Why all these JC-1's for sale?

Probably several factors involved here.

1) Things are tight and it is tax time.

2) People that can afford to buy $6K amps often do so i.e. "flavour of the month" club. CES just took place and they saw something else that has their mouth watering.

3) Their preferences and / or system goals have changed. Many folks are moving from big systems to smaller systems. In the process of this change, they are swinging from SS behemoths to tiny tubes.

4) These amps don't have enough sonic colourations to keep them happy / band-aid the rest of their system.

5) The amps aren't performing up to snuff due to a lack of available current i.e. each should have their own 20 amp AC line. As such, they blame the amp when there are other problems.

6) The heat and power consumption of these amps are more than they bargained for.

7) They don't have enough space for these amps. Two amps instead of one, both generating heat and requiring more space to dissipate that heat, etc....

8) After purchasing these amps and dealing with trying to locate them in their existing rack using their existing cables, they now realize that they have to buy more cabling, probably of various lengths. They don't want to go through finding suitable cabling, pay the price for such or re-configure their entire system

9) The rest of their system is below the sonic potentials of these amps. They therefore blame the amps for what they hear.

Need i say more ???? Sean
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Chams: The review samples that BFS used were defective units i.e. had incorrect part values used in a section of the circuitry. Marty continues to refer to his experiences with the JC-1's even though he knows that the units were defective and not representative of current production standards. Given that Parasound admits that they had production problems with the earliest units and corrected this flaw, this is neither fare to the JC-1's or "ethical" for Marty to do so in my opinion. Kind of like saying that a turtle is faster than a rabbit even though you know that the rabbit that you're basing your comments on is wounded. Sean
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PS... I have never heard these amps but have a great amount of respect for the people that were involved in making them happen. There are a few design revisions that i'd like to see made to them, but who am i to suggest such things??? : )

Audioengr:

If you can run these amps off of a single 20 amp line and aren't encountering any problems with them, you're obviously not driving them very hard. That could be due to having very efficient speakers, high impedance spekars, a small listening room, low average listening levels, etc...

In order to put out power, it takes power to operate. This is NOT a "high efficiency" switching amp and it is biased quite high, so low current draw is not a strong point of these amps. They are "thirsty" amps due to their higher bias levels. By their very design, "thirsty" amps will generate a lot of heat. My "high bias" amps idle at about 130* F at the heatsink with the air conditioning on. If i left them on without the air in the middle of the summer, they would be up around 140* - 150* or so.

On top of all of that, if your "bias adjustments" are lowering the temperature of the amplifier at idle, you've simply reduced the amount of power available from the amp while remaining in Class A mode. This assumes that there isn't multiple bias adjustments for the output stage and that there is a mismatch between those adjustments. This would also account for your lower current draw from the wall as reducing the bias levels reduces current draw and increases amplifier efficiency, but it does so at the expense of linearity and sonics. In effect, it sounds as if you're defeating the design principles of the amp. Sean
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Audioengr: You didn't address any of the points that i brought up. On top of that, if you're not pulling anything above the steady state draw that the amp produces at idle, you're listening to elevator music and / or have very high efficiency and / or high impedance speakers. Other than that, the only way that you can lower heat dissipation is to lower the bias of the unit OR to replace all of the output devices with matched units that have been run on a curve tracer. Given that the latter is not real probable, the former is the only possible answer that i'm aware of. Sean
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I think that many people confuse "leaving the amps turned on but with little to no signal passing through them" with actual "break-in" time. While the idle current consumed and heat generated will help somewhat, there's nothing like throttling the amp to move things along. This has to do with the dynamic stress that components undergo when amplifying a signal, varying amplitude output levels and switching specific circuitry off & on, etc...

On top of that, and while i'm a big proponent of leaving high bias amps turned on, i do recommend turning these off after being on for a few days and letting them heat-down. This increases the thermal swing that the components under-go not to mention the increased "stress" caused by the massive in-rush current drawn when firing them back up.

As a side note, if a component is going to fail, it is most likely that it will fail when firing it up from being stone cold. This is due to the aforementioned problems with in-rush current and rapid thermal changes. As such, turning the amps off every now and then, letting them discharge fully overnight and then firing them back up in the morning is a good way to find out if you've got a unit with a potential problem.

If you're going to do this, do it early in the week so that when you turn it back on, the amp will be back up to a stabiized temperature for week-end listening sessions. As i've stated before, high bias amps sound best to me after being powered up for an uninterupted 48 - 72 hours or so. Just make sure that they have more than adequate ventilation. Sean
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Audioengr: I don't doubt that the amps weren't a "matched pair" and / or operating exactly as they should. This is part of the problem with buying mass produced gear. Having said that, we've already seen that many "custom built" and "mega-dollar" components come out of factory with BIG problems and a lack of quality control. This is why i align all of the products that i sell before i sell them. I also tell the customer to bring the units back in after a couple of months of normal use. That way, i can inspect and adjust as needed.

If someone wants to obtain optimum performance from their gear, they really should have it spec'd and possibly aligned AFTER running it in for a period of time. Components do change, circuits do settle and adjustments shift. Anybody that tells you that they don't is either lying to you, knows not of what they speak or are dealing with circuitry that is so over-designed and lacking in thermal stress that only the government could afford it.

With that in mind, idle current of the amp is spec'd at 250 watts. While i would have to assume that this is in high bias mode, 250 watts of steady state dissipation will surely dissipate a sizable amount of heat. That's appr as much as two backyard flood lamps, which would surely scorch your skin after being turned on for a period of time. These amps are also spec'd at pulling well over a kilowatt each when driven hard, which will surely heat things up a bit too. On top of that, 1000+ watts of demand per amp ( when throttling the system ) will surely cause voltage sag in most 20 amp circuits, hence my other comments pertaining to your AC set-up. That's why i said that you must either have very high efficiency speakers, high impedance speakers and / or not listen very loudly at all. Even so, if left on in high bias mode, your amps should be getting noticeably warm. If they don't, they aren't running in Class A. Sean
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