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Discussion of AC mains isolation transformers


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11 hours ago, jsawyer09 said:

After a recent move, I discovered (forgotten) I had a couple of Topaz Ultra-Isolator Noise Suppressors (91095-31 and a smaller VA unit, 1/811T35S5R). After reading up on this with some interest, I was wondering if there would be any benefit of plugging my Google Home router and EtherRegen/LPS combo into the 500VA version with the 0.0005 pF? 

Routers are electrically noisy devices thankfully driven by 12V DC usually, sometimes 19.5V like my rotten Asus unit. There are EMC filters that are designed for DC use, since noise can be conducted from the router through the power supply and poison the AC to the audio equipment. The Topaz kills common mode from the primary to the secondary, so will block the remaining noise the filter escapes in the 70-120kHz range. Kind of difficult to measure all this. How the units are grounded is always critical. The Topaz has enough drive for the router / ER/ LPS or any combo thereof.

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Thank you, @One and a half. Your posts in this have been invaluable. There was thought about placing something like the PowerVar IT somewhere before or after for filtering and surge protection as well, but I can always utilize that unit for AV or in the garage. 

I also have a PS Audio Power Regenerator in my system, and had thoughts of placing another Topaz after it (with everything plugged into the PS Audio; the PS Audio into the Topaz; the Topaz into the 20a outlet on a dedicated line), but reading a few threads online (PS Audio forum, here and Head-Fi mostly) made my head spin, so really don't know what to do, honestly, thus abandoning the idea altogether. At the very least, I figured killing the noise from the network (router, switch) would in theory reap benefits. 

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I do recall reading that others have tried the combo PS Audio Regenerator and Topaz (with a simple plug in strip--see John Swenson in Uptone's forum on this site for more); if I better  understood how these units worked--enough to offer an opinion--I would, but I can say look on Audiogon forums, too, if you haven't for a similar discussion.

In a somewhat relevant comment, replacing the outlet on the Topaz, the outlet on the wall, the power chord (mine was connected internally with a couple of screws) to the wall and its plug each made a welcome difference. There have been a million words written on which bulk cord to buy, which plugs to buy and how different combinations sound... I used Cruz plugs and while there are undoubtedly better sound wall plugs out there, I've been happy enough with these to address needs in other areas.

 

As One and a Half said, routers are noisy beasts, so for it, I added a Keces p3 to handle its DC power needs, a Ghent DC power chord, and upgraded the power cord and plug for it, too. All to the good. 

 

 

iMac 27" with local music files > Audirvana 3.2.6 > Ethernet > MicroRendu (with LPS-1)> Schiit Yggy > Ayre K5 XE MP Preamp > Ayre v5 Amp > Aerial 10-T Speakers. PC's, SC's and  IC's all Cerious Technology, except Elrod EPS 2 to Ayre Pre and Ghent DC cord for M/R. 3 Ingress Audio Engineering Aluminum rollerballs and bearings under all except 4 under Yggy and 0 under Amp. Topaz 1k Iso, BPT power center with Cardas Myrtle block under. PS Audio wall plug, dedicated 20 amp run to equipment, second dedicated 20 amp run to distant iMac/Router, BK Precision 1604 for Netgear GS-1405 Switch, JSGT for M/R and Switch.

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I've read some of those alterations to the Topaz as well. I think that's a bit too much for me. My audio room has dedicated 20a lines, and I switched each of their outlets out with a combination of Furutech GTX-D(R) and Oyaide R0 varieties. I feel anything else at this point would be overkill if it already isn't. 

My router is a Google Nest. I don't have a linear PSU on it as of yet, but my switch(es)—an EtherRegen and/or English Electric 8—is powered by a Paul Hynes SR4 with the silver DC lead. To keep the router's SMPS separated from the LPS/switch, I think the option to use one Topaz for the router and one for the LPS/switch might be a good one from what I'm reading.

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You might try one Topaz with an inexpensive plug-in strip for both the router and LPS switch--just a thought--then compare to SQ using separate Topaz units as you've described. You might end up with a Topaz available for duty in another part of the system. 

