AC Polarity and the reduction of noise and hum

[amirm]

Amir,

If we use something like an Interocitor from Steve McCormack in between the SE preamp and the Balanced amp...does this work in your opinion? I have heard nothing but great things about it from Gary Koh and Microstrip.

I just took a look at its specs and yes, it is a transformer conversion of single-ended to balanced. The only drawback of transformers in this application is any non-linearity they may have. High-performance ones like that likely are very good in that regard.

 

[amirm]

Ron,

The topic will stay clear while you do not mix the technical aspects with preference, and particularly how we should check preference ...

Like to see a show of hands of who has a preference for mixing mains related frequencies into their audio signal. Anyone?

Because if you do, it would be trivial to heap as much as you like in there! Talk about anti-audiophile....

 

[andromedaaudio]

So then the situation could arise , if THD isnt a very reliable check .
That a very well designed/ accurate /natural sounding pre / power ampscombo , however single ended design and connected with rca cables , sound better then a balanced pre/power combination connected with balanced cables.

 

[amirm]

So then the situation could arise , if THD isnt a very reliable check .
That a very well designed/ accurate /natural sounding pre / power ampscombo , however single ended design and connected with rca cables , sound better then a balanced pre/power combination connected with balanced cables.

Sure.

 

[DaveC]

Amir,

If we use something like an Interocitor from Steve McCormack in between the SE preamp and the Balanced amp...does this work in your opinion? I have heard nothing but great things about it from Gary Koh and Microstrip.

In our case, i do hear a little noise which i suspect is from the 'grid' of the house...but tube noise is greater...and i still need to stand next to the tweeter with my ear actually perpendicular to hear this noise when the entire room has no lights on, no music playing, etc. Nevertheless, as an audiophile, i have to ask!

Not sure what the Interocitor is, but I built my Hypex nCore NC500 balanced mono amps (for the active woofer in my speakers or my full-range reference speakers) using a Jensen input trafo which converts SE > Bal and also galvanically isolates the input. It also has XLR in of course. My 32/384 DSP unit also has the same kind of trafo-based SE inputs, it also has XLR out to the amps, which is what I use if I'm using the amps for the active woofer section.

Jensen sells the trafos in their own enclosures as well, IsoMax I think...

The Hypex amps are great in terms of woofer control but short on mid-high frequency refinement using the OEM input board... I'll be building a prototype with tube input section instead of opamp eventually. Looking into a suitable trafo to mate the tube output to the NC500 inputs...

 

[DaveC]

Like to see a show of hands of who has a preference for mixing mains related frequencies into their audio signal. Anyone?

Because if you do, it would be trivial to heap as much as you like in there! Talk about anti-audiophile....

Why do you carry on with this bullshit? This is quite obviously trolling and meant to be inflammatory. You're not admin and TOU applies to you too now. If you want to martyr yourself feel free I guess, but don't complain about it later as it's pretty clear it would be the result of TOU violations and not simply that people don't like your opinions.

 

[LL21]

I just took a look at its specs and yes, it is a transformer conversion of single-ended to balanced. The only drawback of transformers in this application is any non-linearity they may have. High-performance ones like that likely are very good in that regard.

Thanks. The one 'problem' of course is another set of ICs is required. Nevertheless, will keep that on the list of things to try over time.

 

[LL21]

Not sure what the Interocitor is, but I built my Hypex nCore NC500 balanced mono amps (for the active woofer in my speakers or my full-range reference speakers) using a Jensen input trafo which converts SE > Bal and also galvanically isolates the input. It also has XLR in of course. My 32/384 DSP unit also has the same kind of trafo-based SE inputs, it also has XLR out to the amps, which is what I use if I'm using the amps for the active woofer section.

Jensen sells the trafos in their own enclosures as well, IsoMax I think...

The Hypex amps are great in terms of woofer control but short on mid-high frequency refinement using the OEM input board... I'll be building a prototype with tube input section instead of opamp eventually. Looking into a suitable trafo to mate the tube output to the NC500 inputs...

