Line Conditioners or Not and Why

George Fredrik Fiske posted:

Huge posted:

Hi Richard, the trick would be to drive the whole thing using a 78, as they don't have RIAA equalisation.

Huge you may like to have a look at this non-cmmercial link concerning the EQ used for 78 recordings.

http://www.mil-media.com/pdf/M...078%20EQ%20Chart.pdf

ATB from George 

George, that was tongue in cheek.  I think my mechanical amp would achieve an HF 3dB point maybe as high as 5Hz, if I'm lucky.  So it wouldn't even properly reproduce the wow from a 78! (it might get the wow from a 33&1/3).

OK, I didn't realise the 78 situation was quite that bad!

Huge got you.. In my mind I  had the springs as the load, and the stored energy represented as the potential energy (using gravity) of the displaced weights. But yes I see where you are 

HUGE

What would be an analogy for a power conditioner and its effect on a power supply ?

Now if we use a power conditioner as a device that restores the power factor this should be interesting.. Huge might need to create a new dimension.  ... What a fun thread..  Hmm perhaps some analogy of relative displacements to a master reference..

TOBYJUG posted:

HUGE

What would be an analogy for a power conditioner and its effect on a power supply ?

A flywheel on the far end of a semi flexible shaft, with the eccentric disk (and it's worn bearings) on the other.

Depending on how the bearings were worn and the mass and shape of the flywheel and the flexibility of the shaft, this could either stabilise the eccentric disk, or, more likely make it wobble even more violently.

Simon-in-Suffolk posted:

Now if we use a power conditioner as a device that restores the power factor this should be interesting.. Huge might need to create a new dimension.  ... What a fun thread..  Hmm perhaps some analogy of relative displacements to a master reference..

AAAARRRGGGGHHH! 

Huge posted

George, that was tongue in cheek.  ...

OK, I didn't realise the 78 situation was quite that bad!

Dear Huge,

It is worth remembering the EMI 78s out-numbered all others at the time in Europe, so mostly the standard was that set by EMI. Small independents did tend to be highly individual in the styles though! But for most people buying readily available, HMV, English Columbia, Regal, Parlophone [etc, all being EMI companies], the EQ of 78s was standardised. 

But it is a common misconception that because 78s did not use RIAA, that they did not use encoded EQ.

ATB from George

Dear all and especially Huge, thanks for your contribution as well as the excellent explanation/analogy, which i must admit i need a sketch or something similar in order to understand it fully. I can follow it that far, then i get lost trying to picture the connections etc.

However, it is now clear that the only real value line conditioner would be a regenerator, which of course would be a very expensive option, unless one has a very expensive ultra high end hifi system (and i don't).

Perhaps a good quality UPS with good storage capacity would do the trick of clearing the mains from noise and other interference?  If a hifi system was powered up from the battery of a UPS, wouldn't this be a clean power supply?  I am in the process of buying a PSU for my Project RS Phono Stage, and this fundamentally comprises a lithium battery unit which can drive the phono stage for 60 mins without the need of the mains.  If this works, then a bigger UPS for the entire system should also be beneficial, and i do not think they are so expensive, but i am not sure.

Lets say the average hifi system burns 400W, then for one hour's usage one would require a battery storage of approximately what capacity?  And if so, what would be the average cost of such UPS?

Ok UPS are great for certain applications, but audio might not be one especially if providing mains power. Most if not all mains UPS use batteries and then inverters. These inverters electronically reconstruct an AC voltage and current sine wave. However sine waves can be quite hard to accurately reconstruct without added noise.. so you might find your UPS add a whole lot of electrical noise on the mains whilst the inverter is active. If you look at the blurb of quality UPS you see this mentioned and how they approach reconstructing the mains.. but at the of the day it will almost certainly not be as good a quality as your direct mains.. For computers and the like this won't matter (much) but for audio components it might provide disappointing results.

