John Curl's Blowtorch preamplifier part II

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PMA,
Yes, let's see any ESL panel do 116db@1watt output. Though I have heard some nice sounds out of a large electrostatic there was always something missing, and the localization of high frequencies is not one of there strong point with that much surface area. A ribbon tweeter would be preferred over a large panel in that regard and then you typically need to add a direct radiator for low bass at any real output without running out of excursion with the panels.

I can say I have enjoyed the sound of and electrostatic but it would not be my first choice.
 
PMA,
Yes, let's see any ESL panel do 116db@1watt output.

I am not sure, a colleague of mine used ESL panels (full range) at a high end exhibition and he had to check and monitor output level of the power amplifier very carefully, otherwise the resulting distortion, after exceeding certain not very high SPL level, was horrible.
 
I thought you said you bought it used. Somebody took you for a ride John.;)



Seriously though, you really think defects caused by a hard physical process on the edge of a thin film has anything to do with how a 12 guage ETP copper wire conducts electricity?

I've got a bridge to sell you.

jn
I am interested in what less than 99.999% look like in relationship to the thin film and round wire or flat cable highly annealed as well as not. Data with out context is of less value . Example years ago the drug company would advertise the amount they spent on research in the billions dollars . However they spent 1.5 times that much on advertising .
That effect on the edge may relate in some way to the processing done to copper that is bonded to pc boards . But those effects of treating copper start to show up in the 4ghz plus range. Context helps.
 
Ah, you mean Merhaut's electrostatic speaker. Prof. Merhaut was my teacher at Prague Institute of Technology, I studied electroacoustics. He was the inventor of the speaker shown. The speaker had range 1kHz - 20kHz (above). It was the only speaker I know with non- oscillatory impulse response. 10 - 20us rectangular impulse was a rectangular impulse with rounded edges ...
It is a differential electrostatic driver, membrane is heavily loaded so that the response is extremely flat and step response is without overshoots. It was used as midrange and tweeter, in one driver.

http://www.google.com/patents/US3590169
 
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It still isnt lower over the whole freq range as the QUADs.

Actually, I like horns.... except for the bass. I had a three-way all JBL horn system as my first high-end system. The new QUADs are not directional.... the new QUADs are more fig-8 and omni-directional at all freqs. Horns ability to shape the dispersion or polar pattern is a plus in some cases. But for a full range driver with good spl and very flat freq response and very low distortion -- taking everything into consideration (and no biamping/xover) -- the newer QUADs are a great tool or instrument as well as accurate music reproducer.

I use them for evaluating other gear because they are so accurate and not a large producer of distortion. If you play the QUADs at 75-80dB spl for testing use, their thd is even lower. Great tool for everything. But I do have to augment the strength and dept of the bass to listen to my kinda music. I am trying to keep the extension/power drivers thd as low as possible. Something that would be totally impracticle for a bass horn in my house.

Point being: Low speaker distortion helps a lot to hear other components distortion.


-RM
 
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JN,
When I come across it in my storage I have an old metal belt driven watchmakers lathe you could have. Don't know when I will see it but when I do it is yours. I gave an entire watch and clockmaker's tool set to a museum somewhere in Santa Barbara, CA. I have a nice grandfather clock I need to fix, haven't worked on anything like it but used to fix pocket watches when I was much younger.

Appreciate the offer. Certainly will take you up on your kindness.

jn
 
It did not happen.... I could see down to a cluster of atoms -- a molecule !

The sample was coated (one molecule thick) with various pure metals for various reasons and materials being observed. Gold was one of them.


The key, I found, much to the Chemists delight, was the zero offset in the direct coupled amps needed to be rezeroed from time to time (I had not invented the concept of dc-servo those circuit, yet). So tell your tech support to dc zero the thing's every amp stage. Have them make it a regular scheduled part of a calibration process. That alone should be good for a salary raise. :)


THx-RNMarsh

They have a nano center here with all the bells and whistles. SEM's, TEM's, STEM'S, all kinds of acronyms..I gave up understanding that tech. Now somebody watches electrons???

sheeesh..

jn
 
Hey scott, did that resistor find any use?

I'm workin the next one in .092 brass with real leads this time.

Man, I can't believe the '629 with 270 volts common mode capability. I wouldn't have expected an on chip R to do that.

jn

Still doing some construction in the mancave, trimmed out the staircase for carpet last weekend. That part is neat, I think the DS shows how little thermal distortion there is too. They make it trivial to monitor supply current sense resistors even off of large supplies or output stage error voltage at full output even at 100V rms!
 
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