Discussion of AC mains isolation transformers

[One and a half]

1 minute ago, frederick184 said:

I just picked up a Topaz 91095-32 500 Va isolation transformer on eBay.  My system is split into two parts.  My Comcast modem, wireless router, dedicated music PC, NAS, fiber switch and FMC's are all in an upstairs room.  The FMC's are connected to the NAS and the wireless router, and the PC has a fiber NIC connected to the fiber switch.  All devices are plugged into a single Wiremold power strip with no filtering.

 

Downstairs there is another wireless router connected to the master one upstairs in a mesh network.  An Ethernet cable connects to my Ultra Rendu powered by LPS-1.  This in turn is plugged either into my Oppo UDP-205 players USB DAC by a Lush cable or to my LH Labs Infinity X DAC.  The signal goes from there to my Parasound A21 amp and then to my Magnepan MG 3.7 speakers.  All devices are plugged into an Audience AR6-PDC with no filtering.  This part of the system is fed by a dedicated 20 amp circuit.  The upstairs part of the system is not.

 

I intended to buy an isolation transformer for both, but I'm wondering in the meantime which part of the system would benefit from it most?

 

Colin

The Topaz is primarily a protection device. Since it's possible to hear clicks and plops, the audio system has priority for the Topaz to be fitted. 

[One and a half]

28 minutes ago, spacexpert said:

Just been checking out other IT options in the hope of finding one that will run cooler.

I note that some have a sticker on the black part that reads "caution hot surface, avoid contact" 

 

So I guess these things can get hot enough to warn you not to touch.  That's pretty hot.

 

It wouldn't by chance be a combination of 240V + high capacitance .0005 that is a factor?

Regardless I guess it should run cool with low load...    

Hmm. How hot is hot? The Topaz can work from 0-50C ambient temperature.  It could have Class F Winding insulation, which can handle 130 C. @zilch0md quoted 40.6C at an ambient of 25C  his transformer wasn't fully loaded....that's 15.6 C above ambient. Perhaps double that for full load, that 80C case temperature, still OK for Class F. 80 C is really hot, you don't get even near it!

 

Class A insulation has a recommended temperature limit of 105 Degrees C or 221 Degrees F. 

Class B goes to 130 Degrees C or 226 Degrees F, 

Class F to 155 Degrees C or 311 Degrees F, and 

Class H to 180 Degrees C or 356 Degrees F.

 

The 0.00005 pf is an ability to block high frequencies, the lower the pf, the higher the opposition to that noise creeping in.

 

I hope to publish some figures on the 1000VA unit, surface temperature of the laminations and loading this weekend.

[spacexpert]

4 minutes ago, One and a half said:

quoted 40.6C at an ambient of 25C

Mine would be easily 60+ unloaded.  Perhaps not a problem out in the open, but to conceal the hum in a small room.  Not going to put this thing in a box, too risky.   

[d_elm]

1 hour ago, frederick184 said:

I just picked up a Topaz 91095-32 500 Va isolation transformer on eBay.  My system is split into two parts.  My Comcast modem, wireless router, dedicated music PC, NAS, fiber switch and FMC's are all in an upstairs room.  The FMC's are connected to the NAS and the wireless router, and the PC has a fiber NIC connected to the fiber switch.  All devices are plugged into a single Wiremold power strip with no filtering.

 

Downstairs there is another wireless router connected to the master one upstairs in a mesh network.  An Ethernet cable connects to my Ultra Rendu powered by LPS-1.  This in turn is plugged either into my Oppo UDP-205 players USB DAC by a Lush cable or to my LH Labs Infinity X DAC.  The signal goes from there to my Parasound A21 amp and then to my Magnepan MG 3.7 speakers.  All devices are plugged into an Audience AR6-PDC with no filtering.  This part of the system is fed by a dedicated 20 amp circuit.  The upstairs part of the system is not.

 

I intended to buy an isolation transformer for both, but I'm wondering in the meantime which part of the system would benefit from it most?

 

Colin

Do you have to run data over wireless ?  Cannot have a wire or fibre between the two levels ?  

[frederick184]

3 hours ago, d_elm said:

Do you have to run data over wireless ?  Cannot have a wire or fibre between the two levels ?  

Unfortunately not.  I live in an old house and it isn't easy to run wires between floors.  I have two Portal routers, one on each floor.

 

Colin

[Cornan]

5 hours ago, frederick184 said:

I just picked up a Topaz 91095-32 500 Va isolation transformer on eBay.  My system is split into two parts.  My Comcast modem, wireless router, dedicated music PC, NAS, fiber switch and FMC's are all in an upstairs room.  The FMC's are connected to the NAS and the wireless router, and the PC has a fiber NIC connected to the fiber switch.  All devices are plugged into a single Wiremold power strip with no filtering.

