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Old 6th October 2009, 11:53 AM   #41
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Originally Posted by john curl View Post
I think of audio as ART, with a little engineering thrown in. Yes, Jan, you probably would have found interesting seminars to attend. I met fellow audio designers that I have worked with over the past 30 years. Even some old 'enemies' where we buried the hatchet between each other, as our differences were based on incidents long ago. I got new ideas about capacitors, and was able to follow up, just today, on some of these new ideas with real cap designers.
Bob Cordell got to see that I was actually associated with a new amp, and he got to see what Jack Bybee was doing with wires. We all got to try the new exotic memory players, that attempt to fix virtually everything that we have found wrong with CD playback, and more! They sound pretty good, too. In one of the Ayre rooms, I saw the most outstanding projection video that I have ever seen in my life.
I found myself comparing notes with designers from all over the world. Most believe in differences in components to a great degree. I have little or no trouble with other audio designers at all, as we share the same design experience. Some were a little over the top, but their sound was often pretty good anyway. My only disappointment was not talking privately with Charles Hansen of Ayre. I saw him at a seminar, but he was not publicly available, to the best of my knowledge. I normally learn more from him than anyone else. I also bought an audio book called:'Get Better Sound' by Jim Smith, an audio consultant. Easy reading and open minded too, without selling anyone anything in particular. He and I essentially share the same audio philosophy, which is based on experience. I recommend it.
Well, sounds like it really was your worth John. I'm glad you enjoyed it, also the bit about burying the hatchet can only be a Good Thing.
Where did you pick up that book? The AES always have a good book store, but by this time I've got most of them already; good new ones are few and far between.

jd
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Old 6th October 2009, 01:23 PM   #42
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Originally Posted by john curl View Post
I don't know why anyone here wants to display their ignorance, what is the point?
Wires count for me, that's for sure, and we heard differences in connecting wire, when we were setting up. I had not heard either cable before, but there was a difference, and everybody heard it. We were not trying to impress customers, we were just trying to get the sound 'right' in the room, before the doors opened.
Here we go again. Same old John Curl. Anyone who does not see it exactly his way is displaying their ignorance. Anyone who questions just one aspect of cable issues is an ignorant soule who just believes in ZIP cord. No in between for John. You are either a believer of an unwashed ignoramus. John is such a believer that he blindly believes evrything that was asserted at the Nordost seminar even though he was urged to go but preferred to have a few more beers.

I was fascinated by what was said at the Nordost seminar and had many questions to better understand what they had done and were saying, but I certainly did not rule out what they were asserting. If there is something there, I want to know more about it, be able to understand how to duplicate the results, and be able to perhaps understand the cause and effect. I spoke at length with the two presenters and they were honest enough to say that these results were still a work in progress and that they had not yet drilled down to the specifics of cause and effect.

John is the one that is closed-minded and is not interested in deeply investigating anything that he already has a religious belief in. He is definitely not in a position to criticise those who ask reasonable questions in order to unederstand things better.

This industry is filled with snake oil, but that does not mean that it is all snake oil, even if we do not understand some of it. One of the fascinating things about this business is trying to navigate through the snake oild and find the good stuff. Separating it out while having an open mind is the goal. In such a morass of 50% snake oil (even John privately admits this), one who exercises some healthy skepticism and curiosity while keeping an open mind is certainly not an ignoramous. The one who blindly accepts all of the marketing cr@p at face value is the ignoramous, and the one who will forever be unable to synthesize better solutions based on knowledge and understanding as opposed to being like a monkey at a typewriter. Talk to any high-end cable vendor and he will tell you that at least half of the rest are peddling snake oil.

Cheers,
Bob
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Old 6th October 2009, 01:40 PM   #43
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Quote:
Originally Posted by john curl View Post
I think of audio as ART, with a little engineering thrown in. Yes, Jan, you probably would have found interesting seminars to attend. I met fellow audio designers that I have worked with over the past 30 years. Even some old 'enemies' where we buried the hatchet between each other, as our differences were based on incidents long ago. I got new ideas about capacitors, and was able to follow up, just today, on some of these new ideas with real cap designers.
Bob Cordell got to see that I was actually associated with a new amp, and he got to see what Jack Bybee was doing with wires. We all got to try the new exotic memory players, that attempt to fix virtually everything that we have found wrong with CD playback, and more! They sound pretty good, too. In one of the Ayre rooms, I saw the most outstanding projection video that I have ever seen in my life.
I found myself comparing notes with designers from all over the world. Most believe in differences in components to a great degree. I have little or no trouble with other audio designers at all, as we share the same design experience. Some were a little over the top, but their sound was often pretty good anyway. My only disappointment was not talking privately with Charles Hansen of Ayre. I saw him at a seminar, but he was not publicly available, to the best of my knowledge. I normally learn more from him than anyone else. I also bought an audio book called:'Get Better Sound' by Jim Smith, an audio consultant. Easy reading and open minded too, without selling anyone anything in particular. He and I essentially share the same audio philosophy, which is based on experience. I recommend it.
I enjoyed seeing John's new amp. It sounded quite good, especially given that John readily pointed out that it is aimed at the afforable end of the high-end spectrum. His amp appears to be a good implementation of a conventional Hybrid class D amp, where a class D amp drives the rails of a low-voltage class AB amp that drives the speaker output. The class AB amp thus uses far less power and at the same time is what is actually generating the final signal to be appled to the speaker. This isolates the output from the distortions and shortcomings of the class D amp that does all of the heavy listening.

