Experience with power conditioners?

[fas42]

Have done experiments myself, creating DIY units  - they can form part of the answers; an audio friend just down the road has used them, the commercial isolation transformers, for years, and it's certainly easy to hear the benefit on his setup.

[fas42]

1 hour ago, Ralf11 said:

what's wrong with your power that a conditioner will fix?

 

Simple answer is that audio gear is not sufficiently robust to reject noise coming in via the mains power feed - so, need more rejection; keep doing this until you can't hear audible differences.

 

I have found that it's very difficult to kill off any impact entirely - the real solution is to make the audio components more capable on the inside, which is not something taken very seriously, unfortunately.

[fas42]

9 minutes ago, Ralf11 said:

No, I am asking him to quantify or describe the noise on his powerline.

 

Sufficient to impact the perceived quality of the audio system - no numbers, the simple process of plugging and unplugging various "noisy" electrical devices on circuits in the home is the "tool" that tells me whether I have adequate 'robustness' or not. The noise coming in from externally is a meaningless thing to measure, because it will change every minute, depending upon what neighbours are doing.

 

The only solution is to assume extremely noisy, "dirty" power is all one has on tap, at any time. Then the job is to engineer the audio equipment so that it's completely impervious to that environment. As an example, a previous system was sensitive - as are many - to arcing somewhere in the mains circuit - you literally heard the noise of this directly in the speaker sound. So in this instance I designed a noise suppression filter for the mains - which did the job; no noises were then heard, even with severe injection of arcing interference.

[fas42]

48 minutes ago, Ralf11 said:

Hiss?  or Hum?

 

 

If you are referring to the sound manifested from the arcing this was a scratching noise, something like a cat at the front door wanting to get inside.

 

The typical impact from noisy or poor quality mains is not hiss or hum, it's a drop off in quality, some of the sparkle and life in the playback goes missing ... imagine someone covering the tweeter with a heavy layer of cloth; it's an artifact that has that type of presence, subjectively.

[fas42]

41 minutes ago, Ralf11 said:

So, when you remove the noise coming in via the mains power feed, it sounds as if a veil over the music has been lifted?

 

Ahhh, the notorious audiophile "veil" - not really, I just thought of another analogy: an audio friend down the road does both vinyl and file player systems; on the vinyl it might kick off nicely on an LP, then it starts to go dead, it loses its mojo - what's going on?! Aha!! Lift the cartridge, a big wad of fluff is firmly wrapped about the business end - carefully remove, needle down again ... and SQ restored.

 

That sort of thing - so, we're getting rid of system "fluff" ...

[fas42]

3 hours ago, Ralf11 said:

 

use the term transparency if you like - I posted on the notorious veil in another thread a minute ago

 

I am going to assume you did not do blind testing, tho correct that if it is wrong, but I'm still interested in your impressions

 

Did you hear anything when no music was playing?

 

And, in what type of music did you hear an improvement?  orchestral? or other high DR?

 

 

 

Transparency is a good one.

 

No, I don't hear any noise when the track is musically quiet - if there is a strong acoustic encoded in the recording then I might be be tuning into the sound of that. But I am not aware of the system in itself being noisy in any fashion - the only example I can think of in the ones I've played with over the years is the current NAD combo: in the very early stages of sorting it out there was a period when it did sound noisy, there was an electronics "hissiness" which then disappeared as it steadily improved.

 

All types of music benefit, from the most dynamical extreme, to highly restrained classical - that key element of convincing life in the musical goings on is lifted in strength; that, which makes one want to keep listening, no matter what's playing.

[fas42]

40 minutes ago, gmgraves said:

 On top of noticing the grain in the 35mm print, they would never be able to look at that print again without seeing the grain immediately! That's the way my system sounds with and without the transformer in the mains circuit. I.E., I never noticed the grain before I installed the transformer, now I hear it instantly when the transformer is not in the system.

 

Yes, that's the way with a lot of the improvements that one can make with systems. One doesn't realise that there is a disturbing, audible quality in the sound - until you do something that gets rid of it. And from then on you always notice it - this figures in almost every area of the audio adventure. The good news is that when all of these "unknowns" are dealt with, then glorious, convincing playback emerges - there are no downsides!!

[fas42]

Getting conventional power supplies to work reasonably is not trivial - if one  ignores the gross over-simplification one reads in textbooks and investigates what actually happens in a real power amplifier, then it becomes quite a challenge to make them work properly. The Philips HT box I played with with years ago had most of the work done on the power supply feed area, getting it to run as cleanly as possible - which allowed the low powered amps to give of their best. A DIY chip amp I designed and built was 90% power supply, because getting the voltage rails super clean was key to making the sound work well.

