[Lost81]

Hi guys,

I am collecting tips / ideas on optimizing a pair of AKSA 100W Nirvana monoblocks for bass duty in my set-up.
Each amplifier is responsible for a single, long-throw, vented, band-bypassed 8" woofer only, nothing else.

This is what I have so far:

"1.0uF Auricap for DC blocking. ...the original .47uF does limit LF a tad."

"Reservoir Power Capacitors (63V 4700uF x Qty4): Sprague.  Fantastic bass, moderate mid and slightly indistinct treble."

Anyone know the specific model of Sprague caps used?

Note: Anyone attempting to employ this post as confirmation / pseudo-evidence that the AKSA 100W Nirvana lacks bass, brands himself / herself as a moron and an ignoramus towards the concept of "specialization."    The aim of this post is to explore the possibilities in optimizing a particular pair of AKSAs for bass duty only in a bi-amped set-up, with no regard for trade-offs in treble or midrange (I am optimizing another pair of AKSA 100W Nirvanas for midrange / treble duty, with the consequent trade-off in bass).

Many thanks!



-Lost81

[andyr]

Hi, Lost81,

Yes, I use a pair of 100w monoblocks for my Maggie base panels in my 3-way active system.

These have 1uF blocking caps but I used a Relcap TRT here.

The filter caps you mention may well be great for base but I couldn't advise.  I would've liked to use BGs but couldn't afford them - so I used Nichicon KGs instead.  However, I also used a 47uF Solen as a bypass cap, for the 100watters only (but they're a bitch to solder in place as their leads are short).

Regards,

Andy

[kyrill]

oh you guys you really go sharp don't you?

I wasn't thinking of specialising the Aksa's for bass or treble in my triamp setup(at least not yet).
As we cannot listen to a single unit but only to the whole chain I noticed for my self what a HUGE difference it is (at least in Holland) to purify the current from the wall next to purifying the clock in yr cd speler or  C37 the arm of yr vinyl player (I have a Well Tempered turntable and arm, very happy with it)

Lost 81 have you reclocked yr cd player already? ( I cant remember if you did)
Andyr do you have already a balanced (mother) power supply?
I don't mean to be paternalistic.
 I really found out for myself (next to Herbies cdmat) what a big difference it makes in an already good system

[andyr]

.... Andyr do you have already a balanced (mother) power supply?...

Hi, Kyrill,

No, Kyrill, at present all I have wrt AC power is a short "ordinary" 20amp dedicated line from the breaker-box to my source components.  I used to have my AKSAs plugged into this as well but now I have them up the other end of the room, behind the speakers, so they are plugged into one of the other house circuits - this happens to be a 30 amp circuit as it supplies the pool pumps.

What do you mean by a "balanced" power supply?

Regards,

Andy

[kyrill]

I did not have one until I met the theory on the net and it convinced me. I, however was not "ready" to accept how big the difference was. The music was embedded in "silence" .But I had to silence the room first, which happened by "accident"at the same time . I used the soft big tiles what shops put normally under a new wall to wall carpet, actually under my movable "loose"carpet. I sticked it to the ceiling after spraying it white .

The theory read: " At this point a brief explanation of balanced power is probably appropriate.  In a normal unbalanced power line you have a hot conductor(120V to ground),  a neutral conductor(0V to ground) and the ground. This unbalanced configuration permits low level noise contamination to pass through the power line directly to your sensitive audio components.  In the Music Ring the 120V to ground is converted to two 60V to ground. These 60V signals are 180 degrees out of phase with one another. You still have 120V, 60hz available at the outlet receptacles but the noise has been cancelled out  by common mode rejection.

The Music Ring's effect on music is dramatic. If we could only make one recommendation to audiophiles it would be to listen to their current system with balanced power before considering another upgrade. "You haven't heard what your system is capable of until you have plugged it into a Music Ring."