Simon

Yes, A regenerator is basically what the Naim R&D guys reckon is best, but there's a problem.  Something about impedance again and the need for the regenerator to ideally be the size of a house, or preferably the size of a small power station...

We need a nice discreet battery installation like this..

Discreet indeed. The curtains make it all but disappear into the room. But now we've probably introduced the dreaded hum issue.

Hi Richard,

So a small, stable, low impedance UPS like this then?

Sizewell B...

Best regards, FT

FT, that looks OK.

Here's ours.  So long as you don't look in the back yard, you'd never know it was there...

I thought with all this talk of mains impedance, we should actually calibrate what we mean. There is an expected mains source impedance at the master CU and according to IEC725:1981 this models the European domestic mains supply as having an impedance of (0.4+j0.25)ohms. I understand in the UK we tend to have a slightly lower impedance than this (which is good). 

Therefore if one is looking for a regenerator for the audio equipment one should enquire as to its source impedance and it preferably should not exceed  (0.4+j0.25) ohms. (IMO of course)... and this doesn't mean the regenerator has to be physically massive!.. 

Simon

I use one of these, brought back from my time in Malaysia.  Technically  its a shunt reactor which stabilises the mains voltage and absorbs and generates reactive power as needed (i'm told).  It works for me

I haven't read the whole of this thread, but I did like Huge's mechanical analogy descriptions.

We live in an imperfect world. But those old elctro-mechanical devices called "Record Players" or "Reel-to-Reel Recorders" seem to be able to provide emotional enjoyment like nothing since. Not everything mechanical is worn or wobbly to the extent that it "fails" from the off. For example, several of our training aeroplanes have variable-pitch propellors with constant-speed units. Mechanical governors, hydraulics counteracted by springs, rotating blades at 2,500 rpm and yet that 2,500 rpm remains "rock" steady and "sweet", despite my attempts to dive, loop, roll and thereby load the prop and engine.

Even Sizewell and the other nuclear plants generate steam to drive a turbine on a semiflexible shaft to get a rotor to spin. Semi-flexible because back in the early 60's IIRC the CEGB found shafts breaking because they were too stiff ! so changed the design.

I digress - power sopplies are important. Especially, smooth, steady, reliable ones, with plenty of reserve. Long-live electro-mechanics....................just don't get me started on GPS timing and jitter................

Hi Don,

"Real to Real () recorders" yes, but I never found "Record Player" satisfactory.

And you have me at a disadvantage: The only aeroplanes I've flown had fixed pitch props.  Flying with variable pitch and a constant speed unit must give a significantly different feel during manoeuvres.

However, on to my real point.  I believe the high cost of those propellers and constant speed units reflects their engineering quality and their ability to perform.  Whereas the low cost of the typical domestic supply into a house and the associated meter and CU reflect their engineering quality - adequate, safe and reliable enough for the normal job expected of them (e.g. powering a washing machine).

I believe we are demanding, or at least wishing for, a degree of engineering quality from the electricity distribution system that so exceeds the requirements of most people that it's general provision would be economically unrealistic.

Unfortunate, but reality does have a habit of creeping in to spoil the party. 

Richard Dane posted:

Yes, A regenerator is basically what the Naim R&D guys reckon is best, but there's a problem.  Something about impedance again and the need for the regenerator to ideally be the size of a house, or preferably the size of a small power station...

Indeed, theoretically a specially designed regenerator would be the answer.  However commercial ones generally create a "Modified Sine Wave"; i.e. their output waveform is distorted rather than the pure sine wave we need.  Electronically generating a true sine at high efficiency is problematic (I don't know if it's even possible), hence lower efficiency, and to get the low impedance requires a lot of 'power reserve' hence large volume.

A more viable option may be a huge (50kg+) bank of Pb, or better, NiFe cells directly powering the DC voltage rails of the equipment with a charger system that disconnects when the system is 'on'.  As this is Naim, the charger would also keep the equipment in 'hot condition' when not in use.  Sort of like an overgrown Hugo power system.

