John Curl's Blowtorch preamplifier part II

[jacco vermeulen]

Mr Wurcer, please do not feed the newbies.

 

[a.wayne]

^^

John seemed to have enjoyed his celebratory status at RMAF very much, heavily embedded in the WA room , i was told he was all smiles or was it because Sy was not there to rain on his parade ....

 

[Steve Eddy]

So what is? If the recording doesn't represent the intent of the artist, then I'm pretty sure nothing else does, either. If accurate reproduction of the recording doesn't get us closer to that intent, then what does?

EXACTLY!

Look, this is what I'm getting at. There are those whose preferences are for the most neutral, technically accurate reproduction. Which is all well and good. But some of them tend to look down their noses at those whose preferences might be for something not quite so neutral and technically accurate. And to try and justify their preference, they pull out the bit about getting closer to what "the artist intended," as if that somehow lends greater legitimacy to their preference over the preferences of certain others.

But when you examine that a bit more closely, it starts falling apart rather quickly in my opinion.

The "artist's intent" was made while listening through a number of "filters," not the least of which were the monitors used in the studio. So what you end up with encoded into the actual recording is something of an inverse transform of all those filters. So reproducing that recording with a high degree of accuracy is sort of like playing back an LP without the RIAA filter.

The old Altec 604 is rather popular among some people here. Put put a pair of those into the system of someone who goes for the most technically accurate reproduction, and they'll likely say they sound like crap and should be tossed into the nearest dumpster.

But play back some recordings that were made when those 604's were common in recording studios and I would argue that what you're listening to is closer to what "the artist intended" than with a much more technically accurate loudspeaker.

Basically what I'm saying is that "what the artist intended" is too nebulous a term to have any real meaning and I'm sick of seeing it used to browbeat those whose preferences and choices in music reproduction are different from those who prefer and choose the more technically accurate route.

I think everyone's choice is wholly legitimate for each individual and no one has any inherently "higher ground" here.

That's all I have to say.

se

 

[Jakob2]

A slight degree of humbleness often could help.

I like a word of Richard Heyser:

"One of the most belittling experiences is to deride the 'black art' of a craftsman who gets consistent results by a certain ritual which he cannot explain and then to discover that his actions in fact held a deeper technical significance than we understood at that time from our simplified model."

@ Steve Eddy,

Thanks. However I don't see any mention at all of transducers, which is what my point was focusing on.

Studio acoustics is the other part of the equation; using the same transducer without the room acoustics would not be sufficient. *

And it is still a matter of fact that different individuals exposed to exactly the same sound field can get a very different perception.

* The EBU emphasizes both, the room acoustics and the technical parameters of loudspeakers, while trying to get a better degree of accordance wrt to the subjective assesment of sound quality between broadcast units in different locations/countries.
http://tech.ebu.ch/docs/techreview/trev_274-hoeg.pdf

 

[Steve Eddy]

Studio acoustics is the other part of the equation;

Sure. But it was never my intent to cover all of the equation. I just chose monitors as a singular example to make the broader point.

se

 

[scott wurcer]

Of course it is. But for as few parts it takes the circuit is a winner.

This whole comment is strange coming from you considering the obsessive chasing of the last -130dB's What are people to think?

 

[FrankWW]

Interesting discussion. The reproduction system is a constant. As is "the intent of the artist", Even if we don't exactly know what that is.

Here is an example of an original recording. And then the same recording cleaned up to modern standards with an orchestral accompaniment.

Enrico Caruso: Giordano: Fedora - Amor Ti Vieta - YouTube
Enrico Caruso - Amor Ti Vieta (Remastered) - YouTube

So, in what fashion has the new process with the vastly changed processing changed the "artist's intent"?

[edit] Has it made it clearer or obscured it?

Even WITHIN that original context, "the intent of the artist" was not "fully represented". That was only what they signed-off on, at the time. And on a different day, their interpretation and performance would have been a little different, too. (And maybe they were even thinking that someday there would better speakers and then it would sound more like they intended.)

So what? What's your point? What's your recommendation? It's already less than perfect so it's pointless to strive for accurate reproduction?

