[andyr]

A few years ago I read this 1997 article:
http://boundforsound.com/tweak.htm

Ever since then, I have believed that orienting the primary of your power transformer with respect to 'L' & 'N' in your mains feed was a prerequisite to getting the best sound out of your AKSA kit and so I have built my kit with DPDT mains switches.    (But, Kyrill, you really need to buy a "socket orienting gizmo" first, to figure out how your sockets are connected!  )

Now you may or may not agree with the theory that correct mains orientation leads to better sound ... but it's quite easy to test this out when you have DPDT mains switches!!  My previous AKSA N+s weren't in fact all wired up "correctly" and I didn't have DPDT mains switches but, as I am currently in the middle of upgrading my 6 AKSA N+ monoblocks to LF status, this time around I have taken the trouble to correctly orient the transformers.   

When I've finished, a few Melbourne LF owners will be able to come round and listen ... and put the theory to the test - ie. whether the better sound will be delivered by having all 4 mains switches down (lowest voltage reading) ... or up!    (4 mains switches being for XO, bass amp, mid amp and ribbon amp.)

However, I'm moved to write this because, in my experiments, I've discovered that the voltage reading is affected by the orientation of the secondaries, too!    Please note, though, that I am using the latest version of Hugh's LF/Soraya power supplies which has two diode bridges - one for '+' and one for '-'! 

So, if you connect the secondaries one way round you get one voltage reading and if you connect them the other way you get a slightly different reading.  Whether the orientation of the secondaries is really material ... I have no idea!    But if the theory espoused in the article is correct, the lowest voltage gives the best sound - so that is how I have arranged it! 
NB: To do this experiment, you need to employ female spade connectors for your PS spades, not solder the wires directly! 

Regards,

Andy

[kyrill]

good evening  eternal seeker for best sound
As  this in box electronic universe we call amp is soooo complex
i would/t be surprised that every little circuit has it s own preference
to sound best with a particular orientation,
so not following the theoretical ideal that all link in the chains
prefer the same orientation

If so, with x links in the chain ( SB3, Dac, burson audio buffer, preamp, amp)
you have to try out x² combinations to find the best sounding one
Poor Jens and others who possesses active 3way systems they have to try out with 4 links 48 combinations

4 links 2 orientations ( 1.2) only primaries
A1 B1 C1  D1        A2 B1 C1 D1
A1 B1 C2  D1        A2 B1 C2 D1
A1 B2 C1  D1        A2 B2 C1 D1
A1 B2 C2  D1        A2 B2 C2 D1
A1 B1 C1  D2        A2 B1 C1 D2
A1 B1 C2  D2        A2 B1 C2 D2
A1 B2 C1  D2        A2 B2 C1 D2
A1 B2 C2  D2        A2 B2 C2 D2

i think i would not have the patience and the memory to find out which combi sounds best

with my NAD video receiver all links  in one enclosure, at least one IEC outlet there is a discernible difference
and i prefer one orientation.

BTW here is ehh.. more about the subject http://www.audiocircle.com/index.php?topic=16787.0

[andyr]

good evening  eternal seeker for best sound

i would/t be surprised that every little circuit has it s own preference
to sound best with a particular orientation,
so not following the theoretical ideal that all link in the chains
prefer the same orientation

It may be that you are right, Kyrill (and that each circuit will have a different preferred orientation) ... but I myself don't believe so.  So in my active system, I have made sure phono stage and GK-1 are correctly oriented (ie. "correct" as per the article) and soon I will be in a position to hear how the amps sound with 4 power switches "down" vs. "up".

So it's not necessary to get tangled up in a million combinations! 

Regards,

Andy

[AKSA]

Hi Andy,

The effect you notice, I believe, is capacitive coupling across the windings of the trafo.  It's a very real issue and reflects the build structure of the transformer, where start and finish of the windings are at different points on the core.

If I may quote Alan Oldale, a very clever NZ technician friend,

If the active is connected to the layer adjacent to the secondary then coupling is at maximum. If it is connected to the part if the winding nearest the chassis then it will be reduced and there will be less RF floating arround, bypassed to the chassis instead.

The issue is in fact RF coming in off the antenna which is the mains grid.  This RF intermodulates with the audio passing through the amp, causing audible beat phenomena which add hum, noise, and generally make the music less clear.

RF can come through the speaker leads - we have both seen this happens with speakers with very large voice coils like your Maggies - but it can also come through the mains, into the amp via star earth and rails, particularly if the rail bypassing is not adequate.

My thanks to Alan for his advice.

Cheers,

Hugh

[kyrill]

hi Hugh

yr answer suggest each part of the chain with an AC transformer will then have its "preference"
depending how the transformer internally is connected. But do for instance toroid transformer manufacturers
color code the 2 ac wires coming out of the primaries so you should connect them only in one
right way to AC??
Such instructions are missing and the wires are indistinguishable (white) when i buy them here in Holland. also non toroid transformers ( over here) dont instruct a "right" way to connect them to AC

So i wonder if manufacturers actually give this "internal" attention. Maybe some high end brands?

[andyr]

So i wonder if manufacturers actually give this "internal" attention. Maybe some high end brands?

I would suggest, Kyrill that there is not a mfr on the planet that actually tests this out - and orients their traffos "correctly".  After all ... many people (most people?  ) don't believe in the theory - that measuring the lower of the two voltages (as described in the Bound for Sound article which I referenced) delivers better sound!    And even that article didn't talk about the orientation of the secondaries ... because that is something which only us DIYers can do! 

As I said, I believe in the theory but I haven't actually been able to test it out.  Soon, though, I will have a setup where the sonic impact of 'switch down' vs. 'switch up' can be easily compared!!   

Regards,

Andy

Regards,

Andy

[kyrill]

i have bought multiple isolation transformers ( all of the non toroid type) of twice the wattage of the component it is attached to, with the two secondary windings connected to each others to transform the transformer aa into a balanced one.  So the issue becomes obsolete. I also put a Felix or felicia between balanced trafo and the iec AC input of the component. it made a major impact. i hear much more micro details and transparency between the sounds

Except my Home theater NAD receiver, still must do

[AKSA]

Kyrill,

I would agree with Andy.  When 99% of customers buy a transformer they are not in the least interested in the leakage capacitance and inductance.  It's off the radar.  There are instances where these measurements are important, but they are generally confined to audio output transformers and some transformers built for very high frequency use in industry.

I may be wrong, but I don't believe that the differences Andy has noted are particularly important for the sound.  The currents found in the output stages of audio amplifiers are truly large;  up to 10 amps, and the leakages of these transformers trivially low, particularly when set up with viable earthing systems.  Where leakage and earthing is truly significant is in terms of hum and noise, and its mostly balanced out with properly designed bipolar supplies.  Of course, noise does affect resolution directly by masking, so that would be a legitimate argument, but a quiet supply as used on the Lifeforce and Soraya is the cat's meow in this regard.

I hope this helps to put it in perspective.  This is tricky to achieve in any nth degree technology!   

Hugh