 

Wherever it ends up, your system has a lot of excellent pieces so I bet it sounds great whatever you do. 

iMac 27" with local music files > Audirvana 3.2.6 > Ethernet > MicroRendu (with LPS-1)> Schiit Yggy > Ayre K5 XE MP Preamp > Ayre v5 Amp > Aerial 10-T Speakers. PC's, SC's and  IC's all Cerious Technology, except Elrod EPS 2 to Ayre Pre and Ghent DC cord for M/R. 3 Ingress Audio Engineering Aluminum rollerballs and bearings under all except 4 under Yggy and 0 under Amp. Topaz 1k Iso, BPT power center with Cardas Myrtle block under. PS Audio wall plug, dedicated 20 amp run to equipment, second dedicated 20 amp run to distant iMac/Router, BK Precision 1604 for Netgear GS-1405 Switch, JSGT for M/R and Switch.

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2 hours ago, jas said:

You might try one Topaz with an inexpensive plug-in strip for both the router and LPS switch--just a thought--then compare to SQ using separate Topaz units as you've described. You might end up with a Topaz available for duty in another part of the system. 

 

Wherever it ends up, your system has a lot of excellent pieces so I bet it sounds great whatever you do. 

Thank you, @jas. I have a few options, I think. I thought maybe placing the router/SMPS and switch/LPS on the same strip was a bad idea; better to isolate the two with two different Topaz units. You're right, though, in that I could just compare to see if there's any perceivable difference. That way I could free one up—as you say, and what @One and a halfmentions right after you—in order to experiment with the PS Audio regenerator if I wish to try at some point.

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1 hour ago, One and a half said:

If you wish to keep the PS AUDIO:

Buy a regular non surge rated power strip and connect to the secondary of the Topaz. Plug all your audio devices into the power strip.

Connect the primary of the Topaz to a ‘high’ current output on the Ps audio.

 

This method will clean up common mode noise from the PS Audio.

 

Just using the Topaz

Dedicated line —-> Topaz ——> Power Strip —-> audio devices. Further noise can be reduced with balanced output on the Topaz. Please read back in this thread on restrictions with this system.

 

For routers and other such noisy IT equipment, it’s better to isolate the Ethernet than power side with a nice linear supply. That linear supply will slow the progress of noise AC upstream, but the router will still carry rubbish on the Ethernet signal. Common mode a lot. Either EtherRegen or a BAAS filter or both work nicely to tame that noise.

Use a different circuit for IT gear not the audio dedicated line.

I really like the PS Audio and what it brings to my system. In all honesty, I don't believe I have a whole lot of noise, so to speak; however, I'm not certain I'd know what that sounded like in real-world terms anyway. My system is pretty resolving and as silent as I can remember it ever being at this point. I just figured since I have the iso-trannies around I could see if there's a further improvement SQ-wise, especially with regard to the network, since so much is talked about in terms of router and other networking noise being dumped back onto the line.

I do have a couple of non-suppression-type strips (one a NANA/Wiremold strip for Naim gear from long ago and a Tripp-Lite as well), so your former example above might be a good option to try, depending on how things go 'upstream' with the router and switch on one of the Topaz ITs.  

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59 minutes ago, jsawyer09 said:

 In all honesty, I don't believe I have a whole lot of noise, so to speak; however, I'm not certain I'd know what that sounded like in real-world terms anyway.

Common mode noise is simple to demonstrate in a USB transmission. Pick a laptop, printer cable and your favourite USB DAC.

 

Pick music that has vocals, piano, drums, percussion, bass, with not so much synth, a good stereo recording. The instruments should be easy to discern, Redbook is fine.

 

Listen and watch for:

a) Stage Height (are the vocals at the top line of the speaker or above it, how high a foot, two feet?)

b) Instrument placement (drums at the rear, maybe guitar at the side)

c) Treble splash (it's irritating)

d) Sibilants (usually on the recording)

e) Front to back placement. Some speakers are good at this, others not so, also depends a lot on the recording.

 

If that system sound's like mono, collapsed, that's common mode noise messing with the DAC.

