DIY progress report

Professional

To GRollins : I have not any ilusions about this word and about your conclusion in mostly cases I agree. But only a few remarks. I never heard any Threshold, but in many times I was read about this schematic. Some circuit connection can be in principle good, but must be also good " tuned ". If manufacturer don't do it, product can be wrong, although first idea was good, what is maybe case of Stasis. In our coutry I was many times wrote some tests to the hifi magazines and I heard many amps without necessity to buy, so I mean, that my conclusion was objective. Many years I was building amps for musicians and sound of realy instruments I have very well " in my ears ". Problem of the most listeners is, that they don't compare sound of apparatus with real sound, but with another apparatus. I am, as designer of amps, very sensitive to the any distortion, which I hear thrue any apparatus and I must say, that absolutely most of them is in this case wrong, but you can tell it only if is it compared with live music. By many manufacturers is distortion called as " musical sound ", and by this words I am nearly to the madness. Many listeners belive in it, but I say it is only incompetence of manufacturers do apparatus with low distortion. I hear it and it is main for me. Last good amp built by Hafler was DH - 220, which was designed by Erno Borbelly. In this time is ideal for me Halcro, which I don't hear, but I saw patent and it is very good - my feeling of designer say, that must be excelent . I have many CD's Telarc and I must say, that there is not any corelation between qality of soud and amps used in studio and it is my answer to your question.
 
Picasso

Mr. Pass, thanks you for your sincerely answer, but I look on this from other side : amplifier is not musician instrument and distortion isn't written on partiture. I am much more iritated, if I hear clear music and I must not damn any manufacturer for bad work. Impressions I can made in my head and I can't do it by any amp - but I envy your peace of mind.
 
Ah Mr Pass. I share your views. If your not a slave to someone who tells you what to do , do what you like and damn the fugging reviewers. I saw the cover and read the review, but not the lab measurements.
I also read the halcrow (lower case intended). You'ld think these guys messed their shorts. And if they compaired your amp to the halcro, that's high praise. (I think the full page adds helped make their bass sound a little tighter)
Do what makes you happy. (like giving us scematics and assistance) Don't try to p!ss these people off. A positive review could only help sales and a negative review could only hurt, and I don't totally trust that their opinion of you would have no impact on what they "hear". I'm very happy that that is not your greatest concern. But I would try to get to the bottom of the power shortage and get it straight with them. I've seen quite a few manufacturers get a second shot after sample units malfunctioned.

PS Is takes too much creativity to get profanities past these filters

PSS I'm sure you already knew all of this, I'm only complementing your attitude towards life. I converted to your school of thought as a semi young fart
 
The one and only
Joined 2001
Paid Member
Brian Donaldson said:
Don't try to p!ss these people off. A positive review could only help sales and a negative review could only hurt, and I don't totally trust that their opinion of you would have no impact on what they "hear". I'm very happy that that is not your greatest concern. But I would try to get to the bottom of the power shortage and get it straight with them. I've seen quite a few manufacturers get a second shot after sample units malfunctioned.
 
The one and only
Joined 2001
Paid Member
After more than 30 years of dealing in and with the industry,
you get to know who's who, and what's important.

The amplifiers from Stereophile went out on loan after return
from the review, and are due back, so we will see what may have
happened. My own attitude is: somebody made a mistake
somewhere, and this sort of thing occurs, particularly with
review units. The important thing is that the customer gets
his expectations met, and that is the real basis of the credibility
of a company.

The first product I ever made, the 800A got a definitively
sh*tty review from Audio Critic, to the point I considered that we
were being called fraudulent. The second top-of-the-line
amplifier, the Stasis 1, was shat upon royally by Harry Pearson
himself, who after several pages of commenting on the decoding
of surface noise, simply announced that he didn't like the amp.

Julian Hirsch gave the Stasis 3 probably the worst
review ever seen in the pages of Stereo Review (and I'm really
not kidding) and concluded that it was not operational. The
initial reviews of the 2nd generation of Stasis amps did not
get particularly good press, and you might recall that even the
Alephs have their share of bad reviews.

I remember Roy Scheider in "All That Jazz" saying "I wonder
if Stanley Kubrick has days like this". Of course he did.

It is not a matter of worrying about offending a magazine by
complaining, nor is it an advertising issue. Stereophile, and
John Atkinson in particular, have gone out of their way
historically to be good to us. And they are not stupid guys.