This is an excerpt from http://www.bluecircle.com for their "music ring"
Another more cheaper approach is from  http://www.transcendentsound.com/power_supply.htm

So what's Balanced Power?
In the USA, electric power is delivered to homes in a "single-ended" fashion with two wires.  One wire, called the neutral, is always held at 0 volts.  There is no voltage on it.  The other wire, called the hot, carries all of the 120 volts AC.  Balanced power converts the single-ended power to a balanced power system with both wires now carrying 60 volts AC, each out of phase with each other.  The total voltage between them is then 120V.  The ground wire is held at 0 volts.

How does it remove power line noise?
Transformers only respond to voltage differences between their leads.  Power lines often have a type of noise called common mode noise which is present on both the neutral and hot wire.  The Balanced Power Supply contains a massive toroid transformer that reject much of this noise.

But what about noise on just the hot wire?
The output of the Balanced Power Supply contains heavy filtering to eliminate much of this noise.  Often times, audio equipment itself generates noise that gets fed back into the power line.  The noise is then free to invade other equipment.  Power amps with laminated power transformers can be the worst offenders.  The heavy filtering on the output can help to eliminate much of this noise.

What is a ground loop?
A ground loop occurs when different equipment grounds are at different voltages, causing noisy ground currents to flow between them.  The Balanced  Power Supply creates a new ground called a derived ground, that decouples equipment connected to it from these circulating ground currents in the rest of the house wiring.  It also provides one common ground reference for all the equipment connected to it.

How does it reduce radiated fields?
Because the power is delivered by two out of phase signals, the electric fields produced by each should largely cancel.  This reduces noise caused by radiated fields.  This is same principal used with twisted pair cable but in reverse.  Instead of rejecting noise, power carrying cables don't radiate noise in the first place.

How does if reduce interference between equipment?
Most modern electronic equipment uses switching regulators in their power supplies.  These devices can produce RF noise that can couple through the power cord to other equipment.  The balanced power supply provides a very low impedance to the connected equipment which shorts out this high frequency noise.  Some users have reported improvements in large screen video performance. "

In holland as in Australia we don't have balanced power out of the wall  
The difference is NOT subtle. If yr room is quiet people who will listen will be wildered. They think somehow that the purity of silence is somehow yr amp or speakers, but silence is a strange phenomenon. How can you hear it while listening to music? Still that is exactly what happens.

"Some users have reported improvements in large screen video performance."

I have a dedicated JVC D-ILA 1360x1024 projector. I use Ffdshow and ZoomPlayer as the dvd software player on the PC. Balanced power and filters clean up the image and sharpens it. The difference is again not subtle at all.

[andyr]

In a normal unbalanced power line you have a hot conductor (120V to ground), a neutral conductor (0V to ground) and the ground. This unbalanced configuration permits low level noise contamination to pass through the power line directly to your sensitive audio components. ...

Kyrill,

What you have said is true for the US.  I am in Oz (aka "God's own") where we have 240v mains like you do.  Also, I suspect our power is delivered differently to the US ... for instance, in the US they go on and on about reversing mains plugs and one way will a) sound better than the other and b) will result in a lower voltage reading between chassis and mains earth.  (This is easy to do in the US as their mains plugs are sometimes just two parallel blades ... easy to flip.)

I've tried testing this several times here in Oz - more difficult to do as we use a 3-pin mains plug, so you have to make up a short extension cord with the 'active' and 'neutral' wires crossed.

Because I have never been able to hear the difference reversing the mains phase, I suspect our power is generated in a more 'balanced" fashion than in the US.

Any EEs care to comment ... Ginger???

Regards,

Andy

[kyrill]

Balanced power or not in Australia has been discussed this year before on this forum. I tried search but too many entrees to spit thru. But the outcome I remember (if well remembered) was that also AUS has unbalanced pwr just like in Holland

[Gordy]

Kyrill,  Was that perhaps the OneAC conditioner thread?

