so, being of the curious type... I presume just about everyone has read Jan's 'zine?
That article a while back on high performance regulators, recall that?
Why would anyone need or want regulation of that quality and caliber?
Could anyone possibly hear a difference between any one of those tested?
I presume it is only an exercise in engineering?
"...curiouser and curiouser said Alice..."
That article a while back on high performance regulators, recall that?
Why would anyone need or want regulation of that quality and caliber?
Could anyone possibly hear a difference between any one of those tested?
I presume it is only an exercise in engineering?
"...curiouser and curiouser said Alice..."
voltage regulators redux
There is an audiophile conceit that circuits with poorer PSR must be sacrificing something in terms of other performance measures. This attitude dovetails into one of the other favorite hobby horses, that complexity per se is bad.
IMO neither of these notions taken at face value is correct.
But once they are in play, it opens the door to better and better power supplies---and more of them, one per stage etc.
What is missed so far afaik, except in a few power amps, is the notion of signal-driven regulators, a sort of feedforward so that the response delay associated with regulation is circumvented. Oddly I presented this idea in another forum some years ago, to have one guy say that a shunt regulator already accomplished this. Nope.
There is an audiophile conceit that circuits with poorer PSR must be sacrificing something in terms of other performance measures. This attitude dovetails into one of the other favorite hobby horses, that complexity per se is bad.
IMO neither of these notions taken at face value is correct.
But once they are in play, it opens the door to better and better power supplies---and more of them, one per stage etc.
What is missed so far afaik, except in a few power amps, is the notion of signal-driven regulators, a sort of feedforward so that the response delay associated with regulation is circumvented. Oddly I presented this idea in another forum some years ago, to have one guy say that a shunt regulator already accomplished this. Nope.
Or sometimes the opposite- see, for example, Allen Wright's preamps, which had close to zero PSR. The story he was selling there was that the best topologies have the worst PSR, so it was important to have very complex supplies to make up for this deficiency. Sum total was, in fact, very high performance at this design extremum. My designs tend to go in the other direction (high PSR, simple supplies), demonstrating again that the concept of One Right Answer is somewhat ridiculous.
I may be missing something here but when the sound of resistors, caps even cables is discussed how can dirty contacts be tolerated or do the basics get fluffed over by the more important esoteric quantum supposedly sound changing beliefs... The mundane being ignored such as cleaning contacts.
Nice to see again that NO evidence wot soever for cable directivity has been put forward by the believers... same again next year chaps.
Nice to see again that NO evidence wot soever for cable directivity has been put forward by the believers... same again next year chaps.
Why do universities lecture on stuff that makes your head hurt, if one ends up frying burgers at McD.
Some more discussion of contact rectification in this pdf: http://www.tek.com/sites/tek.com/files/media/document/resources/Instrument_Techniques.pdf on page 4 of 5.
Other old discussion here:
http://nvlpubs.nist.gov/nistpubs/bulletin/05/nbsbulletinv5n1p133_A2b.pdf
Other old discussion here:
http://nvlpubs.nist.gov/nistpubs/bulletin/05/nbsbulletinv5n1p133_A2b.pdf
All good, and good on you for geting hold of one of these comparators.
We can all learn from this.
The oft quoted 'audio memory' is a factor here, ie fast/immediate switching can indeed be very useful for increasing discrimination.
See next paragraph.
No surprise. All loudspeakers of course have their stated frequency response characteristic but can be wildly dependent on the 'upstream' amplifier LF/HF output impedance characteristics, and the loudspeaker connection cable DC/frequency dependent characteristics.
Add to this differing sensitivity characteristics and dynamic characteristics, it is nigh on impossible to level match two sets of loudspeakers.
The best you can hope for is 'similar' levels on a particular programme content, change the programme and you will very likely need to change A/B levels.
Ok, so now down to business.
This Van Alstine ABX box seems to have become a defacto 'standard', and at the $999 price is accessible to many, organisations and individuals all, so far so good.
Mr VA is not making a whole lot of cash out of building these, more it seems he is making a stirling effort to build a 'decent' ABX Box for all, therefore he shall not/must not be vilified.
So lets have a really close look at the internals.
Yes, this 'individual' circuit path level control is mandatory.
So referring to the second block diagram and the above description it seems that 10K series resistance is added to each preamp/loop feed....Hmmm.
Hmmm.
So Mr VA, respectfully a very nice try but fundamentally flawed for discriminating fine differences because of the confounders outlined above.
I note also that there are no IMP/FR/SNR/THD/IMD specs for the controlled line level throughput.
Insertion of this ABX box is ipso facto too far removed from individual system testing, and from the lack of performance data available cannot be regarded as providing valid test results.
I note also that the proponents of ABX results do not quote the test conditions.
To ABX proponents, without full ABX test system disclosure.....
Dan.
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Surely there is no audible difference between these high performance regulators, yes? Regardless of circuit. Measurements sure, but audible?
Why would you say that?
Bear, I hear what you are saying on your website, yes it's all about clarity.Surely there is no audible difference between these high performance regulators, yes? Regardless of circuit. Measurements sure, but audible?
It's not so much about the absolute level of the resultant system noise as the subjective nature of the resultant system noise.
But you knew that already.
Dan.
Surprise, surprise, surprise! Old yes.
These references mention things like point contact behavior of exotic alloys, NON-Ohmic contact, etc. Non-Ohmic means a complete interruption of normal metal to metal mechanical contact which is Ohmic. Yes connectors corrode, for audio simple regular cleaning if one insists on cheap base metal connectors is sufficient.
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Answer a question with a question. Very good.
I put forth a question, I'd like to know what everyone thinks on this.
Audible? Not Audible?
I'm not taking a position, trying to learn from those who have experience/expertise in these matters.
So what's your opinion/position SY, are you going to say?
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