The hybrid class D approach also can keep the output filter out of the direct signal path and permits the use of global negative feedback all the way from the speaker output without the phase shift of the class D output filter interfering with phase margin and loop stability. I do not know if John took advanatge of this last feature of Hybrid class D or not.

The hybrid class D approach is reminiscent of the Tecnics amplifier that used a large class B amp to drive the rails of a low-voltage class A amp. I always thought that was a cool idea.

I think John said it does about 200+ wpc. It does not have a big external heat sink, but generates enough heat to feel it with one's hand on the cover, suggesting that the small class AB amplifier is operating with a healthy quiescent bias.

Nice job, John.

Cheers,
Bob

PS: I was fortunate enough to meet Charles for the first time in person and enjoyed our brief chat. He is a very nice guy and I really enjoyed meeting him.
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Old 6th October 2009, 02:40 PM   #44
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Well Bob, I have to agree with you that the Nordost presentation was probably mostly 'snake-oil'. I had visited a previous presentation from them and thought it would be boring to go through that again. Personally, I was having fun at the bar, talking to semi-believers, to the right of me, and didn't want to disrupt our conversation.
Why I mentioned your input here, about the Nordost presentation, was that it appeared to be about the ONLY thing that you brought up here, NOTHING GOOD that you heard, or anything else significant about the show. I had heard somewhere that Nordost had actually done some measurements, so I was interested in what they found.
A personal phone conversation with Demian gave me the his update on the Nordost presentation and he concluded that you were right. Didn't I amend my input to you, once I talked to Demian?

Last edited by john curl; 6th October 2009 at 02:59 PM.
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Old 6th October 2009, 02:46 PM   #45
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You should read the short piece on Stereophile's website re the Nordost presentation at RMAF. Has anyone here ever read the Onion? It's a satirical spoof paper that writes pseudo-news stories for humorous effect. I swear you could lift that Stereophile piece verbatim, title and all, and put it in the Onion and it would look and read like it belonged there.
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Old 6th October 2009, 02:53 PM   #46
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Well, Bob, 'you can lead a horse to water, but ...' .
Actually, the amp is a bit more than what you stated, Bob, but I can't say more. What you said is just like me saying 'It was a Class AB amp'.
I'm somewhat relieved that you didn't come back when the other designer was present in the room. He would have either told you too much, or most probably kept me from trying to tell you what I could.
The 'patented' aspect of the amp has nothing to do with the switching power supplies, we could make a similar amp without them. In fact, the other designer and I discussed it, just yesterday, just to see what problems the Class D is giving us, as we had one serious complaint at the show, from a friend of mine, Ric, who works with RR. Heck, the SoundCraftsman had somewhat similar power supplies 20+ years ago. Still, the essence is in the details.
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Old 6th October 2009, 03:22 PM   #47
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Originally Posted by john curl View Post
Well Bob, I have to agree with you that the Nordost presentation was probably mostly 'snake-oil'. I had visited a previous presentation from them and thought it would be boring to go through that again. Personally, I was having fun at the bar, talking to semi-believers, to the right of me, and didn't want to disrupt our conversation.
Why I mentioned your input here, about the Nordost presentation, was that it appeared to be about the ONLY thing that you brought up here, NOTHING GOOD that you heard, or anything else significant about the show. I had heard somewhere that Nordost had actually done some measurements, so I was interested in what they found.
A personal phone conversation with Demian gave me the his update on the Nordost presentation and he concluded that you were right. Didn't I amend my input to you, once I talked to Demian?
John,

You still have not gotten it right. You need to read my post more carefully. I did not say that the Nordost thing was snake oil. I was extremely interested in it.