Thanks...that is very similar to Interocitor and i have heard about it as well. Good to know.

 

[Steve Williams]

Why do you carry on with this bullshit? This is quite obviously trolling and meant to be inflammatory. You're not admin and TOU applies to you too now. If you want to martyr yourself feel free I guess, but don't complain about it later as it's pretty clear it would be the result of TOU violations and not simply that people don't like your opinions.

we are indeed following this thread closely Dave

It's up to individuals if you want to feed the troll

Once again I want to remind everyone about the "ignore" button if the trolls get to you

 

[ddk]

Thanks...that is very similar to Interocitor and i have heard about it as well. Good to know.

Hi Lloyd,

We've used this type of transformer many times in HT installations to eliminate hum & ground loops, not to convert to balanced. The Jensen Iso Max units are my own favorites, high quality and very fair pricing, no audiophile gouging! But I'll never use them for high end music reproduction, they do have side affects. In Dave C's case he's using them with his subs which is fine, nothing is really compromised the way he's using them.

david

 

[DaveC]

Thanks. The one 'problem' of course is another set of ICs is required. Nevertheless, will keep that on the list of things to try over time.

Yes, I don't like the separate chassis and requirements to have another set of ICs... the trafos are very small, probably easy to fit inside many components. They are relatively expensive though, so most mfg'ers stay away but if you want to drive a balanced amp with a SE tube preamp it seems like the best way to do it to me, and also eliminates the possibility of ground noise issues. They can be paralleled with XLR inputs in a couple different ways, since the trafos are very transparent right now I have the XLR and RCA ins run in parallel into the trafo primaries with no switch, you just can't have an RCA and XLR cable plugged in at the same time. A switch would allow the XLR in to bypass the trafo, but now there's a switch. Most class D amps are balanced, it doesn't matter to me so much as I mostly value their amazing grip on woofers. The NC500s are FANTASTIC for active bass duties!

 

[DaveC]

Hi Lloyd,

We've used this type of transformer many times in HT installations to eliminate hum & ground loops, not to convert to balanced. The Jensen Iso Max units are my own favorites, high quality and very fair pricing, no audiophile gouging! But I'll never use them for high end music reproduction, they do have side affects. In Dave C's case he's using them with his subs which is fine, nothing is really compromised the way he's using them.

david

Especially good for subs and active bass, as people regularly have active speakers or subs plugged into a different circuit vs the rest of their system. It's by far the most common hum related issue I see...

 

[LL21]

Hi Lloyd,

We've used this type of transformer many times in HT installations to eliminate hum & ground loops, not to convert to balanced. The Jensen Iso Max units are my own favorites, high quality and very fair pricing, no audiophile gouging! But I'll never use them for high end music reproduction, they do have side affects. In Dave C's case he's using them with his subs which is fine, nothing is really compromised the way he's using them.

david

good to know...i spoke with Gryphon about it, and while they did say i should reterminate the single ended cables (and not use the Neutrik adaptors which come with the amp for temporary use)...they did not seem bothered by SE inputs from the preamp based on our discussions.

 

[LL21]

Yes, I don't like the separate chassis and requirements to have another set of ICs... the trafos are very small, probably easy to fit inside many components. They are relatively expensive though, so most mfg'ers stay away but if you want to drive a balanced amp with a SE tube preamp it seems like the best way to do it to me, and also eliminates the possibility of ground noise issues. They can be paralleled with XLR inputs in a couple different ways, since the trafos are very transparent right now I have the XLR and RCA ins run in parallel into the trafo primaries with no switch, you just can't have an RCA and XLR cable plugged in at the same time. A switch would allow the XLR in to bypass the trafo, but now there's a switch. Most class D amps are balanced, it doesn't matter to me so much as I mostly value their amazing grip on woofers. The NC500s are FANTASTIC for active bass duties!

thanks! good to know and will keep this in mind.

 

[Amir]

The technical explanation is however much simpler than what referred in your link - the correct position creates less leakage current through the ground wire, reducing ground noise. Just Ohm's law - the VOM behaves like an high value resistor!

