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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 31st October 2012, 10:47 PM   #28751
scott wurcer is offline scott wurcer  United States
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Originally Posted by john curl View Post
Well, we are at stage 2: 'It exists, but it is not important.' '-)
Even Ron points out that video designers have worried about this for decades, no one ever said it doesn't exist. When flesh is green people complain, since the results for audio seem in one sense flipped it's anyone's guess how it matters.
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Old 31st October 2012, 10:56 PM   #28752
Esperado is offline Esperado  France
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Is the Ron's paper available somewhere for free ?
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Old 31st October 2012, 11:06 PM   #28753
kgrlee is offline kgrlee
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Out of all that, the only thing I came away with was greater respect for the Constant Charge Electrostatic speaker .. for bass .. unfortunately its mid & treble hasn't the potential to topple Rice & Kellog's invention.
Well, you threw a bomb here. This is contrary to all I have heard and read. Can you put some more words on this?
Electrostatics and Isodynamics need a supporting structure. On the ESL, this can be made part of the acoustic system. More difficult for Isodynamics. The rare-earth magnets allowed this to be smaller so made them viable though it is still a problem. I'll discuss the ESL-63 as IMHO, it is the best Electrostatic.

I bought one of the first ESL-63s and discussed it at length with Peter Walker. It has probably the best Delayed Resonance Curve of any speaker I've seen ... up to about 1kHz.

AES E-Library Analogue Loudspeaker Measurement with -3-D- Display We called these PAFplots after Peter Fryer as opposed to the CDS KEFplots which are now a 'feature' of all fancy acoustic measurement packages. KEFplots have no resolution below about 1kHz

It's performance above that isn't bad but the contrast with lower frequencies is so marked that it sticks out in a Blind Listening Test.

It's caused by the dust covers without which the speaker lasts about 3 mths. The wonderful looking curves for the ESL-63 in their AES paper were done without dust covers.
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Old 31st October 2012, 11:26 PM   #28754
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
You can put dust absorbers next to the speakers, like Chizhevsky lamps that will attract all garbage particles and emit good for health ions.

PS: my line arrays in walls, looking like picture frames, deserve high WAF number, and work almost 3 years without any maintenance. An array of light cones each driven by small powerful motor, almost like isodynamics. You can't repair a peace of an isodynamic speaker, but you can replace one of failed drivers in an array.
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Old 1st November 2012, 12:14 AM   #28755
kgrlee is offline kgrlee
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You can put dust absorbers next to the speakers, like Chizhevsky lamps that will attract all garbage particles and emit good for health ions.
ESL-63 without dust covers are very efficient dust absorbers, in fact very similar to your Chizhevsky lamps.

If you don't mind sending your ESL-63 for factory re-furbishment every 3 mths, I recommend you try them w/o dustcovers. But please don't wait until they arc over before you do that or your bill will be somewhat greater.

If you live in the UK, your 3 mth service is probably no more expensive than NOS Mullard EL34s or Gold Lion KT88s for your amp.
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Old 1st November 2012, 12:50 AM   #28756
john curl is offline john curl  United States
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What did I say? That FM distortion is the ONLY important distortion left? Seems to me that xover distortion is what is most audible today. Today, I am working with a design that has a 350 ohm load, and the part is rated for 600 ohms (nominally). Can't measure much, anyone think I might have a problem, subjectively? Me, being me, I am concerned. Don't worry Scott, your op amp is not under consideration, here or in the JC-3.
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Old 1st November 2012, 01:04 AM   #28757
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
Are you kidding? I said, next to the speaker! I can provide Chizhevsky lamps cheaper than service of your speakers. And I can add some knobs, to vary garbage attraction parameters.
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Old 1st November 2012, 01:13 AM   #28758
Esperado is offline Esperado  France
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Originally Posted by john curl View Post
Seems to me that xover distortion is what is most audible today.
On my personal power amp (4HEXFETS), and from an absolute subjective point of view (listening feelings), there is an optimal biasing around 150mA for each FET. If i increase bias (less theoretical crossover distortion), sound is not so good. Any explanation ?
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Old 1st November 2012, 01:21 AM   #28759
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
Xover distortion can be tolerated if they are the way under the rug. But the level under the rug is the problem, so it is better to eliminate them principally to avoid all arguments at once.
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Old 1st November 2012, 02:21 AM   #28760
fas42 is offline fas42  Australia
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Overall, audible non-linear system distortion is still the answer. It obviously exists, otherwise every system would sound the same as the next. If you want to get fussy, throw in a decent DSP to guarantee that the linear distortion is absolutely minimal, but .... still they differ!!

The final frontier ...

Frank
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