I also made it clear that I heard a lot of good stuff at the show. Go back and read my post again. It was a great show and very worthwhile. It was good seeing you and talking with you. The show was very worthwhile for me, even if you wrongly categorize me as a non-believer. Someday you may come to understand that there are degrees of believing. I don't subscribe to believing everything; I am a more discriminating believer; you seem to be a releatively undiscriminating believer. That does not mean that the things you believin in are not right. I hope I am making this clear. To each his own.

You put words in people's mouths, paint everyone with a broad brush, and usually hear what you expect to hear, rather than what is actually said.

Bob
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Old 6th October 2009, 03:35 PM   #48
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Originally Posted by john curl View Post
Well, Bob, 'you can lead a horse to water, but ...' .
Actually, the amp is a bit more than what you stated, Bob, but I can't say more. What you said is just like me saying 'It was a Class AB amp'.
I'm somewhat relieved that you didn't come back when the other designer was present in the room. He would have either told you too much, or most probably kept me from trying to tell you what I could.
The 'patented' aspect of the amp has nothing to do with the switching power supplies, we could make a similar amp without them. In fact, the other designer and I discussed it, just yesterday, just to see what problems the Class D is giving us, as we had one serious complaint at the show, from a friend of mine, Ric, who works with RR. Heck, the SoundCraftsman had somewhat similar power supplies 20+ years ago. Still, the essence is in the details.
First, John, I was not criticizing your amp at all. It was a nice job you did. Can't you even recognize a compliment when it is staring you in the face?

Secondly, I'm sure there is a lot more to it than what I summarized as my simplified impression of how it worked. What I described is well known and not novel or patentable. I'm sure that the patentable aspect of your design involes the devil in the details. It is easy for me to say that it is a class AB amp whose rails are driven by a class D amp, but that certainly does not say it is easy to implement in the real world. Hats off to you for making it work. It is notable that you did not dispute my basic description of the amplifier as being one where the rails of a class AB amp are driven by a class D amp.

I am sure there is some good trade secret stuff in there and maybe some patentable stuff. As you correctly said, the essence is in the details, and I am totally cool with you not wanting to discuss those. I just thought that the folks here would like to know the basics of what your amplifier was and that I liked it.

I think that there has not been as much activity on Hybrid class D because most of the good minds working on class D are too focused on getting the last bit of high efficiency out of the design rather than investing in more complexity and a bit lower efficiency to get higher audio quality. My hat is off to you for being one of the people pushing Hybrid class D as a good tradeoff for the higher-end part of the audio world.

Cheers,
Bob
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Old 6th October 2009, 03:43 PM   #49
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From the show exhibitor's perspective, things are rather different.
This is pretty much, how it goes:
First, you don't want to lug your personal hi fi system to the show, if you can avoid it. You might just try to bring your new component that you want to show, and you collaborate with others, some of whom you might not know very well, to bring the rest. For example, in our room, the speakers and the CD based music server were completely unknown to me, before the show. Still, there was as much 'money' put into that room as it would take to buy a BMW or even a cheap Mercedes, cash.
The results? OK, but not good enough. We did not get the results we wanted, even though various people spent hours setting it up, swapping components, except for the server and the amp, and 'tuning' the room. That is why we took the amp completely out of the room on Sunday, and put it in another room, with different speakers, cables, etc. but with the same brand of server. It sounded better with the other speakers. Perfect? No, but better.
One evening, we compared our amp in a third room with Class A tubes, running open loop. We lost in the comparison. My co-designer almost went nuts, because he had never 'lost' an amp comparison up to this time. He asked me repeatedly, what happened. I said, "tubes" are often more 'romantic' sounding, and in this situation, it sounded better, especially on human female voice. The system needed the 'sweetening' that their tube amp provided.
Now, how many of you, out there, work at this level? How many of you have access to a number of speakers and amps, just to compare? And finally, how many of you have 'forgiven' the flaws in your home audio system so that it sounds better to you than just about anything? The test is to get a experienced listener to listen to your hi fi, and give you an HONEST appraisal. You might be disappointed. I certainly enjoy my own home system, but I am loath to play it for anyone else. I haven't even bothered to set it up correctly, or to maintain it properly, because I have 'forgiven' its flaws, but almost everyone, in the know, virtually winces when they hear it.
That is normal. What is exceptional is when you can go into a hotel room, set up an audio system, and then WOW just about everyone who comes in the room. Nobody, in my limited experience at the show, did this, successfully, however Ayre had the best VISUAL presentation, bar none.

Last edited by john curl; 6th October 2009 at 03:46 PM.
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Old 7th October 2009, 11:44 PM   #50
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in this situation, it sounded better, especially on human female voice.

Wow. What species do you usually listen to?
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