Because of Purepower 3000 power was not enough for my high power ss system then I bought an ABB 18KW UPS.

Both APC and ABB are popular and my friend used APC and the sound of APC was not good and I choosed ABB to test between Wall AC and ABB.

ABB from Switzerland produce high quality UPS and last week I have listened to one of them (ABB 20KVA model) in my system.

After break-in process I have connected different parallel loads (500w, 4000w, 5700w) to ABB UPS to view what happen to sound quality.

ABB UPS vs Wall AC Power (when wall AC is good) :

ABB is like high power low impedance Mark Levinson Amplifier : clean but Compress , thin and damaged harmonics.

Wall AC power (when AC is good) is like Zero feedback good Amplifier : Rich Harmonic, dynamic and better more 3D Image

ABB has no limits in current delivery (18,000W , 100A) and it has superb jump and attack but no decay no harmonic no life in music.

you can feel the compression of sound when the ABB in online.

I do not know but I guess most UPS and Inverters like ABB , APC , ... use feedback to regulate voltage and their sound reminds me bad Computer playbacks.

Purepower is like bragin and If Richard had a 30,000VA purepower then I was his first customer. I told richard if he can help me to design a high power Purepower but I think it is not possible to him.

Totally I think no UPS in this market is good for sound.

In the next step I will go for testing Kevin power System. 12v battery + 6 parallel Victron Energy (total 18000VA).

If Victron will not be good then I will go for delicated 20/000v to 380v transformer .

rowuk wrote:

My opinion is that if a device sounds bad on bad electricity days, that device is bad - not the AC supply. The best that we can hope for is to change our listening times where the AC supply is supposedly not as corrupted (also an assumption).  We need to demand that our amps and preamps as well as sources are properly built for the environments where they are typically used. I find threads like these are totally useless as we have no process for defining better - rather only the typical "high end" BS terminology. Do I care if Amir suffers? No. In my opinion, he needs a better process, not more gear.

RF at Ona wrote:

Romy and friends, Reading about the sensitivity of your system to electrical power supply problems reminds me of the days when I used to make my own equipment as much for the learning experience as for the final result. One of the mundane things I learned is that standard audio equipment, including shielded cable connections, did not (and possibly still does not) follow good GROUNDING practice. You connect the stuff in the usual way and you are bound for problems. The sensitivity of your low-level equipment, the success of using battery supplies on some sources and the inability of line filters and conditioners to alleviate the problems without causing other problems suggests that you might look again at the grounding in your system. Remember, a grounding problem does not always result in hum or any noise in the absence of signal. Grounding problems are dynamic and disturb the signal and so can masquerade as or exacerbate a power supply problem. At the risk of stating the obvious and trivial to experienced practitioners:   1) Cable shields should be grounded at only ONE END, otherwise you are providing multiple ground connections between pieces of equipment.   2) The single cable shield connection should be connected to the internal central ground point by wire not by chassis. Usually, the cable shields must be disconnected at one device's connector.   3) Sometimes, one cable shield of a stereo pair is connected at both ends to make the ground connection between devices but this is not as desirable as a single separate wire for grounding each device to an external central ground (STAR grounding instead of cascaded grounding). Remember a cable shield is intended to reduce noise, not carry signal or ground.   4) The system as a whole should be carefully grounded. Sometimes household grounds are inferior and a high-quality separate connection to a good outside ground is needed (a subject in itself).   5) You may have a stray voltage problem.   6) Your audio system might benefit from a dedicated power line, isolated from other household appliances.   7) If you live in an apartment building consider moving. Grounding, so basic and simple, can be a subtle and tricky thing. It is important but cannot be perfect and therefore always suspect. The more problems that involve the low-level equipment the more I would suspect faulty grounding and shielding at least as a contributing factor. It should be obvious that the more extensive the system the more likely the problems. On the other hand, where grounding turns out not to be much of a problem, I wonder if the new high voltage battery technology used in hybrid cars might be useful at least for the true audio obsessive. Regards, Robert

I remember Romy lifted earth wire and floated his system some years ago.

all of My system CD/Pre/Power are isolated from earth wire, it means by factory default all AC input plugs have two pins (only Line and Neutral) not three pins.

all chassises are floated and there is no ground loop across AC cables. 

I have connected one of the chassis to earth wire but dynamics decreased. the best sound come from my system when the earth is lifted.

It seems the earth wire is not necessary for all audio systems. 

rowuk wrote:

The whole idea of an earth wire is a path to ground if something fails in the unit. In most countries the (metal) case is attached to this pin on the power connector. It is incredibly stupid (and in many countries illegal) to lift the earth wire and provide no path for saving your life. That is different than not wanting to use the earth in the power receptacle.

Paul S wrote:

All that has been discussed at length many times this board. It seems that people continue to confuse neutral and ground, and I agree that it is confusing. Basically, any commercial "power company" power grid supply in the US will be grounded at a service entrance breaker box, and all neutral and also any ground wires will be routed literally to ground near the service box. Again, the neutral (typically white) wire between the component and the wall outlet IS connected to the service ground. A ground wire, so-called, is to ground "stray current". Ideally, "properly made" components are star grounded, so they not only do not need a ground wire, but using the ground wire can cause a ground loop. As for grounding cable shields, I just go with what "works". In an all-balanced system, everything is grounded. Best regards, Paul S

rowuk wrote:

The whole idea of an earth wire is a path to ground if something fails in the unit. In most countries the (metal) case is attached to this pin on the power connector. It is incredibly stupid (and in many countries illegal) to lift the earth wire and provide no path for saving your life. That is different than not wanting to use the earth in the power receptacle.