I'm not trying to belittle your original observation, which is obviously valid, to some variable extent. I like pointing out flaws and turning rose-colored glasses brown as much as the next guy. (Although, for me, it's much more satisfying if I can then provide some solution or information that makes everything way better than before.)

I don't think that it's a significant problem. There is far more variability from other factors. We have to take whatever we can get and run with it (or not). But I still want to hear each particular recording as accurately as possible.

And it seems clear that the vast majority of what the artist chain wanted us to hear is present in every recording, almost regardless of sound quality. Maybe we can enjoy 50% of the composer's intent by hearing it rendered by a kazoo, and 75% with any real instruments, and 90% if the sound quality is high and the performers are professionals. Using a superb reproduction system could squeeze out a few percent more, which could be the difference between merely wonderful and sublime. On the other hand, acquiring the 1959 recording of David Oistrakh with the Philadelpia Orchestra, playing Tsaichovsky's Violin Concerto in D might provide a much greater improvement than any increase in system quality could, for that piece. (But I'll take both!)

With more-modern music that typically has only one performer or band that owns it or is well known for it, there is a related phenomenon. I have favorite recordings that I have heard hundreds of times. When I hear a different recording of the same song by the same performers, or a recording of a live performance of the same song by the same performers, often I don't enjoy the experience (although I was fascinated by Heart's acoustic version of "Crazy On You" from their album "The Road Home", when I first heard it). The first few times I experienced that, when I was young, it really jolted my thinking about "the artist's intent".

The passing of time, the changing of venues, everything changes what we get to hear and how we perceive it and how that makes us think and feel.

I think that maybe it all dwarfs the typical deviations due to recording studio conditions. It also dwarfs differences in our systems' reproduction accuracies, in one sense. But we can control THAT and making it better makes it better, because it gives us more information and more-accurate information.

(Or were you going to propose eq'ing based on which studio and era a recording came from? That might be interesting.)

 

[simon7000]

This whole comment is strange coming from you considering the obsessive chasing of the last -130dB's What are people to think?

I am finishing up a stadium system. The number of issues that are involved depends on the level of knowledge. The last tweak was to add a rate converter between the CD player and the mixing console. As long as the mixer did not have any Dante feeds the CD worked. But as soon as we taxed the electronic brain of the mixing console it tried to play 44,100 samples a second and left the other 3,900 dead air.

Now this system uses a 48K master clock to drive the mixing console, four wireless microphones, two announcer preamp-compressor-A/Ds and the CD player. The AES output of the console is distributed via fiber to all of the 100++ amplifiers. There is DSP on every audio channel. This includes crossovers, equalization, compression, limiting, time alignment, atmospheric loss compensation and dispersion compensation.

Adjusting these parameters takes a crew several weeks.

Designing the loudspeaker system to not only cover uniformly even with very strong winds was not enough. Maintaining direct to reflected ratios to obtain adequate speech intelligibility was a primary design issue, as was being able to get adequate volume for simple signal to noise ratio.

Overall the project took two years.

And now you ask why sometimes I find simple and well performing a pleasant change?

The results of the listening test were quite dramatic. After listening to a dozen pre-amps folks just jumped up and said "That one!"

ES

 

[31697B]

Dangers of Drinking -

Wow! What a state of confusion exists. Different goals and different reasons for those goals and different fields or categories and everything else thrown in the social mixer. Stir well and you have consumer audio.

I see some of these are at play here --->
"If you can not dazzle them with brilliance, baffle them with Blarney.' and another popular theme to jump on - "Bad decisions make good stories." And, I have to stop saying "How stupid can you be?" Because some people are taking it as a challenge.

And now I just read an article on the Dangers of Drinking. Scared the crap out of me. SO THAT'S IT ! After today, NO MORE READING !


-Richard

 

[SY]

Slightly OT question for Ed (since he mentioned Dante)- CAT5 seems to be the standard for installations. What's the limiting factor for doing things wireless?

 

[a.wayne]

Cost and signal interception/interference ............