 

This is why doing almost anything to the mains coming into a component changes the sound - the lack of attention to detail of the design of the supply circuit means that the rest of the circuitry inside is extremely sensitive to what the mains is like.

[fas42]

19 minutes ago, Ralf11 said:

what actually happens in a real power amplifier?

 

The amount of energy needed to drive speakers with music having heavy bass content overwhelms the ability of the mains-transformer-smoothing caps to maintain delivery - the voltage rails sag, and modulate, badly; parts of the supply circuit ring with very high frequency rubbish. This is why amplifiers like Krell get such a reputation - monster transformers, etc, get around this issue to a good degree; the alternative is to have self powered subwoofer, or similar - transfer the problem to electronics that only worry about the bass region.

 

I've done much playing with Spice modelling real power supplies handling typical mains, with realistic power supply parts, feeding an amplifier handling big bass frequencies - the voltage rapidly collapses, and can cause the amplifier to clip, it runs out of headroom.

[fas42]

8 hours ago, jabbr said:

This would be readily apparent in THD measurements. If your SPICE model shows "high frequency rubbish" then you probably need better snubbers. DIYAudio has endless discussions on amplifier design and a subforum on power supply design -- if you post your SPICE model there folks would help you out.

 

THD and suchlike may be very deceptive because they refer to the DUT being in an equilibrium with respect to its operating conditions - and that's one thing an amplifier while playing back music is most certainly not. Depending upon precisely the type of music being played and the volume, the circuitry is in a constant flux, changing endlessly, with respect to voltages and temperatures - steady state measurments are quite useless for assessing the meaningful characteristics of the unit.

 

Yes, snubbers are needed - and, virtually no audio components use them; I went through a phase of adding these to ordinary audio consumer items, and they all benefited markedly.

 

I used to be very active on diyAudio - and played a major part in a long running thread on understanding the inner workings of power supplies - so, been there, done that.

[fas42]

47 minutes ago, Ralf11 said:

playing a major part in a long running thread on the internet is not the same as played a major part in designing digital electronics after getting an IEEEE degree

 

Not quite sure how this is relevant to making an audio power amplifier behave well ...

[fas42]

1 hour ago, Speedskater said:

The point is:

Marce knows a lot about circuit design, while many poster on many audiophile forums don't.

And why specify audio power amplifiers on an AC power thread?

 

Not arguing with anything that marce says - I've parried with him over minor details, and viewpoints, in a previous forum lifetime - yes, he knows his stuff ...

 

Audio power amplifiers are the real meat of the AC power problem in most audio situations - because they demand transient, heavy spikes of current from the mains supply to feed the typical power supply smoothing caps; other audio components have requirements far less grunty, they're relatively benign. Just imagine you had a very heavy duty light dimmer, driving some high wattage lamps in your room - do you think that a normal stereo would be completely impervious to any interference from that?

[fas42]

5 minutes ago, jabbr said:

 

This isn't true. As I mentioned above:

 

1) what about an input choke filtered power supply? How do "transient, heavy spikes of current" make it through the choke?

2) What about constant current sourced amplifiers? How would they work? Do you heard of a "cascode"?

The whole point of a "typical power supply smoothing cap" is that it is the supply current that is smoothed with respect to amplifier draw.

3) What about shunt supplies? They are also designed to supply "instantaneous spikes" of current without drawing such spikes from the mains AC.

I could go further on and on, but start by addressing the three examples

 

 

Really?

Let's start with a few very simple questions:

1) what is current in amps that the lamps use?

2) what is the maximal current in amps that the ampifiers draw? 

3) how many amps is the circuit rated for

4) at any point does a fuse blow?

 

C'mon

 

Of course one can do designs which mitigate the situation - I've come across all sorts of clever thinking which improve the behaviour; I'm commenting here on the classic power supply circuit, which is standard fare in every textbook.

 

The smoothing cap is there to try and maintain a decently stable voltage rail; heavy bass comes along and lots and lots of energy is needed by the output stage - the caps sag by a decent amount, and then the next charging pulse comes along, and depending upon the ESR of the caps and everything else a tremendous spike of current feeds that part of the circuitry - why is the standard diode bridge used a whopping, 35A rated part? ... because, it needs to be .... And the primary current reflects that draw ...

 

The point about the lamps is the transient nature of the current draw, and the number of amps involved - high current suddenly starts, and then stops - lots and lots of harmonics are generated, depending upon everything.

 

The reality is that plenty of people have found that separating the supply of mains power for the amps from the rest of the gear can make a major difference - if something works, then there is a reason.