not have one installed and not all T1’s have it installed. From

what I have seen it seems more prevalent in the receptacle version vice the terminal version but both have come from the factory with them. Capacitor sizing for this task is talked about here:

https://www.surplussales.com/Transformers/Pdfs/tp-91407-11.pdf

 

The topaz units come with an Aerovox brand capacitor. Here’s a pic of one installed from a T1 that I opened up:

That’s interesting!

 

I have a black, white and green wire (with the typical convention of hot, neutral, and, ground, respectively) exiting the transformer (after having been correctly wired to the correct locations on the transformer) and meeting up with the same color conventions on a power strip via a hard wire connection at that end also.
 

Let’s say, working with an electrician or more likely an electrical engineer, that somewhere along that path but probably close to the connections on the transformer, we wanted to cut certain wires and put that capacitor (of the correctly calculated value) between them, which wire would ‘go into’ the capacitor and which wire would the output of the capacitor go to? 
 

Or is this effectively just a capacitor pigtailed between the white-and-black / hot-and-neutral?

 

Not sure what the green wire’s purpose is.

 

I will try not to ask too many more layman-type questions after you respond but will instead show your post to an electrical engineer, who may already know what is going on by looking at the photo in your post.

 

Thanks again!

[gererick]

23 minutes ago, oneguy said:

It’s AC so it just needs to span the hot and neutral side. 
 

The green wire provides the ground connection and I suspect conduit to shunt the noise through. If you do go balanced power and decide to use 120v input from the wall then the output side of the transformer will need to be grounded halfway through the output windings to make the balanced power. Grounding halfway through makes two 60v wave forms 180deg out of phase so a total of 120v of potential between them. 

Thanks!  What I meant by 'Not sure what the green wire's purpose is' was that it seemed to be connected to the outlet on each end of the short wire.  Is one end connected to a ground screw and the other to a hot screw?

[gererick]

On 1/17/2022 at 5:18 PM, oneguy said:

It’s AC so it just needs to span the hot and neutral side. 
 

The green wire provides the ground connection and I suspect conduit to shunt the noise through. If you do go balanced power and decide to use 120v input from the wall then the output side of the transformer will need to be grounded halfway through the output windings to make the balanced power. Grounding halfway through makes two 60v wave forms 180deg out of phase so a total of 120v of potential between them. 

If, hypothetically I am using 60% of the 2.5 KVA at present (I am probably using close to 1.1 KVA as the amps draw ~850 watts), and I convert from unbalanced to balanced, will I still be using 60% of the transformer's rated output?

 

I may have read this being addressed somewhere in the thread a few years ago, but not sure if it was addressed in the manner that I am asking it.  It may have been.

[gererick]

35 minutes ago, oneguy said:

What you must primarily consider is these are rated in VA which is not the same as watts (V x A). 

The Kill-a-watt power measuring devics will output VA as well as tell you your PFC but as mentioned before their sampling rate is not great for capturing the short spikes that dynamic parts in music may cause.

 

It’s hard to make a conclusive recommendation because best case scenario if you assume you are using 850w and pf=1 then 850 is your VA. If there is any reactive load then pf will not equal 1 and VA will be higher. 

 

To answer the question you were driving at though, I plan on the rating being cut in half when wiring for balanced power because you are now using the 240v wiring configuration. The reason being is the 240v wiring configuration can only take half the amperage of the 120v wiring configuration. Anyone else have any differing thoughts?

Oneguy, thanks!

 

While waiting to see if / how others respond, the implication of your response seems to be that if 120V in and 120V out and 60% of rated KVA is being used (more than that for music spikes), and I convert to balanced with no change in voltage-in, I would not need to buy a 5.0 KVA isolation transformer because I am still at 60% of rated KVA.

 

If I both convert to balanced and to 240V in and 120V out, then I may need to buy, for instance, a 5.0 KVA rated IT.

 

My Elgar IT has 0.0005 pfd capacitance.  I'm not sure how easy it would be to find that in a more powerful isolation transformer at an acceptable cost.   

 

One option would be to buy 6 AWG, stay at 120V in, and execute a capacitor installation as discussed previously.  That option is of course available whether 240 in or 120 in.

