John Curl's Blowtorch preamplifier part II - Page 4053 - diyAudio
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Old 21st June 2013, 01:52 PM   #40521
SY is offline SY  United States
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Quote:
Originally Posted by marce View Post
I was wondering while doing some really small layouts (silly small, to go in cables) whether there would be any mileage in having some amplification in a turntables head shell to process the signal as close to the cartridge as possible and thus transmit a stronger signal to the pre-amp.
This was done back in the early '80s. I worked with Murray Zeligman to develop a "Headamp in a Headshell" for Dynavector, who was marketing a line of low output MCs, as well as a tonearm. Remote powered, CM860 FETs. Dynavector didn't end up using it, but it was sold for a little while by the late, lamented Audio Dimensions.
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Old 21st June 2013, 02:26 PM   #40522
marce is offline marce  United Kingdom
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But with modern packaging and hopefully some improvements in op-amps etc would it be worth some thought. Just curious, as I said I'm doing some silly small layout at the moment, 10 layer HDI, very weight conscious, so I was pondering the possibility of what circuitry you could get in a head shell. Also the evolution of sensors for engines and similar, and how they have gone from dumb basic transducers, to remote intelligent units connected by the CAN bus.
Cheers.
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Old 21st June 2013, 03:01 PM   #40523
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It's very do-able (our early effort worked very well) from a technical standpoint. The problem is marketing it in the fashion niche- there's an analogy to active speakers.
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Old 21st June 2013, 04:32 PM   #40524
marce is offline marce  United Kingdom
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Yes, I was thinking it wouldn't be a big commercial success, but as a DIY experiment It may be interesting.
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Old 21st June 2013, 06:04 PM   #40525
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Quote:
Originally Posted by scott wurcer View Post
What did he think of just intonation? Harry Partch?
Having grown up with a piano, he imagined piano (i.e., equal temperament) pitch to be perfect. But in his defense he was about 13 during this phase, and to his credit it didn't last very long. I ran into him last at a Hear Now "festival" in Venice CA, which he'd had a hand in organizing. My friend Byron Adams refers to the folks around that group as "the avant-garde ghetto" At one of the concerts I heard a violin solo that involved so much mistreatment of the instrument that I whispered to my friend Ursula that I almost expected the performer to set fire to it, a la Jimi Hendrix. The audience was wildly enthusiastic. Come to think of it, that was the last of their events I attended.

Last edited by bcarso; 21st June 2013 at 06:10 PM. Reason: equal temperament
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Old 21st June 2013, 06:09 PM   #40526
bcarso is offline bcarso  United States
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Originally Posted by SY View Post
It's very do-able (our early effort worked very well) from a technical standpoint. The problem is marketing it in the fashion niche- there's an analogy to active speakers.
That's astute --- no fun if the buyer can't substitute preamps.

When I listened, circa 1977, to music from various sources at his house, then in Tarzana, Keith Johnson was using a modified AR turntable, that ancient springy one, and had at least moved his preamp to the body of the 'table "where it belongs!" as he said when I asked about the holes in the base.
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Old 21st June 2013, 06:27 PM   #40527
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Well guys, I have been complaining about excessive distortion in hi K ceramic caps for the last 39 years. Showed measurement in print in 1978. It is a wonderful thing the EDN 'exposes' this problem to today's engineering audience.
Of course, NPO is better, and even very linear, but how about DA? No thanks, I will stick to polystyrene when I can.

Last edited by john curl; 21st June 2013 at 06:37 PM.
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Old 21st June 2013, 06:51 PM   #40528
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Originally Posted by bcarso View Post
That's astute --- no fun if the buyer can't substitute preamps.
He's also committed to one tonearm. Fashion audio customers hate not being able to mix and match and swap frequently.
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Old 21st June 2013, 08:01 PM   #40529
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Default Audio Dimensions memories

Always liked building phono stage in turntable base, also built one with fets in the headshell when I worked at Audio Dimensions in mid seventies but Ike wasn't interested , when I used current source plate loads and leds in cathode he thought I was crazy until I played it for him, then published it in The Update along with my current source diff amp front ends for Dyna tube power amps.
Lost touch with ADI when I was hired my Mike Elliot to work on Hybrid Class A amplifier and IRS speaker system at Infinity with Bascomb King. Never heard what happened with ADI but ran in to co-founder Roger Stovold at Newport show a few weeks ago after 35 years but he had left there before I did , never heard anything about Ike since I left.
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Old 21st June 2013, 08:05 PM   #40530
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Ike moved to Baltimore and got out of audio completely. From what I understand through some mutual friends, he developed hearing problems as well, so refocused his efforts into editing and publishing. Nice guy, he's missed.

I still have a bunch of my Updates. I sadly lost the one with the articles about the no-holds-barred preamp and room heater OTL amp that Murray and I built.
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