Poll Question: Power Conditioning

[One and a half]

System so far as per the picture.

 

The furman sequencer provides a way to switch on and off the components, so there's no loud pops at start or end, plus it senses high or low volts. If such a problem existed, it shuts off all the relays until a restart. The audio components therefore don't see the filtering on the Furman. Relays btw are Idec RH4, rated for about 6A inductive loads.

The pairing of the isolation transformer to the Equitech is to provide slowing of pulses on the primary of the Equitech. Since much of the asymmetric noise is absorbed by the balanced supply, there's not much need in the way of RLC devices in front of the audio components, so these aren't fitted.

The Mac Mini is also on the same supply, it's benign as far as introducing noise to the other components as far as harmonics go. RF noise out of the mini is quite good, the backgrounds are dark, with great low level detail, can't ask for much more. Being totally passive, the reliability versus an inverter output are night and day.

 

There will be comments about earthing, and RCBO, these are all fitted to rules where I live and need to abide by them. All earths are bonded together.

 

[One and a half]

Great thread revival ! Can we also have some European recommendations too ?

 

Also some commentary on dedicated spur, and separate external earth with metal spike in driven into the ground ?

 

A separate metal spike in the ground for a protective earth is often illegal in many countries. The danger is, should a fault current occur, the fault travels to the wrong earth and bypasses the protective devices, so that's not a good thing at all. There is nothing to stop you to put 500 (exaggeration) or more spikes in the ground, and bond them together to form one complete earth. Or sheets of reinforced gal steel bonded together buried in the ground, so long as ONE connection to all the other earth connections in the house are made.

 

I prefer to roll my own, there is a UK manufacturer of power conditioning gear, the prices receive a lot of resistance so to speak. This mob seem a bit more realistic.

 

Dedicated spurs will give you control and protection for your audio components. A spur line on its own will and can be susceptible to conducted noise, so is best treated close the source with an isolation/balanced transformer.

[One and a half]

To 'One and a half' so the Furman Sequencer only provides control functions put does not power any of your components?

 

Yes, the Furman provides on/off control via the relays only. The Furman has over and undervoltage protection, so the transformer ahead of it will reflect those variations and the protection system will switch off the output, relays in this case.

 

I have tried a Monster Power Center (230V version) ahead of the Equitech, instead of the iso transformer. There was a reaction between the non linear pulses drawn by the load and the caps/filters in the Monster, and the music sounded very thin. The current pulses amplified, perhaps there was some ghastly resonance going on, but not enough to activate the protection system. Reinstating the iso transformer removed the problem of the higher peaks and the music's fullness returned.

 

Using the same Monster on the output of the Equitech was not successful, the device was expecting an earthed neutral, didn't find one, and either tripped right away or waited for several hours, then tripped. I use the Monster now to protect servers, printers, IT type loads on the regular TN system.

[One and a half]

What power conditioner are you using?

None, I have no need.

- I live in Europe where power is stable and relatively clean.

- I exclusively use professional equipment that naturally has all needed power filtering.

I did work for APC as a Technology Strategist, and yes we made tons of money off Americans who often lives with a power quality usually only found in poor undeveloped countries.

 

Wow. You have measured the AC line, and no harmonics or common mode noise enters the internal DC circuits or are coupled to the output?

[One and a half]

My DAC and power amp have no earth connection, so I am thinking of grounding both of the chassis to a true earth

 

any thoughts ?

 

No benefit. You would need to analyse the interior circuits carefully, and you could violate the manufacturer's certification for connected to the AC supply.

[One and a half]

Stable and relatively clean?

 

Here in Denmark, 230V is standard, but variations from 207 - 244V are officially considered "satisfactory". I use AC regenerators to ensure constant 230V.

 

Right now, early on a Saturday afternoon, my Power Plant Premiere measures 2.6% THD in. After AC regeneration, THD on the output drops to 0.6%.

 

I have seen the 2.6% or thereabouts THD in quoted a few times by people independently. This I believe is the distortion generated by the Power Plant itself. It's not much a big deal, since the output is cleaned up. Would be interesting to see a fourier of that distortion.

[One and a half]

The question is whether or not some fluctuations will actually have any influence on the sound quality. I remain skeptical. The PS-audio perfect wave 3/5/10 cost so much that I believe you can better spend the money on speakers/DACS etc.

 

Voltage fluctuations have little effect on SQ since largish caps can replenish the load quite well for linear supplies anyway.

 

The issue with AC mains is the noise that is conducted whenever a light switch goes on in your home, and the unwanted odd frequencies that are manufactured when AC passes through a diode.

The odd harmonics multiply, and being higher than 50/60Hz, they are easily coupled via a transformers parasitic capacitance and enter the amplifier circuit. Unless these are removed, this noise finds an easier path back to the source, usually via single ended interconnects to other equipment along the way.

 

The PWD devices create anti odd harmonics, thus the distortion due to the harmonics are nullified.