No , less leakage current does not give us better sound
For example all TAD D600/C600/M700 correct polarity has higher chassis voltage (more leakage current) and the sound is far better when AC polarity is correct.
Chassis voltage of TAD D600 or C600 is 160v in correct polarity and it is 40v in invert AC polarity.
These numbers are for 230v versions of TAD.

Chassis voltage of TAD M700 is 105v in correct polarity and it is 50v in invert AC polarity.

another example is Vitus SIA-025 (230v version).
The vitus chassis voltage is 120v when AC pokarity is correct and it is 80v when the AC polarity is invert.

The sound of both TAD and Vitus is so much better when the AC polarity is correct

 

[microstrip]

No , less leakage current does not give us better sound
For example all TAD D600/C600/M700 correct polarity has higher chassis voltage (more leakage current) and the sound is far better when AC polarity is correct.
Chassis voltage of TAD D600 or C600 is 140v in correct polarity and it is 40v in invert AC polarity.
These numbers are for 230v versions of TAD.

Chassis voltage of TAD M700 is 105v in correct polarity and it is 50v in invert AC polarity.

another example is Vitus SIA-025 (230v version).
The vitus chassis voltage is 120v when AC pokarity is correct and it is 60v when the AC polarity is invert.

The sound of both TAD and Vitus is so much better when the AC polarity is correct

Well, I would say you prefer the sound in your system with higher ground noise! No problem with that.

Are you calling "correct polarity" the IEC conventional polarity? Many manufacturers do not take care of it and explicitly say there is no difference in orientation.

In this hobby one man's meat is another man's poison - surely in this case we should use our ears. I found my ears agree with the measurement, I am happy with that. To be true, I do not find a night and day difference with polarity and in casual short time listening of equipment I do not care about it, but my ground line is very good.

 

[Alrainbow]

The reason this topic is real is simple
windings of the transformers have a direction and this gets complex to understand
What I have found is the doc ripple of not in phase is additive if in phase it’s only what the difference is.
years ago Lampi made a sw box called a silk
It allowed you to reverse the polarity of each output receptacle
it does work
I made one but it’s not NEC compliant so in the USA it never took off.

 

[Amir]

Well, I would say you prefer the sound in your system with higher ground noise! No problem with that.

Are you calling "correct polarity" the IEC conventional polarity? Many manufacturers do not take care of it and explicitly say there is no difference in orientation.

In this hobby one man's meat is another man's poison - surely in this case we should use our ears. I found my ears agree with the measurement, I am happy with that. To be true, I do not find a night and day difference with polarity and in casual short time listening of equipment I do not care about it, but my ground line is very good.

Yes, Correct polarity in my pervoius text is the same standard IEC.
I am 100% sure you will prefer the sound of both Vitus and TAD when the chassis voltage is higher (correct Polarity). The difference is like day and night.
TAD does not connect chassis to earth and the you can sense 100v on the chassis of TAD when you touch it.

Clark Johnson has a book (the wood effect) , I do not find it but it is about polarity.

 

[adyc]

Yes, Correct polarity in my pervoius text is the same standard IEC.
I am 100% sure you will prefer the sound of both Vitus and TAD when the chassis voltage is higher (correct Polarity). The difference is like day and night.
TAD does not connect chassis to earth and the you can sense 100v on the chassis of TAD when you touch it.

Clark Johnson has a book (the wood effect) , I do not find it but it is about polarity.

Do I read it correctly? 100V on chassis? Won’t you get electrical shock by touching chassis ?

 

[Amir]

No, there is no shock.

All of TAD products (C600/D600/M700) are isolated from the wall Earth wire and I think their decision is very good.
Most of safety wall earth wires in the apartments are shared and are not good for sound quality except you have delicated low impedance earth for your audio system.


I am not expert but I think proper grounding (for maximum sound quality) is not dependent to having earth wire.
Earth wire is useful for safety if I am not mistaken.