I still consider this a good review, and if the amp didn't meet
power spec, then it will sound even better when we fix it. In
the meantime, I continue to pay taxes.

:cool:
 
I believe some here are saying that simple, analogue circuits cannot deliver the lowest possible distortion. On this basis - the objective one - the Halcro from Bruce Candy rules.

However, NP hints at something other than clinical accuracy. He opines that what sounds good to a distortion analyser might not register happiness in your ears. I agree with this.

I also feel that just as a racing GP motorcycle has to be 'tuned' in engine and chassis to the track and the rider, amplifiers should be 'voiced' to deliver the most sympathetic treatment of music to the listener. This comes down to topology, operating point, layout, and component choice - and not necessarily in that order.

Many here can state with veracity that they can design an amp of unrelenting complexity which measures uncommonly well, and sounds terrible. It will literally photocopy the music, and present the listener with an etched, accurate but astringent sound. But NP can do an impressionist amp, something sympatico with the music. That's also the choice I make these days. It is trite (but true!) that we all listen to music to tickle our souls. And the nasty sounds of clinical electronics are not conducive to relaying the emotional communication of the composer and the musicians, and nowhere is this more apparent than with reproductions of the human voice. As time passes, I hope that the emotional sterility of many of our modern amps, particularly the PWM types, gives way to something which plays music....

Cheers,

Hugh
 
Back To The Future............

Nelson Pass said:
Very cool. Where do I put the blue light? ;)
Pssssst, Blue led's are already becoming passe.
The latest Nokia mobile phones have white keypad led's - these are way cooler - check them out.
Even more modern colours !


Regards, Eric.

A hire company friend commented to me the other day that PAR-64 stage cans are the future, because they are included in all classic science fiction movies.
 
specs vs sound

I haven't heard any Pass Labs product "directly" so far. But maybe there is a chance do so some day since the Swiss sales rep isn't too far away from where I work.

But I have an interesing CD that came with a German HiFi mag.

They made comparison recordings of different equipment. They simply made a dummy head recording in their acoustically treated listening room (the speaker was a JM-LAB Mezzo Utopia in all cases). The CD was meant to be played back through headphones. Since I don't have good headphones I tried it through my speakers.

The outcome was quite astonishing. You could really hear the small but clear differences that way.

The warmest sound came from a SET monster called Double Kronzilla. The coldest but most precise sound came from a hybrid switching/linear amp made by Audio Physic.
Inbetween there was a Pass-Labs XA600. It's mids and highs were smooth and it's bass was quite special. It reminded me of a "gentle giant" who knows how much power (grip ?) he could apply but does so with care.
Since there is no perfect amp (and I doubt that there will ever be one) it's all a matter of taste. I by myself could definitely live with the XA600's sound.

Regards

Charles
 
Re: specs vs sound

phase_accurate said:
I haven't heard any Pass Labs product "directly" so far. But maybe there is a chance do so some day since the Swiss sales rep isn't too far away from where I work.

But I have an interesing CD that came with a German HiFi mag.

They made comparison recordings of different equipment. They simply made a dummy head recording in their acoustically treated listening room (the speaker was a JM-LAB Mezzo Utopia in all cases). The CD was meant to be played back through headphones. Since I don't have good headphones I tried it through my speakers.

The outcome was quite astonishing. You could really hear the small but clear differences that way.

The warmest sound came from a SET monster called Double Kronzilla. The coldest but most precise sound came from a hybrid switching/linear amp made by Audio Physic.
Inbetween there was a Pass-Labs XA600. It's mids and highs were smooth and it's bass was quite special. It reminded me of a "gentle giant" who knows how much power (grip ?) he could apply but does so with care.
Since there is no perfect amp (and I doubt that there will ever be one) it's all a matter of taste. I by myself could definitely live with the XA600's sound.

Regards

Charles

XA600 or X600?
 
Nelson Pass said:
I don't mind. Extraneous posts give the illusion of progress.


Sometimes progress is not a matter of moving forward, occasionally we need to look back and see if we took a wrong turn somewhere. A few examples might be:

Abandoning Vinyl recordings
Thinking we could improve on a good valve
Releasing the atomic genie
Trying to improve on a Pass design.

Anthony