 

Change to a different USB cable, the regular one you use and notice the difference. The cable's geometry will attenuate (or make worse) common mode noise that will change a - e.  

 

Whether you use a Topaz, Regenerator or a power strip in the wall with nothing, it's still critical to have all the audio equipment and their power supplies plugged into the same AC distributor/power strip. If one component's AC cable is too short, use an extension cable. This keeps the ground wire in the audio equipment at the same potential known as star wiring (can google it). This avoids ground loops.

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14 hours ago, One and a half said:

Use a different circuit for IT gear not the audio dedicated line.

Good info re: power @One and a half. Thank you. I did run a dedicated line for the IT closet, and put it on the opposite phase of the audio dedicated line.
 

The network gear is connected to the audio gear via fiber.
 

All the motor/compressor based devices are on the non-audio phase too.
 

Obsessive? You betcha! Thanks again for the interesting power info. Always a pleasure to read. Cheers...

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12 hours ago, One and a half said:

Whether you use a Topaz, Regenerator or a power strip in the wall with nothing, it's still critical to have all the audio equipment and their power supplies plugged into the same AC distributor/power strip. If one component's AC cable is too short, use an extension cable. This keeps the ground wire in the audio equipment at the same potential known as star wiring (can google it). This avoids ground loops.

Sound advice here, @One and a half. I have a pretty much all Naim system, save for a DSP unit, LPSs and the PS Audio, so I'm very careful to keep things grounded properly. I've been fortunate to this point not to have any ground loop issues. In fact, any sound emanating from my speakers' tweeter or drivers with nothing playing is eerily silent (Spendor D7s); you have to get within 2 inches or less to even hear a very faint/muted hiss. Naim amps have a history of mechanical transformer hum, and even that is silent. 

BTW, thanks for the tips on what to listen for. That helps put things into perspective. 

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On 3/11/2021 at 1:51 AM, jsawyer09 said:

Sound advice here, @One and a half. I have a pretty much all Naim system, save for a DSP unit, LPSs and the PS Audio, so I'm very careful to keep things grounded properly. I've been fortunate to this point not to have any ground loop issues. In fact, any sound emanating from my speakers' tweeter or drivers with nothing playing is eerily silent (Spendor D7s); you have to get within 2 inches or less to even hear a very faint/muted hiss. Naim amps have a history of mechanical transformer hum, and even that is silent. 

BTW, thanks for the tips on what to listen for. That helps put things into perspective. 

I wish there was an easy way to measure these effects, ears seem a good approach so far within reach of everyone.

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17 hours ago, One and a half said:

I wish there was an easy way to measure these effects, ears seem a good approach so far within reach of everyone.

No doubt. So far they haven't let me down. They've served me for both good and bad. 

So, as an update, I was able to split the duties of my network between the Topaz ITs then plug the router, switch and LPSs into a Tripp-Lite strip, then the strip into one of the Topaz units. I could detect no discernible differences at all. I thought about putting them in series, but am not real comfortable in doing that since they are different VA ratings; I don't want the risk. In addition, one has a greater inter-winding capacitance (.0005pF vs. .005pF—not certain there's a huge difference there in real-world terms; plus even if there were, would that somehow 'degrade' the signal clean up and negate any benefit one is trying to achieve in the first place?). So I have a spare unit, really. However, there's no way I would place it in the same room as the rest of the system, as they are quite loud.  

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There areAS  posts regarding loud hum in Iso transformers. One solution called for tightening the bolts, among other suggestions...I suggest this because one of my units is within two feet (though low sitting and nearly out of sight) and I near nothing from it. My second one does emit a low level hum, heard within 2 feet, so it sits in a wood cabinet and does not affect the listening experience. I did try connecting my Ayre amp to it (1k Topaz) and heard a noticeable hum loud enough that it did effect my listening experience. Not sure this is of much help as load may not be relevant in your case. Both are .0005pF units