Huge some large commercial regenerators work more akin to your earlier illustration - a motor is used to spin an axle with a massive fly wheel on it - this in turn is then used to drive an ac generator... i understand they work well - and of course there is no quantisation noise as such at recreating the sine wave.

There are very accurate sine wave signal generators of course , and I can see in theory such a signal generator at 50Hz could be driven into a large power amplifier to regenerate the ac mains power - but I am not aware of the specifics of any design on this

Simon, that's exactly why I specified "Electronically generating a true sine at high efficiency is problematic".

Using an accurate small signal generator and power amp is the obvious solution, but this has practical problems.  The obvious choice is a Class D amp, but then you have to remove the carrier frequency and the filter for that inherently creates a high impedance at that point - not what is required.  The next choice is class AB (or multilevel variants thereof).  These work but are inefficient (maximum efficiency rarely exceeds 60%) and also need overrated power supplies to operate properly at sustained power.

So what is the target?, to drive a high end power amp.  Now most high end power amps have much higher output than Naim, so say 250W per channel.  500W Class AB output implies about 1k2VA to 1k5VA power demand, so design for the latter.  The re-generator power amp is 60% efficient so it's demand is 2k5VA and it has to dissipate at least 1kW of heat (may be more at some operating conditions).  1kW continuous at moderate heatsink temperature requires a heatsink area of about 0.5 sq m (huge).  Not only that but the SMPS required to drive this (at 90% efficiency) has to be rated 2.77kW.

That's a serious power demand for a 250 wpc amp!

Using an electro-mechanical regenerator also has it's problems.  To avoid large amounts of electrical and EM noise being emitted, both the motor and generator should be brushless.  The motor should also be synchronous, as otherwise a sophisticated control mechanism will be needed, unfortunately high power brushless synchronous AC motors are difficult to start when under load.  To keep Naim equipment 'on song' in needs to run 24x7 so it needs to be very quiet.

Quite a list of requirements, and there's probably others I've missed!

Huge posted:

Hi Don,

"Real to Real () recorders" yes, but I never found "Record Player" satisfactory.

And you have me at a disadvantage: The only aeroplanes I've flown had fixed pitch props.  Flying with variable pitch and a constant speed unit must give a significantly different feel during manoeuvres.

However, on to my real point.  I believe the high cost of those propellers and constant speed units reflects their engineering quality and their ability to perform.  Whereas the low cost of the typical domestic supply into a house and the associated meter and CU reflect their engineering quality - adequate, safe and reliable enough for the normal job expected of them (e.g. powering a washing machine).

I believe we are demanding, or at least wishing for, a degree of engineering quality from the electricity distribution system that so exceeds the requirements of most people that it's general provision would be economically unrealistic.

Unfortunate, but reality does have a habit of creeping in to spoil the party. 

Which may be the reason line conditioners exist gentlemen. 

It can not be that these companies employ many engineers and designers, they produce things, spend hours or days testing things, then offer them to the market. 

There must be some merit into their products, otherwise they would go out of business. 

This morning I discovered that my Mac mini , which I use as my music library server, generates some noise that is picked up by the phono stage. Very annoying!!!  In the end I decided that I have to have it off when I play my records. Maybe I have a very sensitive phono stage, not sure.  I will wait for the dedicated PSU of the phono stage to arrive and hope this issue will not be there any more. 

Huge posted:

That's a serious power demand for a 250 wpc amp!

Oh yes... But it should be be clean 

Having said all this I think HF filtering and good low impedance direct mains source would be preferable... I suspect only if you have flicker problems: IE small fluctuations over a small time period I really can't see that a regenerator should add much.

Simon

Simon-in-Suffolk posted:

Huge posted:

That's a serious power demand for a 250 wpc amp!

Oh yes... But it should be be clean 

And it'll heat your house quite effectively whether you want it to do so or not!