Parasound JC3 Phono

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
if parasound hasn't announced "officially" announced it as released yet, john probably can't say much. you'll probably get some good info if you send a note to parasound and say you "heard about it on the stereophile website and can't wait to get one, so please tell me more about it."

:)

mlloyd1
 
I should not jump on you Chris, I don't necessarily like the $2000 price tag either. It was designed to be the highest quality phono stage on a few square inches of circuit board that was supposed to mount INSIDE the JC-2, rather than a fancy, very nice external box. Things got out of hand.
 
John,

I was offended because I gave both you and Joachim a compliment in the body of my post. I didn't know what caused the backlash. I wasn't trying to be snarky about 2k for a phono stage and was quite sure that there would be money left over for a decent supply and good discrete circuit after the box was paid for. I sold Parasound many years ago, (though they were your circuits), and was always impressed with the sound and build quality that they were able to deliver considering the prices. I REALLY do thank you for your work in this industry and was very excited about a new Curl phono stage having heard different iterations of the Vendetta over my years selling hifi.

Regards,

Chris
 
Chris, what you don't understand is that I HAVE designed discrete phono stages for Parasound, years ago, but they didn't go through with making them.
This design was really for a small insert board per channel for the JC-2. Unfortunately, it 'grew up' into being more than what it was originally designed to do. The original discrete design worked fine, BUT NOW the jfets it used are too hard, and expensive, to get, so it is a lost cause.
You just reminded me of the painful reality of what it costs to make things like this. My next discrete phono stage will cost more than 10 times this unit, and I cannot even conceive of making a unit less than 3 times the cost of the JC-3 in my lifetime. If the insides of this unit were packaged more cost effectively, I would have been more comfortable, as it then might have cost $1000 or so. However, marketing disagreed. Sorry if I snapped at you. It is really the situation that I am not happy with.
 
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.
 
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
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.