[andyr]

Balanced power or not in Australia has been discussed this year before on this forum. I tried search but too many entrees to spit thru. But the outcome I remember (if well remembered) was that also AUS has unbalanced pwr just like in Holland

Kyrill,

Then surely it follows that you and I should be able to hear the difference - like people in the US -  when we "flip" active and neutral wires by deliberately wiring an AC plug wrongly or interposing a short extension cord (which has been "flipped") between the "normal" AC plug and the wall socket.

I have tried this and I cannot hear the difference ... have U ever tried it?  If not, I suggest you should remove your balanced power device and try it with your normal AC mains.

Regards,

Andy

[kyrill]

I found this on the internet from
http://www.energy.com.au/ea/earetail.nsf/AttachmentsByTitle/ES2/$FILE/es2.pdf

EnergyAustralia's Supply standards:
Supply voltage is the voltage existing at any time, from phase to neutral
or phase to phase, at the consumer’s terminals.
The nominal voltage for the low voltage network is 240 Volts, phase to
neutral, and 415 volts phase to phase.

240 volts over neutral to phase means unbalanced power

Andy

The difference i hear when reversing the leads is always subtle but  consistent. One reveals more air around the instruments, the other suggests more bite( treble like).  I learned this more bite is a slight lackt of "peace" When the balanced "mother of all transformers" ( i learned it weighs 82 kilo's) is in the chain more "bite" dissapears, it becomes much less hifi like what we take for granted so easily when we listen thru systems (including tubes!)

The noisefloor you will have with normal pwr supplies in audio gear (including Krells and Proceeds) and current from the wall is subliminal. You are not aware of it unless you loose it.

The first time I met this silence in my listening room it was almost a physical "attack" to my ears. Dead silence is not pretty. Research found out that the slight hissing from air conditioners in libraries was much more relaxing to readers than without it. However when playing music you hear so much more. The drawback is the silence in between tracks on the cd becomes very artificial and begin to stand out. they do stand out against the  background of the recorded  "act"

another example, you hear reverbation decoupled from the human voice, while first they seem one. you hear recording tricks, you hear the "signature" of the recording engineer. All this with the AKSA's of course  

[andyr]

The difference i hear when reversing the leads is always subtle but consistent. One reveals more air around the instruments, the other suggests more bite( treble like). I learned this more bite is a slight lackt of "peace" ...

Kyrill,

Thank you so much ... this is the first time I have heard anybody living outside of the good ol' USofA say they have heard a difference when reversing AC phase.

Now I have a lot of experimenting/listening to do!

Regards,

Andy

[kyrill]

Hi Andyr

It must be quiet in yr room
Ask a (beautiful, but not necessary.. but it helps) lady to listen with. My wife and youngish childeren(14-17 yrs old)  hear the diferences easier than I do
The more bite is "rougher" it hears more "dynamic.  actually my sons prefer the "wrong" configuration. but their reference isMP3's on a mp3 player.

Before my balanced "galvanic separation"transformer, I started reversing the leads with the  cd player. then with the pre amp and finally the pwr amp.
But as all is synergestic co-intertwined with each other, with the new configuration i reversed the cd player again if it still sounded best in the new context.

[DSK]

Andy/Kyrill,
I tried the reversed polarity on my AC cords about 18 months back when I was playing around with earthing combinations in an attempt to eliminate a small hum.

From memory, my observations were similar to what Kyrill heard. Swapping polarity had slightly more treble emphasis which initially sounded like more detail, but over time sounded fatiguing. Reverting the polarity was more relaxed and natural sounding to me. The differences were quite small, and less than those observed by lifting the earth wire on various components. At one point I had the entire system floating and this was the quietest background I had heard. However, a strong resonance (charge?) could be felt when you put your hand against the front panel of the CD player which was a bit disturbing. Over time, with changes of equipment, cables etc, I have ended up with everything grounded again, no hum audible at the listening position, no resonance/charge on the CD chassis, and more peace of mind. I don't really feel I have lost anything.

