Parasound JC-2 power supply regulators schematic is probably trade secret , since Mr. Curl does not wish to show it to us. Is it shunt or series, feedback or open loop, or multiple stage like Blowtorch PS ?
Relays, even the most expensive types are worse than extended shaft rotary switches. They have some contact segments riveted at low forces which is bad for low level details. I destroyed some to see construction.
Relays, even the most expensive types are worse than extended shaft rotary switches. They have some contact segments riveted at low forces which is bad for low level details. I destroyed some to see construction.
Expert or not, I can hear a clear difference between good and bad contacts.I am very experienced builder and listener . I have been using J-Fet complemetary, dual complementary electronic , similar to your favorite circuits, for over twenty years. I opened the same type of relays which is used in JC-2 , and I will repeat: two contact segments ( in the signal path) are riveted -crimped to pins base with minimal force. So we have good quality , direct gold plated , pure copper , firm gripping RCA sockets and at the other end two loose series contacts . Siemens relays are much better made than Omron with a firmer contact, but not ideal. Compared to rotary switches , relays are not self cleaning. According to Omron app. note, relays should be tested periodically for contact resistence! Very, very practical.
So you Mr. Curl should have more respect to all forum members. You do not know who is hiding between Internet nicknames.
You have tendency to discourage potential builders from building some of your designs with argument: you are poor amateurs, you have no enough knowledge etc. But I as a amateur, built Vendetta second stage in two days.
It works perfectly. A croatian guy, audio amateur built the closest known Blowtorch clone. Do you remember that, you were very nervous seeing his creation. Parasound JC-3 is too simple for experienced builders. It is type of circuit for books titled something like "IC op-amps basics"
So you Mr. Curl should have more respect to all forum members. You do not know who is hiding between Internet nicknames.
You have tendency to discourage potential builders from building some of your designs with argument: you are poor amateurs, you have no enough knowledge etc. But I as a amateur, built Vendetta second stage in two days.
It works perfectly. A croatian guy, audio amateur built the closest known Blowtorch clone. Do you remember that, you were very nervous seeing his creation. Parasound JC-3 is too simple for experienced builders. It is type of circuit for books titled something like "IC op-amps basics"
These types of construction defects are part of the "mystery" of good vs. poor sound - once you really start to investigate areas of the audio path generally ignored you discover all sorts of sillinesses. Like the typical RCA socket. And, once you eradicate or bypass all the poor quality implementation elements you get premium sound -- there is no real "magic" in the game, just constant application of one's noodle ...
Kamis, you do not contradict me, however, you contradict so many others who have accused me for NOT using relays in the CTC Blowtorch. You see, I basically agree with YOU, but relays are NOT all the same, and many are pretty good, not great, mind you, but pretty good, and they are often necessary for remote controlled applications, at least at a reasonable price. I make preamps both ways, always have, always will.
You know, everyone, you just can't please EVERYBODY. I put up an early incarnation of the JC-3 phono stage here, and all I got was criticism.
I put up a middle incarnation of the JC-2 here, and I get confusion, and criticism for using relays for the MULTIPLE functions that I am asked to do.
Still others will chide me for using telecom relays when I should make do with reed relays, or something else. '-)
I put up a middle incarnation of the JC-2 here, and I get confusion, and criticism for using relays for the MULTIPLE functions that I am asked to do.
Still others will chide me for using telecom relays when I should make do with reed relays, or something else. '-)
Well, it's certainly an interesting circuit, and surprising in lots of ways. The VAS stage isn't degenerated and operates into high Z, so open loop gain should be healthy, but there's no obvious dominant pole C needed, just the RC pair at VAS input, applied differentially (often a recipe for oscillation in amateur hands). The classic JC boxer input is fully floating, including loop feedback, yet the two output polarities have slightly different output levels, presumably greater than resistor tolerances could account for. And most curious of all is location of R65, but that could be a typo.
It's hard for me to see a source for the level imbalance, especially if it always leans in the same direction. Curious.
Thanks again, as always,
Chris
It's hard for me to see a source for the level imbalance, especially if it always leans in the same direction. Curious.
Thanks again, as always,
Chris
I don't want to be a party pooper, but price difference between an Omron G5V and a nice one is $2 (at 1K up)
With a dozen relays in a case, that's $24 more, adds $150 to the retail.
Do that with everything else and the preamp will carry a $10K label.
Which is what the competition charges, that does use those prettier parts.
I don't select the relays specifically, except that they must be sealed and gold on gold contacts. I am interested in what many here think are BETTER relays than the Omron, for example. Please remember that the Parasound JC-2 is a HONDA not a Porsche.
I like Shallco silver on silver switches best, and that is what I listen through, there are no 'stinking relays' in the CTC Blowtorch, for example.
However, to be fair, and even reasonable, a good telcom relay is pretty good, in practice, IF you chose the right contacts, proper drive, etc. Usually we use 2 contacts for a single connection to 'improve' performance. Keeps Xtalk problems down too.
I like Shallco silver on silver switches best, and that is what I listen through, there are no 'stinking relays' in the CTC Blowtorch, for example.
However, to be fair, and even reasonable, a good telcom relay is pretty good, in practice, IF you chose the right contacts, proper drive, etc. Usually we use 2 contacts for a single connection to 'improve' performance. Keeps Xtalk problems down too.
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