Parasound JC-1 Questions

I have been considering these fine amps and need some advice from those who have been using them.

1.Does the amps performance suffer noticably if they are not left on 24-7? I would rather just turn them on an hour or two prior to serious listening.

2. When the amps are on (high bias) do they produce more heat than a Krell FPB mono block?

3.For those that currently own the JC-1's do you have any regrets with your choice (nothings perfect!)

All comments welcome!

1. No problem at all turning them on and off as needed. They sound better after about 45 minutes of playing music and are pretty much fully warmed up after 90 minutes.

2. I don't know. What is the heat dissipation of a Krell? It may be possible to estimate that of a JC-1 as follows. Continuous power output into 4 ohms is 800 watts RMS, while the input power while driving that load at full power is 1280 watts. Thus it would follow the 480 watts difference is dissipated as heat, or about 1640 BTU/hr. Of course in actual use it wouldn't be driving a purely resistive load, nor would it be operating at full power output continuously. So the real power dissipation would be a fraction of that.

3. No, but then I bought them as a consumer before becoming a dealer for them.

#1,no need to leave on all the time.just let them warm up a bit.#2dont know about comparison,but the jc-1 do run very warm in class a.#3these currently sell 4000.00 or less here,i dont how you can do better for s.s.had c-j prem.140 prior,and to me i lost nothing and gained bass clarity.both are excellent.
1. No need to leave them on all the time. In my system they sound their best after they have been on for at least 90 minutes, and even better as the day goes on.
2. Don't know about the Krells. The JC-1's get pretty warm on LOW BIAS, and pretty hot on HIGH BIAS, but not excessively so in my personal opinion.
3. No regrets at all! These amps have the deepest, tightest, and most powerful bass I have ever heard in my system, as well as exceptional speed, transparency, focus, and detail resolution. They have great image width and depth, and very clearly resolve fine and subtle nuances in the music, as well as reverb trails, etc. They are also notably free from etch, grain, and glare. They also have excellent top-end extension and a very palpable midrange.
All this, and my system is no where near state-of-the-art, nor even that expensive in audiophile terms!
But, they must be FULLY BROKEN-IN to sound their best! This takes about 60 days of 24/7 music signal being played through them. I used an AM/FM tuner, with the volume on my preamp turned just above a whisper for 60 days, 24/7 to break mine in. Simply leaving them on all the time with no music signal for 60 days, 24/7, WILL NOT BREAK THEM IN! They must have a signal to properly and fully break them in.
They sound decent out of the box and up until they fully break-in, but once they do break-in, WOW! They suddenly transform, they are in a different league! They are truly amazing once they hit that stride. Up until they do break-in, they are very unpredictable...a few days they will sound closed-in, rolled-off, dark, excessively warm, and boomy in the bass...then other days they will sound thin, forward, and bright. They also have virtually no image depth at first, but they have it in SPADES after break-in.
Once break-in occurs, they are become exceptionally neutral, and their outstanding sonic characteristics and strengths do not change.
These were MY personal experiences with my JC-1's, in MY personal stereo system. Others experiences with them may vary.
Hope this helps.
I have to say that I am the only one does not think that they get that hot. I have them on a rack iwth the recomended 6 inches of clearence abouve them, and they really are really just warm to the touch (now you have to tkae into consideration that before I got them everyone said they would be extremely perhaps by expectations simply exceded reality). The answer is while they are running in hi bias mode I can easily put my hands on top of them without burning myself. I hope that helps.

Thanks for the response's, very helpfull and interesting.

I have read some old posts regarding the long break in period, 60 days of 24-7 is a long time to achieve consistant performance, but sounds like most agree the wait is worth it.

I am glad to hear the amps perform well after a hour or so of warm up, that makes the heat factor less of a concern for me.
There is the answer to why there is a divergence of opinion on how hot the amps run. Parasound told me that within the parameter of the design, there is a range of bias that is acceptable, I believe within 10 degrees F. One of mine ran 9 degrees hotter, and, believe me, I could feel the difference. I had the bias lowered to be close to the other one. When it was biased hotter, you could not leave your hand on it for more than 8 seconds without feeling uncomfortable. Only 9 degrees made this much diffference. To the touch, I thought the difference was greater than 9 degrees, but I used a digital thermometer and made extensive, careful measurements, so I am sure of the temperatures.

The odd thing is that I like the way they sound in low bias nearly as much, as I use them primarily in low bias, and then don't have to worry about the heat or the electric bill!
my experience is also that with adequate space for ventilation they are warm to the touch at most,even after days of being left on in high biased mode.once e-mailed
Bob Crump to ask him about this and he answered that he couldn't understand why people were saying they ran so hot.
Kevziek, when you had the bias lowered on the one of your amps, did you have to send it back to Parasound, or did you or your dealer make the adjustment?

I will probably check the bias after the 2 months of break in.
1)By now, it sounds as if you understand that they only need to be powered on w/signal 24/7x60
for break-in, after that it's business as usual.
90-120 minute warmup and your good to go.

2) Don't know about the Krell, but, my JC-1's have no restrictions around them (see system pics).
In low bias, even after cranking awhile, I can hold my hands on the heat sinks indefinitely.
In high bias mode, after cranking awhile, I really wouldn't want to hold my hands on the heat sinks for more than a few seconds.
But, this is to be expected in high bias mode. It's not like their sizzling hot and you'd burn yourself just touching them for a few seconds. Let's just say it's uncomfortable.

3) No regrets-they rock!
Darn, Perfectionist! My amps didn't come with lava lamps!

Nice pics!

Thanks Brian, they're the Starship MKII Special Edition
with TG Audio SLVR PC's and they match my JC-1's to a T :)

What I want to see is pics of YOUR system :(
Yours for the asking! :-) Go to the Products page on my website (my username(dot)com ) and click the "Click here" link near the top of the page for a view of the amps and speakers...I'll get around to the front end photos one of these days.

Amazing Brian, a good dealer would have given you dual mono lava lamps with the purchase or at least green stamps! Bet all you received was some aftermarket power cords as well as a checkout of your amps.......
I didn't get the Mothra power plant and tailings ponds with them, either, Bob. Of course any good dealer (can you name one?) would provide red and blue lava lamps and configure them for the left and right channels so you would know whether you are coming or going, as starboard and port...they need to be swapped for recordings that are out of phase... I don't have access to the Starship models so I make do with small bottles of Aceite de Culebra which have developed a cult following among the cognoscenti and have been a big hit at pizza and beer parties...
It is amazing that the world supply of Aceite de Culebra hasn't been depleted by the cognosenti as it is mined very close to the vacuum mines that used to provide six nines oxygen free vacuum before the collapse. I have often wondered what tube makers have been using since the mine collapsed and that is another story, but I do know it.......I have almost a pint of Aceite de Culebra which should last me 20-30 years of normal use.......