 

Downstairs there is another wireless router connected to the master one upstairs in a mesh network.  An Ethernet cable connects to my Ultra Rendu powered by LPS-1.  This in turn is plugged either into my Oppo UDP-205 players USB DAC by a Lush cable or to my LH Labs Infinity X DAC.  The signal goes from there to my Parasound A21 amp and then to my Magnepan MG 3.7 speakers.  All devices are plugged into an Audience AR6-PDC with no filtering.  This part of the system is fed by a dedicated 20 amp circuit.  The upstairs part of the system is not.

 

I intended to buy an isolation transformer for both, but I'm wondering in the meantime which part of the system would benefit from it most?

 

Colin

 

Why not try at both locations and find out what makes the best improvement?

Anyway, if you are listening to cloud content (Tidal, Quboz etc) I would say that you will gain most upstairs. With local content you probably want to start downstairs, but since your NAS and PC is upstairs it is a close call depending on how the NAS and PC is powered.

Nothing wrong with wireless, but exept flawless strong wireless signal you want a wireless adapter/bridge into a network switch close to the setup downstairs IMO.

[Cornan]

6 hours ago, spacexpert said:

Just been checking out other IT options in the hope of finding one that will run cooler.

I note that some have a sticker on the black part that reads "caution hot surface, avoid contact" 

 

So I guess these things can get hot enough to warn you not to touch.  That's pretty hot.

 

It wouldn't by chance be a combination of 240V + high capacitance .0005 that is a factor?

Regardless I guess it should run cool with low load...    

 

Any transformer can temporarily be quite warm and even close to burning hot. It is designed to handle high temperatures as well. IME a humming transformer gets hotter than a silent one. Probably because it works harder. If there is no load the transformer should have an easy job unless you have extreme amounts of DC offset which is highly unlikely.

[spacexpert]

23 minutes ago, Cornan said:

 

Any transformer can temporarily be quite warm and even close to burning hot. It is designed to handle high temperatures as well. IME a humming transformer gets hotter than a silent one. Probably because it works harder. If there is no load the transformer should have an easy job unless you have extreme amounts of DC offset which is highly unlikely.

I've noticed that at certain times of the day my amp hums quite a bit, then other times it is quiet.  Is that related to DC offset?

[Ralf11]

about the same time each day?  or...

[spacexpert]

1 minute ago, Ralf11 said:

about the same time each day?  or...

From memory I can't be sure, I never thought to document the times.  What would it mean if it was a pattern as opposed to random?  

[Cornan]

42 minutes ago, spacexpert said:

I've noticed that at certain times of the day my amp hums quite a bit, then other times it is quiet.  Is that related to DC offset?

 

Not impossible! Here is a good explanation about DC offset http://sound.whsites.net/articles/xfmr-dc.htm

 

This is also interesting to read regarding DC bias, especially to understand why ac mains DC blockers sometimes are more effective pre a IT in certain countries:

 

"The electrical grid, which is normally three-phase AC, can be severely disrupted by the presence of a large DC bias. This is caused by strong solar flares hitting the Earth's atmosphere, which in turn creates strong electromagnetic fields. This induces voltages in long-distance electrical lines, which can be strong enough to arc across transformers. (Even pipelines, such as the mostly above-ground Alaska Pipeline, are prone to this, and must be tied to electrical groundwith zinc sacrificial anodes.) This is a rare but serious problem, mostly for far northern locations like Canada and Scandinavia, where a strong aurora borealiswill cover much lower latitudes than normal during such a situation. Space weather forecasts are used to predict when these geomagnetic storm events might occur. High-voltage direct current systems have their own control gear at conversion stations and can adapt somewhat better to such conditions. However, large and often widely fluctuating voltages can still cause problems like harmonics."

[spacexpert]

Now I have solar flare problems. 

Thank you Cornan.  I will read up on DC offset.  

But first I need a cup of tea and a sit down.

?

[Cornan]

Just now, spacexpert said:

Now I have solar flare problems. 

Thank you Cornan.  I will read up on DC offset.  

But first I need a cup of tea and a sit down.

?

 

Make it a strong cup of coffee! ?

[One and a half]

Temperature and loading results 1000VA 0.001pf 91001-21 transformer.

 

Ambient : 22.7C 

Idle :

Consists of energising 1000VA Equitech transformer and MPD-3 DAC which is on 24/7 . Primary current 0.47A, 239V input 112.33VA.

Lamination temperature : 37.5 C

 

On Load : Ssytem 1 and System 2 on, low level music, maybe 1 Watt output

1.43A, 239V, 342VA input. 

 

Left on load for an hour, Lamination temperature : 38.3 C, Ambient Temperature 24.4 C

 

Temperature readings with a contact K type thermocouple. 

[spacexpert]

19 minutes ago, One and a half said:

Temperature and loading results 1000VA 0.001pf 91001-21 transformer.