[gererick]

1 hour ago, oneguy said:

No, if you intend to used 120v in to the IT and convert it to balanced power on the output you have to wire the transformer for 240v in and out  then ground the midway point on the output coils to get balanced power. So in the below diagram I would jumper H2 to H3, jumper X2 to X3, ground either X2 or X3(doesn’t matter which) and then you would be set up for balanced power when 120v in is applied. I would only put 1.25KVA through your 2.5KVA transformer in the configuration. 

 

f you want 240V in and 120V balanced out you will need a transformer that accepts 480v in and 240v out / 120v out. It would be wired in the 480 in / 240 out config and grounded on the output as described above. It would be fed 240v in and give you 120 v out. You need the 2:1 step down from input to output and you need to be able to create 2 waveforms of equal amplitude 180 deg out of phase which is what the grounding does. 

"If you want 240V in and 120V balanced out you will need a transformer that accepts 480v in and 240v out / 120v out. "

 

Sorry I am not following, due to a lack of knowledge.  But in the scenario stated above, is the "120v out" 60v on the hot and 60v on the neutral?

[gererick]

21 hours ago, oneguy said:

@gererickExcuse the the chicken scratch. This may help better convey what I’m trying to pass. 

oneguy, thanks for the drawing!  I'll need to get some outside help in order to understand it fully.  

 

In my panel, I can have someone combine two single 15 amp breakers into one breaker that has two 15 amp breakers in it, in order to make room for a breaker in my panel that can handle 240V and six AWG.  I will go ahead and order some 6 AWG.

 

For now, the plan will be to go into the isolation transformer with 240V and out with 120V (after reconfiguring it from "120 in; 120 out"), unbalanced, as my isolation transformer is not 'big' enough if its KVA gets reduced by 50% in a balanced configuration.

[gererick]

On 1/16/2022 at 1:13 PM, ray-dude said:

I should note that my write ups are a snap shot in a long system evolution (Reality Quest).  Those power experiments pointed the way to improvements, that's for sure, but the dedicated line (even with romex) was a huge step forward from what I had before - at the time I put those in several years ago it was one the more significant system improvements I'd heard up to that point (who knows whatever house crap was on the shared line before then).

 

As a quick update, since my TT7 write up last year I moved into a new home, and used the opportunity to upgrade to 6AWG cabling from the electrical panel to my outlet (~20' run, in conduit).  Obviously not possible to do an A/B any more, so I can't speak to impact, but my experience with the Sablon power cords certainly gave me VERY high confidence to go with heavier gauge wiring in the walls.  If you can swing it (and find an electrician to help you with it without laughing at you), a very cost effective way to get a big impact across your system.

 

As FYI I did get the outlet and wiring from Jim.  He spoke about how challenging it was to get the wires connected to the outlet, but that it could be done with persistence.

 

I also have been doing a lot of experiments with power buffering and power regulation. Astonishing how much lift there is to be had by doing everything you can to stabilize power (AC and DC) under dynamic load, external to components and internal to components.  I'm nowhere near the summit on this stuff, that's for sure.

 

I should note that everyone's power experience is very very different, even if the toolkit is the same.  At the end of the day, everyone has a different electrical grid, home wiring, etc, so the best advice is use best practices, and see which best practicers are "bester" in your setup.  Pay attention to these, and try other best practices that double/triple down on that aspect of power hygiene (alas, now that I've moved to a new home/neighborhood, it is time to repeat that process....ug)

In your 6 AWG 20' run in conduit, I assume the conduit was PVC or rough equivalent?

[gererick]

7 hours ago, Talley4217 said:

Ideally you would run the isolation transformer 24/7 but depending how you wire it up the idle load can vary.  My 7.5kva wired normally consumes 1140w at idle so I usually just turn it off when I'm not using the system.  Thats like running a vacuum cleaner 24/7 and can easily add 40-60/mo on your light bill.

This unit is so scary silent it's probably only putting out 15-20db.  I can move this into my room it's that quiet.  Insane!

This topaz at 210w for my rate will add 14/mo but is actually less than my current setup.  Happy savings :)

Wow, congratulations!  Other than KVA, were specs better on the just-purchased unit compared to the existing 7.5 KVA?  I assume you were running the 7.5 KVA balanced?