AC Polarity and the reduction of noise and hum

LL21 said:

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.

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microstrip said:

Ron,

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

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andromedaaudio said:

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.

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LL21 said:

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!

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amirm said:

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....

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amirm said:

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.

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DaveC said:

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...

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DaveC said:

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.

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LL21 said:

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

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LL21 said:

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.

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ddk said:

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

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ddk said:

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

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DaveC said:

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!

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microstrip said:

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!

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Amir said:

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

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microstrip said:

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.

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Amir said:

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.

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