 

Ambient : 22.7C 

Idle :

Consists of energising 1000VA Equitech transformer and MPD-3 DAC which is on 24/7 . Primary current 0.47A, 239V input 112.33VA.

Lamination temperature : 37.5 C

 

On Load : Ssytem 1 and System 2 on, low level music, maybe 1 Watt output

1.43A, 239V, 342VA input. 

 

Left on load for an hour, Lamination temperature : 38.3 C, Ambient Temperature 24.4 C

 

Temperature readings with a contact K type thermocouple. 

Nice, that's more the temperature I'm looking for.  Very useful to see measured temps.  Thank you!  

[One and a half]

4 hours ago, spacexpert said:

I've noticed that at certain times of the day my amp hums quite a bit, then other times it is quiet.  Is that related to DC offset?

Does the hum change pitch?

[spacexpert]

Just now, One and a half said:

Does the hum change pitch?

No, it is a steady pitch coming from the toroidal.  Interestingly, when it hums, if I put my ear to my speakers I hear the same sound through them.  It might last for 30 minutes then die down for several hours.  

I don't hear it from my listening position, so it doesn't bother me.

 

In the mean time my best offer was accepted for another Topaz.  Same spec as the last one.  So... ?    

[One and a half]

1 minute ago, spacexpert said:

No, it is a steady pitch coming from the toroidal.  Interestingly, when it hums, if I put my ear to my speakers I hear the same sound through them.  It might last for 30 minutes then die down for several hours.  

I don't hear it from my listening position, so it doesn't bother me.

 

In the mean time my best offer was accepted for another Topaz.  Same spec as the last one.  So... ?    

Lots of Luck!

[spacexpert]

Just now, One and a half said:

Lots of Luck!

I'm sweating bullets.  I'll keep you updated!

[One and a half]

1 hour ago, spacexpert said:

No, it is a steady pitch coming from the toroidal.  Interestingly, when it hums, if I put my ear to my speakers I hear the same sound through them.  It might last for 30 minutes then die down for several hours.  

I don't hear it from my listening position, so it doesn't bother me.

 

 

There's a ground loop there trying to break through..... quite possibly a loose connector in the signal chain somewhere. Any clicks?

[spacexpert]

16 minutes ago, One and a half said:

 

There's a ground loop there trying to break through..... quite possibly a loose connector in the signal chain somewhere. Any clicks?

No clicks, other than AC line noise, pops and crackles etc.  It's a low level dirty hum, sounds exactly like a ground loop but really quiet.

I once touched a ground wire to the negative terminal of one of my speakers and it went away, didn't work on the other speaker though.  

Being a non-common ground amp, I am not comfortable with trying to ground the negative terminals on both my speakers, so I gave that idea a miss.  Both my subs are grounded, my interconnects need to be grounded as well (Chord DAC running off batteries) My previous DAC that was mains powered didn't need grounding wires hooked up to the interconnect plugs. 

So I've got a lot of grounding wires.  I think it would be an issue with sensitive speakers, thankfully I'm down in the 84dBA @ 1m range.

Another weird thing about the Lavardin amp... it likes the hot wire on the wrong side of the IEC, so I have to make my own power cords for it.  Seems strange, but I do what they say. ?  

[One and a half]

1 minute ago, spacexpert said:

 

Another weird thing about the Lavardin amp... it likes the hot wire on the wrong side of the IEC, so I have to make my own power cords for it.  Seems strange, but I do what they say. ?  

With the wiring of the Topaz in balanced mode, there's no wrong side, both conductors at the amp's plug are live to earth. 

[spacexpert]

Just now, One and a half said:

With the wiring of the Topaz in balanced mode, there's no wrong side, both conductors at the amp's plug are live to earth. 

I will confess to being a bit ignorant about balanced mode.  Is the 240V balanced by default, or does that require some funky rewiring?

[Cornan]

12 minutes ago, spacexpert said:

Another weird thing about the Lavardin amp... it likes the hot wire on the wrong side of the IEC, so I have to make my own power cords for it.  Seems strange, but I do what they say. ?

 

A tip is to get yourself a Oehlbach Phaser http://www.oehlbach.com/en/power/phaser, so you can find out the correct phase on all of your equipment. It can make a great improvement. 

 

You´ll also need a no contact phase pen to find out the correct phase in the ac mains wall inlet.

 

[spacexpert]

4 minutes ago, Cornan said:

 

A tip is to get yourself a Oehlbach Phaser http://www.oehlbach.com/en/power/phaser, so you can find out the correct phase on all of your equipment. It can make a great improvement. 

 

You´ll also need a no contact phase pen to find out the correct phase in the ac mains wall inlet.

 

Never knew this existed, thanks for the link.  I didn't know phase mattered until Lavardin stated that their amp sounds much better with correct phase.

When I first tried a reverse phase power cord it sounded less bright and a little more laid back.  I kept it that way and assumed it to be correct.