About 4 or 5 years ago, I auditioned an Australian balanced power supply made by Peach Audio in NSW. It retailed at approx AUS$2000 and was rated to 1000w (enough for my front end only). It certainly made the background quieter. The music took on a more soothing, flowing, rounded type characteristic which was quite nice, but ultimately I felt that it softened the leading edges a bit too much and didn't buy it. Plugging the TV into it caused a nasty buzz. My system back then didn't have the resolution that it does now and I would love to try another balanced power supply one day.

[cmscott6]

Just curious for US listeners.  How do you reverse plugs/polarities with polarized plugs?
 
Edit... Sorry, just reread post and, yes, rewiring the receptacles "backwards" would do the trick... Or even a non-polarized extension cord... wasn't thinking.

BTW, in keeping with the original spirit of the post, I just tried two Black Gate NX Hi-Q caps in super-e configuration for C1.  Seems to liberate even more bass response from the GK-1/Aksa 55 combo...

[Gordy]

Hello CMScott,

Your local hardware store sells cheater/adapter plugs for adapting three prong plugs to two.  They run (about) $1.59 are generally used by those who want to isolate the ground on a unit.  If your sample has a polarized prong, simple file it to size.

[andyr]

Andy/Kyrill,
From memory, my observations were similar to what Kyrill heard. Swapping polarity had slightly more treble emphasis which initially sounded like more detail, but over time sounded fatiguing. Reverting the polarity was more relaxed and natural sounding to me. The differences were quite small, and less than those observed by lifting th ...

Darren, hi there.

I presume you mean when you want back to the "normal" plug wiring, the moosik was more relaxed?

Regards,

Andy

[cmscott6]

Good point, Gordy.  Thanks!  I even have to use those in my house sometimes.   (Ahh, old wiring and plaster walls   )  I forgot that those don't have polarized plugs...

[DSK]

I presume you mean when you want back to the "normal" plug wiring, the moosik was more relaxed?

Hi Andy... Yup!

[Occam]

The easiest way to reverse polarity on your mains is to use an on-off-on dpdt switch that can be wired so that the two 'on' positions provide reversed phases, and it still works as an on-off switch. This has the major advantage of actually fusing the 'hot' wire even with reversed phase, If you've a short to chassis, it might actually preserve your life. Its also far more flexible and eliminates the intermediation of intervening cheater plugs.

Hugh has some lovely 15A-220v/20A-120v, toggle switchs with a very cool matte black bat. (I'm prejudiced as I actually found these for Hugh). So next time you order from Hugh, consider getting a bunch.

Ideally, all your components should have this mains phase reversal capability. This not only helps to minimize hum, but for the obscessive, allows tweaking for the 'blackest blacks' and depending on the component, actual tonal characteristics. Specifically, the Atari/Stancor 3.4A 9V AC table wart powersupply commonly used to power an ART D/IO a-d/d-a has an unpolarized plug, and its best orientation is immediately apparent. This is especially obvious in the bass, but the whole character throughout the spectrum is markedly improved.
Why?
Its the goober dust.....

[MikeC]

The phase reversal and balanced power discussion is fascinating     , but I'll go back to Losts' original question.

For my future "bass deficient" dedicated 100W AKSA bass amp   , I am planning the following:

Lower voltage supply rails (42V).
50% greater reservoir capacitance.
Higher current rated rectifier diodes.[/list:u]

This is to drive paralleled 8 ohm drivers with an impedance minimum of 2.5 ohms, so the increased current capacity within the output stage SOA might not be necessary with a single 8 ohm speaker.

I have discussed this with Hugh, and there should not be a problem implementing this, but there will be trade-offs in the mids and treble. This is not a problem for a not deficient

BASS amp. I can't tell you how it works out, but I will once I get it ordered and built up.

Cheers

Mike

PS: In case anyone doesn't get it, I think any suggestion the AKSA has too little bass is ludicrous.