iMac 27" with local music files > Audirvana 3.2.6 > Ethernet > MicroRendu (with LPS-1)> Schiit Yggy > Ayre K5 XE MP Preamp > Ayre v5 Amp > Aerial 10-T Speakers. PC's, SC's and  IC's all Cerious Technology, except Elrod EPS 2 to Ayre Pre and Ghent DC cord for M/R. 3 Ingress Audio Engineering Aluminum rollerballs and bearings under all except 4 under Yggy and 0 under Amp. Topaz 1k Iso, BPT power center with Cardas Myrtle block under. PS Audio wall plug, dedicated 20 amp run to equipment, second dedicated 20 amp run to distant iMac/Router, BK Precision 1604 for Netgear GS-1405 Switch, JSGT for M/R and Switch.

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Hi, @jas. I haven't gotten that far yet, but have read about tightening the bolts to good effect. Luckily, where these are used are quite some distance (three floors separated) away, so transformer hum is a non-issue. However, if I want to utilize one in my listening room as has been discussed here, then yes, I'll have to see if something can be done to mitigate the noise or come up with a soundproofing method. One of them is more of a culprit than the other; unfortunately it's the one with lower inter-winding capacitance and higher VA value. Not that it's a deal-breaker in the overall scheme of things. -130-ish dB versus -146 dB drop in noise is still commendable no matter how one looks at it, and I'm not sure I'd be able to tell the difference anyway at that point. That said, the other one is actually quite quiet, even up close. So maybe there's something there to try out in the recent future. I'm just enjoying my system so much right now I'd like to get a grasp of what's going on SQ-wise and put it to memeory as much as possible before making comparisons. I really appreciate your input on this particular thread! 

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I have two Topaz units, a 1KW and a 2.4KW. The 1KW unit in my previous listening room hummed fairly significantly, I had to devise a method of dampening sound without it overheating. The exact same transformer is used in my lab and doesn't make any noise at all. This MIGHT be due to the fact that the new house is three houses away from the substation and has very clean power.

 

I have the 2.4KW unit in the utility room right below the main panel, feeding the listening room. Again it does not make any noise at all.

 

John S.

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I have 3 Topaz units and all of them generated a bunch of heat and buzzing in my home.  When I switched them to balanced power config, maybe 95% of the heat and the buzz went away (cool and quiet as a cucumber).  

 

Note that not all electrical items (lamps etc) play nice with balanced power, although all my audio equipment (to date) has.  If you're not sure what you're doing, don't experiment, and if you do know what you're doing, make sure you keep civilians in the house from accidentally plugging something into the units that they shouldn't.

 

 

ATT Fiber -> EdgeRouter X SFP -> Sonore opticalModule -> Taiko Audio Extreme -> Chord DAVE -> Voxativ 9.87 speakers w/ 4D drivers

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Interesting. Odd that both my Topaz units are located in the same basement utility room, right next to each other and one hums, one doesn't. Neither one is even remotely hot, and neither presents a difficult load at all.

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  • 2 weeks later...

"So the chain is now Wall outlet -> UPS -> ISO transformer -> Equitech balanced transformer -> Audio loads. There are protective devices, such as a thermal overload, GFCI, over and undervoltage monitors in case the UPS has some kind of weird meltdown. As funds permit, I should connect the computers and IT gear to another UPS."

 

 @One and a half, this was quoted by you on about page 20 of the thread. I'm certain you've changed things a bit from 5 years ago, but are you recommending that the Topaz (with the audio/networking components on a strip from the Topaz) is plugged into a correctly sized UPS, and the UPS is from the wall? Or would you plug everything into the UPS, then the UPS into the Topaz with the Topaz coming directly from the wall? I have read these exact conflicting arrangements on a few forums/threads.

 

One last question: If one has something other than audio-related equipment (like a well or sump pump, for instance) that has to be plugged into the same 20a receptacle as the Topaz or UPS (depending on your recommendation from above), should it be plugged into the UPS, into the power strip with the audio-related components (PSUs, etc) or on its own (either into the receptacle at the wall or possibly its own IT or UPS)? I have always wondered if by stating 'all things into the same power strip' also means non-audio-related plugs.

