John Curl's Blowtorch preamplifier part II - Page 2881 - diyAudio
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Old 1st November 2012, 08:46 PM   #28801
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Christophe; it is culture-dependent, like it or not. A German guy was doing push-ups on the beach, when French guy said, "Your woman left!"
Both were right.

He is a hero to calculate 7 poles (what for?) I am too lazy, I keep things much simpler, Like he did when was not afraid to include the filter into the loop.

But may be let's ask Bruno himself? May be he meant something way different that can help us a lot?
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Old 1st November 2012, 08:47 PM   #28802
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What I heard the big Byrstons on was the Martin Logan CLX, Totem Wind, and the PMC studio speaker Bryston distributes here in North America. They can be impressive dynamically, but they are harsh and undetailed compared to Pass and Parasounds I have heard on 2 of these speakers even using a Bryston preamp and Bryston DaC / CD player. I like other amplifiers and anchovies on pizza - there is a link......

I also have Quad 63's and took the dust covers off them. They hissed every summer. I hand carried them to Huntington in the UK in the late 90's and had them totally rebuilt. Then they were too wide to sit next to the LCD TV and have been in the crawlspace for 15 years...

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Old 1st November 2012, 08:48 PM   #28803
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Maybe the solution is the audio encabulator?

Audio turboencabulator | EDN

jan
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Old 1st November 2012, 08:53 PM   #28804
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Quote:
Originally Posted by Wavebourn View Post
He is a hero to calculate 7 poles (what for?)
Standard control system theory applications. For ultimate linearity, you keep the OL gain up as high as possible for as long as possible, and then it falls off with, according to Bruno, 100dB/oct. Then (his words again) you put on the breaks just before it gets to unity gain and slow it down to 6dB/oct to keep it stable.
Lots of zeros and poles to juggle, and he does it masterly.
I have seen this kind of thing in for instance missile intercept and attitude control loops, but never in audio.

jan
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Old 1st November 2012, 09:01 PM   #28805
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A German guy was doing push-ups on the beach, when French guy said, "Your woman left!"
The French reputation is highly over-evaluated, concerning their interest to women. Lot of them have been married...
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Originally Posted by jan.didden View Post
and then it falls off with, according to Bruno, 100dB/oct.
Brrr...
http://www.youtube.com/watch?v=ytAYsn__ZZI
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Old 1st November 2012, 09:08 PM   #28806
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Quote:
Originally Posted by jan.didden View Post
Standard control system theory applications. For ultimate linearity, you keep the OL gain up as high as possible for as long as possible, and then it falls off with, according to Bruno, 100dB/oct. Then (his words again) you put on the breaks just before it gets to unity gain and slow it down to 6dB/oct to keep it stable.
Lots of zeros and poles to juggle, and he does it masterly.
I have seen this kind of thing in for instance missile intercept and attitude control loops, but never in audio.

jan
It is the limitation when you fly to the Mars, but amplifying audio? Still I wait for Bruno to explain. Thanks Jan anyway.
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Old 1st November 2012, 09:38 PM   #28807
bcarso is offline bcarso  United States
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The key to the basic UcD is a comparator with "substantially" no hysteresis and just a little delay, which along with the two poles of the basic L-C output filter and overall feedback, gives you the self-oscillation. Unlike many, the patent is fairly open to comprehension.

I think Philips (the patent holder) assumes that you will simply copy the early reference design, down to the last discrete bipolar driver transistor. I gather that BP has gone well beyond that initial design for the Hypex products.
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Old 1st November 2012, 10:41 PM   #28808
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Originally Posted by jan.didden View Post
Standard control system theory applications. For ultimate linearity, you keep the OL gain up as high as possible for as long as possible, and then it falls off with, according to Bruno, 100dB/oct. Then (his words again) you put on the breaks just before it gets to unity gain and slow it down to 6dB/oct to keep it stable.
Lots of zeros and poles to juggle, and he does it masterly.
I have seen this kind of thing in for instance missile intercept and attitude control loops, but never in audio.
Prof. Edward Cherry showed how to do this for simple (?!) amps with his NDFLs. (check out the AES library) His analysis of PA behaviour is a 'must (heavy) read'. But you don't have to go to his lengths to get substantial benefits from his insights.
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Old 1st November 2012, 11:17 PM   #28809
fas42 is online now fas42  Australia
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Some months ago I started playing with Bruno's topology in LTspice, the goal is 2.4kW into 8R, quite doable in fact. No major problems so far, but it's been pushed to the back burner, other enthusiasms and life came along, as is always the way. So, it's a round tuit for the moment ...

Frank
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Old 1st November 2012, 11:22 PM   #28810
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NDFL
National Defense Foreign Language ?
Natalie Dufty Family Law (New Zealand) ?
North Dakota Film Library (Fargo, ND) ?
Nuclear Development Field Laboratory ?

CAE (Committee for Acronym's Eradication)
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