[One and a half]

@GeneZ, Power conditioners in the classic sense are those with a filter, the purpose for which is to filter out mains problems.  For HT, about 5 years ago I bought  a Monster conditioner with the filters, and protection circuits. When there was a power failure, the unit dropped out and switched off the loads, and waited for a time for the voltage to stabilise and switched on, for that purpose it worked. In an audio system however, pulsed (harmonic) currents from amplifiers in particular create havoc when they react with the resonant frequencies of the filter. Rather than block frequencies that don't matter, there's a worse mess where harmonics circulate from the amps to the conditioner and back . The ideal situation is to measure the harmonics from the amp and then create a tuned filter to create an impedance null to remove them, but no one makes this device for audio.

 

Power conditioners with LC filters create more mess and do nothing for connected loads.

 

The best and cheapest way to protect audio equipment from surges is to use iron, and lots of pounds (kilos) of it in the form of transformers that actually resist the lower harmonic frequencies and use balanced wired systems to clean up the mess. 

 

The Monster is decommissioned and also a Furman sequencer which has a power conditioner that I used for IT equipment went belly up after 15 months and intermittently fails on me, so it's being replaced with standard rack mount power strips and a Topaz 1kVA transformer for transient suppression.

 

Voltage tolerance. Audio components usually are spec'd at +10%, -15% of line voltage. This is fine to cope with variations, the output will still work fine, and produce the same power and transients as if the input voltage were steady, the equipment is designed to do this.

 

A regenerator like the PS audio designs are UPS without the batteries. They spit out common mode noise and cause more problems. However a regenrator with a transformer on the output will reduce the noise somewhat if the (isolation) transformer has low capacitance between the windings and is built like a tank.

 

References:

 

Why isolation transformer is used at the output of online UPS?

HERE’S WHY YOU SHOULD USE AN ISOLATION TRANSFORMER IN UPS SYSTEMS

Functions of Isolation Transformer in the UPS

Purpose of isolation transformer in UPS ?

[One and a half]

20 hours ago, Ralf11 said:

I also was able to get the electric co. to come out and measure noise on my AC line (at the meter) - there is a thread about that on here.  They did not find much at all.  I was planning on buying a Topaz, but deferred that purchase after getting the data.

 

 

Well, you didn’t account for the risk of overvoltage when High Voltage power lines fall on lower voltage lines during storms, other severe weather events or malfunctioning cable support systems like insulators.

Since the Topaz is a very good surge suppression device, all your equipment can be fried at any time due to a spike since you deferred the decision to buy a Topaz.

 

Not a wise decision to defer purchase is it. Typical of a know it all. More rookie errors. 

[One and a half]

3 hours ago, Ralf11 said:

Surge protection belongs at the main panel - every audiophool genius knows that.

Right, so you have surge protection installed at the panel? And the rest, what else is their sacrificially in front of the audio system, in case the surge protection lets through too much V? 

[One and a half]

4 hours ago, GeneZ said:

   Eliminating that cross talk is what makes a system at its best.   Matter of fact?   Without it, it could be seen as counterproductive.  Might as well plug back into a plain AC outlet strip  For, all it takes is one noisy digital component kicking back into the line its noise, and they all become the same.  Its not saving money.  Its buying a placebo effect.

 

Eliminating cross talk or conducted noise shared on the same power line is, on paper possible, but in practice another issue.

 

Noise for the upper frequencies can be taken care of by filters such as the Schaffner type. Typical circuit is shown here and its performance graph are are made for compliance issues.

 

The sizing of the filter has to be rated to the current draw, since the inductors (2xL1) are the limitation. From the graph, into a 50 Ohm load (doesn't exist practically, but it's the standard Schaffner and others use), the peak attenuation is at 15 MHz, with the worst attenuation at less than 10kHz. This type of filter is the reflective kind and is common in many equipments. In other words, frequencies in the domain of the filter are reflected back the source. So in some respect, using a filter like this achieves some level of crosstalk reduction. This raises another problem with the audio component, the additional reactance and capacitance in the circuit, typical of most line conditioners fall into where the sound is rough and better off without the filter in the first place. 

 

For frequencies above 50/60 Hz to about 5kHz something, the counter productive harmonics, absorption filters are the best type, the amount of harmonics need to be measured, then a filter designed to be an impedance null for those frequencies. It's like a bucket where unwanted frequencies fall into, but the bucket can get full, saturate and electrically, the filter being of the absorbing kind develops heat. 

 

I found like many others at CA to use a split (balanced) AC power to at least trap unequal harmonics and for RF, the Topaz has natural filtering, although most audio designers worth their salt take care of PCB and avoid propagation of noise to interfere with their own circuitry. Common star grounding is very important, no daisy chaining power strips, another topic.

 

More references:

 

Understanding Electromagnetic Compatibility Standards for Switch-Mode Power Supplies

 

EMC Design Techniques

 

Schaffner data sheet series FN9255

 

FN 9255.pdf