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On 3/25/2021 at 12:45 AM, jsawyer09 said:

"So the chain is now Wall outlet -> UPS -> ISO transformer -> Equitech balanced transformer -> Audio loads. There are protective devices, such as a thermal overload, GFCI, over and undervoltage monitors in case the UPS has some kind of weird meltdown. As funds permit, I should connect the computers and IT gear to another UPS."

 

 @One and a half, this was quoted by you on about page 20 of the thread. I'm certain you've changed things a bit from 5 years ago, but are you recommending that the Topaz (with the audio/networking components on a strip from the Topaz) is plugged into a correctly sized UPS, and the UPS is from the wall? Or would you plug everything into the UPS, then the UPS into the Topaz with the Topaz coming directly from the wall? I have read these exact conflicting arrangements on a few forums/threads.

 

One last question: If one has something other than audio-related equipment (like a well or sump pump, for instance) that has to be plugged into the same 20a receptacle as the Topaz or UPS (depending on your recommendation from above), should it be plugged into the UPS, into the power strip with the audio-related components (PSUs, etc) or on its own (either into the receptacle at the wall or possibly its own IT or UPS)? I have always wondered if by stating 'all things into the same power strip' also means non-audio-related plugs.

The online UPS blew up and was glad it was gone. It chewed a lot of power with best efficiency at 80%. Since then, research revealed UPS emit common mode noise and a solution to that is to use an isolation transformer on the output. 

 

The sump pump works only on demand, in case of heavy rain will be on for long periods. 

If that's the case interference won't be that bad, it's the stopping and starting that will cause the audio system some grief.

 

For the pump, add an EMC filter plus an RC network / suppressor across the line and neutral. That will stop the audible clicks when the pump stops and starts. If you have an unused HT type power conditioner, use this for the pump, will also work well. I use an old Monster conditioner on the printer and it can take a laser,  so a pump will be OK. They claim to have high power, so why not put it to the test.

 

The Topaz can take care of the rest when plugged into the same outlet as the pump . Plug all the audio gear in the output of the Topaz. 

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38 minutes ago, One and a half said:

Since then, research revealed UPS emit common mode noise and a solution to that is to use an isolation transformer on the output. 

Thank you for your solutions! I do happen to have an older Monster HT conditioner. I also have a PowerVar ABC1200-11. However, concerning the above, if the Topaz is plugged into the UPS into one of the conditioning outlets, wouldn't that be negating the common mode noise? I figured the last part 'put the IT on the output' means just that, so is what I have done to mitigate the common mode noise the UPS emits. 

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1 hour ago, One and a half said:

Since then, research revealed UPS emit common mode noise and a solution to that is to use an isolation transformer on the output. 

Do you have a link handy? 

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8 hours ago, jsawyer09 said:

Thank you for your solutions! I do happen to have an older Monster HT conditioner. I also have a PowerVar ABC1200-11. However, concerning the above, if the Topaz is plugged into the UPS into one of the conditioning outlets, wouldn't that be negating the common mode noise? I figured the last part 'put the IT on the output' means just that, so is what I have done to mitigate the common mode noise the UPS emits. 

I’m not advocating a UPS for audio equipment online or offline, sine wave or anything in between. They cause distortion on the AC side and on the output contain common mode noise and the distortion is no better than AC mains from the street.

 

Best use a Topaz as is.

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Just wanted to say thanks, @One and a half. This is more or less where I started, so everything has come full-circle. It's just I read a lot online about how people were using a UPS with the Topaz, so thought I'd do some experimentation. I already had one, so figured, why not? However, your suggestion to put the pump/alarm on a Monster unit (in my case, it's a Panamax M5400, or the UPS now for that matter) was a good one. Initially I just had it plugged in to the extra receptacle the Topaz resided. So now it's:

 

20a Wall Receptacle #1 > Topaz > Tripp-Lite—Teddy Pardo 15/2 on Google Nest Router; Paul Hynes SR4 on EE8 Switch

20a Wall Receptacle #2 > Panamax (or UPS) > Septronics Pump/Alarm 

 

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