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John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
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Old 20th June 2018, 06:58 PM   #5871
anatech is offline anatech  Canada
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John Curl's Blowtorch preamplifier part III
Hi Richard,
Had I the capital, I would be in line.

-Chris
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Old 20th June 2018, 07:48 PM   #5872
ticknpop is offline ticknpop  Canada
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John Curl's Blowtorch preamplifier part III
Chris, Just behind me.
100db/1 watt/4 ohms is about 125 db allowing for some dynamic thermal compression - just what I need in the shop. Oh forgot to add 3 or 4 db for 4 speakers. Next falls diy meet we can all stand outside
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Old 20th June 2018, 09:41 PM   #5873
Mark Johnson is offline Mark Johnson  United States
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John Curl's Blowtorch preamplifier part III
Default Found in Stereophile, July/August 2018

bottom of page 8 (multi page Table Of Contents)

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Old 20th June 2018, 09:57 PM   #5874
Speedskater is offline Speedskater  United States
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Nothing like that in my print copy.
Stereophile, July 2018 Vol. 41 No. 7
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Old 20th June 2018, 09:58 PM   #5875
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not much came up...?
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Old 20th June 2018, 10:04 PM   #5876
Speedskater is offline Speedskater  United States
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Just found that Parasound review in:
The Absolute Sound
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Old 20th June 2018, 10:11 PM   #5877
Mark Johnson is offline Mark Johnson  United States
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John Curl's Blowtorch preamplifier part III
Oops, yer right. The Absolute Sound (not Stereophile!), July/August 2018, Issue 284. Sorry for the error.

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Old 20th June 2018, 10:14 PM   #5878
billshurv is offline billshurv  United Kingdom
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John Curl's Blowtorch preamplifier part III
Quote:
Originally Posted by RNMarsh View Post
<20-30dB is low, 100+ is high. And what dB's is a two opamp composite ?


THx-RNMarsh

I would argue by audio standards 6dB is low 20-35 is normal anything over 50 is high but we are close enough to agreement.


Had a furtle and found the published loop gains. 225dB at DC, 100dB at 1kHz and 49dB at 20kHz .
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Old 21st June 2018, 12:30 AM   #5879
miklos is offline miklos  Hungary
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Quote:
Originally Posted by gpapag View Post
Some old tests with back to back isolation transformers (non shielded).
The “Live Probe” schematic is from a “Wireless World” article (sorry, I can’t find year/volume number/author)

George
That is a good way to measure what's getting out of the equipment, what's getting in you can directly measure on the secondary side of the transformer.
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Old 21st June 2018, 01:53 AM   #5880
RNMarsh is offline RNMarsh  United States
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John Curl's Blowtorch preamplifier part III
I use a tiny inductive pick up. calibrated. But relative numbers are OK for this purpose.... make your own.

A tiny video recording/playback head works well. Get a used/broken video VHS machine and take the head out and use it into wide band amp, scope, sensitive VM etc. Moving the head in close proxy to a wire will pick up the signal in that wire.


-RNM

Last edited by RNMarsh; 21st June 2018 at 01:58 AM.
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