 

[DF96]

There are those whose preferences are for the most neutral, technically accurate reproduction. Which is all well and good. But some of them tend to look down their noses at those whose preferences might be for something not quite so neutral and technically accurate. And to try and justify their preference, they pull out the bit about getting closer to what "the artist intended," as if that somehow lends greater legitimacy to their preference over the preferences of certain others.

I take your point about the studio monitors effectively creating an 'inverse filter' effect but the snag is we don't know what they were, and we don't know what effect the room itself had. To my mind the real problems arise when people try to claim that their chosen lack of neutrality is somehow more neutral than neutral, more hi-fi than transparency.

Without detailed knowledge of the filtering which is to be inverted, or the distortion which is to be post-distorted away, a return to true neutrality cannot happen so all we get is two different wiggles combining to make a more complicated wiggle. Complicated wiggles, whether in frequency response or transfer function, tend to sound worse than simple wiggles so people like me prefer to stick with the simple wiggle supplied by the artists/recording engineer.

 

[Jakob2]

How do you know if your reproduction chain produces a simple wiggle or a complicated one, if you don´t have any information about the studio/mastering situation?

 

[DF96]

I was assuming the best case. A more complex situation strengthens my argument.

 

[simon7000]

Slightly OT question for Ed (since he mentioned Dante)- CAT5 seems to be the standard for installations. What's the limiting factor for doing things wireless?

For one amplifier, reliability or interference. For many bandwidth, 1 Ghz switches are the minimum for any real system.

 

[scott wurcer]

The results of the listening test were quite dramatic. After listening to a dozen pre-amps folks just jumped up and said "That one!"

ES

Sort of obviates the fussing over resistors doesn't it? There are plenty of cases here of circuits with -70dB or worse seconds and thirds where only Resistas from the "right" factory will do. You see how hard it is to take this seriously. BTW the offset issues on that amp are very serious at 48V supply.

 

[john curl]

Thanks Wayne, who did you learn about WA from? Yes, I was 'honored' because of my 30 year old contribution to the Wilson Audio group with the Ultramaster 30 ips tape electronics that I made exactly 30 years ago. The only thing that I have designed recently that they acknowledged was my little A-21 power amp that drove their Ultra-woofers, during the demo. Everything else was tube electronics.
I find hi end audio alive and well, with plenty of engineers still buying the expensive stuff, as well as other professionals. It IS kind of expensive though, and some people assume that I can afford my own designs, well as my contemporaries, and I have to tell them that I have to design it myself, buy used, or sometimes get a gift of appreciation from a manufacturer for my earlier efforts.
Well, back to design in the next input.

 

[SY]

For one amplifier, reliability or interference. For many bandwidth, 1 Ghz switches are the minimum for any real system.

Mille grazie!

 

[john curl]

First, now I kind of understand the 'confusion' over my showing the simplified version of the Vendetta Research SCP-1 that was first built a little over 30 years ago. Erno Borbely ran an article in Vol. 6 of Jan's publication that I didn't know anything about, until I bought a copy from Jan at the RMAF on Saturday. I recommend that serious builders read that article to get even more insight and a slightly different perspective on the same phono gain stage approach.
I do not agree with everything that Erno recommended, but that is what makes audio design interesting. Please note, his design is optimized for 10ma parts, any other Idss will require you to change the other components a little, just like my designs. There is no 'free lunch' with this level of design.

 

[a.wayne]

Thanks Wayne, who did you learn about WA from? Yes, I was 'honored' because of my 30 year old contribution to the Wilson Audio group with the Ultramaster 30 ips tape electronics that I made exactly 30 years ago. The only thing that I have designed recently that they acknowledged was my little A-21 power amp that drove their Ultra-woofers, during the demo. Everything else was tube electronics.
I find hi end audio alive and well, with plenty of engineers still buying the expensive stuff, as well as other professionals. It IS kind of expensive though, and some people assume that I can afford my own designs, well as my contemporaries, and I have to tell them that I have to design it myself, buy used, or sometimes get a gift of appreciation from a manufacturer for my earlier efforts.
Well, back to design in the next input.

Many grapevines John,

It was not unexpected, considering Dave was re-releasing his tapes from your era for analog to digital transfer, so having you there Ole man was the Icing ....


Glad you enjoyed yourself ......