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Old 21st January 2010, 01:29 AM   #11
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Thank you for the more thorough explanation.

Now for the 20k phono...how many regulated supplies in that bad boy?
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Old 21st January 2010, 02:05 AM   #12
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Don't know yet, just getting started.
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Old 16th February 2010, 05:17 PM   #13
mlloyd1 is offline mlloyd1  United States
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btw, some nice pics of the jc3:

Parasound Halo JC3 Phono Preamp & Atlantic Technology AT-1 - SlashGear

mlloyd1
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Old 16th February 2010, 07:39 PM   #14
AVWERK is offline AVWERK  United States
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The black 10uf cap across the AC line. Is this a Rifa PP or ?

Regards
David
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Old 16th February 2010, 07:44 PM   #15
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It doesn't matter.
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Old 21st November 2010, 02:00 AM   #16
KBK is offline KBK  Canada
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Quote:
Originally Posted by john curl View Post
It doesn't matter.


Stop it, John, yer killin' me.
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Old 21st November 2010, 02:05 AM   #17
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Shush, I am just limiting discussion on the subject.
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Old 28th December 2010, 07:26 PM   #18
kamis is offline kamis  Serbia
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Thera are enaugh information available for JC-3 so I got a whole picture about it. High resolution photos show us power supply which is not true dual mono . but only dual regulators -LM 317 AND 337 type. Even capacitor values are visible. According to detailed description on manufacturer site, each chanell have Vendetta type Norton eq. regulators. Fet helpers are constant current sources to bias op amps in class A. RIAA is of two stage type. Using one op-amp AD 797 for both MM and MC is not the best solution since this op -amp has high current noise for MM. Also, bias current is max. 2000nA which is too high for direct connection of cartridge.
Cocstruction and enclosure are to highest standard , but descrete circuits are still better.
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Old 25th March 2011, 05:19 PM   #19
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Quote:
Originally Posted by kamis View Post
Thera are enaugh information available for JC-3 so I got a whole picture about it. High resolution photos show us power supply which is not true dual mono . but only dual regulators -LM 317 AND 337 type. Even capacitor values are visible. According to detailed description on manufacturer site, each chanell have Vendetta type Norton eq. regulators. Fet helpers are constant current sources to bias op amps in class A. RIAA is of two stage type. Using one op-amp AD 797 for both MM and MC is not the best solution since this op -amp has high current noise for MM. Also, bias current is max. 2000nA which is too high for direct connection of cartridge.
Cocstruction and enclosure are to highest standard , but descrete circuits are still better.
Hi kamis,

Thanks for your comments on the JC-3. I too am curious about the design. It looks like it has been well-received.

With regard to your comments, do you mean to say that all of the gain in MC mode is achieved with a single AD 797?

Also, do you also mean to say that in MM mode the input of the AD797 is connected to the MM cartridge without something like a JFET buffer?

The quoted S/N for the JC-3 in MM mode is quite good (I think it is about 85 dB, A-weighted), but it is quoted with the MM input shorted. Any idea what it would be with the input connected to a typical MM cartridge?

Cheers,
Bob
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Old 25th March 2011, 05:37 PM   #20
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The JC-3 does NOT use an AD797.
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