Switch A51 to JC-1's

[Jeff Mayer]

Interested to know if anyone here has uses JC-1's in a 13' by15' room. I've got 92db speakers. Considering selling my 1 1/2 year old A51 since I moved and don't have the room for surrounds so haven't been using 3 channels for six months now. I do 80% music/20 movies anyway. Anybody know where I can get the best price (shipped to Philadelphia) on a pair of JC-1's. Thanks a bunch,

Jeff

[Peter Nielsen]

Jeff,

With 92dB/W speakers (=efficient ones!), you could probably get by with an A21. Replacing your A51 with an A21 will be a noticeable upgrade.

Remember that the JC1s emit a lot of heat, which places constraints on how you place them and may be a problem in hot summer months depending on where you live and if you have good air conditioning. I moved on to digital amps because of heat issues and high electric bills :B

If you want to try something different... :

TacT S2150
PS Audio GCA

Peter

[Chris D]

I agree, JC-1's not necessary, but hey, if you can do it, go for it!

Are you looking to buy new, or used? (new, talk to Brent Huskins at Media Design's banner ad at the top of the page)

[locomk]

Jeff,

With 92dB/W speakers (=efficient ones!), you could probably get by with an A21. Replacing your A51 with an A21 will be a noticeable upgrade.


Peter

wouldn't the currant difference on the jc1 be better than the a21. plus 10-25 watts of class a versus the a21's 5-6. i use a A21 halo now for my front speakers 90db/w, but am curious on how the jc1 will sound with my speakers.

[Chris D]

Sure, the JC-1 is going to be a big step up from the A21, much less the A51 or A23. It's an amp in a totally different class. Are you asking for the difference to be quantified?

If so, you'd have to stick with the specs.

[Peter Nielsen]

wouldn't the currant difference on the jc1 be better than the a21. plus 10-25 watts of class a versus the a21's 5-6. i use a A21 halo now for my front speakers 90db/w, but am curious on how the jc1 will sound with my speakers.

Well, without doubt the JC1 will sound better, especially if you need the power.

If your speaker allows, an even better route is to go with active bi-amping. (I am now using active bi-amping for all my speakers).

Peter

[locomk]

currently i cant play music too loud, i want clarity not volume. the a21 was such a big jump from using my yami. bi-amping is nice but dont have the money to do so right now, one day...

[Peter Nielsen]

currently i cant play music too loud, i want clarity not volume. the a21 was such a big jump from using my yami. bi-amping is nice but dont have the money to do so right now, one day...

The JC1 will not be a "big" jump from the A21, unless you have power hungry speakers that actually will use the power...

I'd suggest spending the money on acoustic treatments and/or speaker upgrades. That will make a much bigger difference...

Peter

[Jeff Mayer]

Peter-

I'm not too concerned with the heat or electric bills since I run the amps only when necessary. I remember you were running 9 jc-1's...did you leave them on most of the time? When things heat up in the summer I can run one or two small quiet fans on them.
In your mind, how does digital amplification compare to the JC-1's strictly in terms of sound quality?
I'm looking at either new or used. Worried about the warranty if I buy used... but like the money I could save.
Jeff

[mikepinkerton]

Why is the A21 such a big jump from the A51? I figured they were very close, just 2 vs. 5 channels. Am I missing something obvious?

-Mike

[Chris D]

Yes, they do have very similar ratings, and have the same wpc as each other. If you just look at the back panel of the two, and open them up, you'll see that the A21 is a unit more dedicated to sonic quality for each of the two channels. (that's why in a 7 channel 1-series system, I recommend people use the A21 for the front mains, not the rear surrounds) This issue has come up before--I think Peter actually has some more techie info on the difference.

[nbourbaki]

The A51 has a total of 164,000 uF power supply filter capacitance which works out to about 32,800uF per channel. The A21 has a total of 100,000 uF power supply filter capacitance which because it's only a two channel amp works out to 50,000uF per channel. The higher the capacitance the more energy is available for dynamic power.

The A21 has a 1.2 kVA power transformer which is shared by two channels. The A51 has a 2.2 kVA power transformer which is shared by 5 channels, so the A21 has a more robust power supply.

Of course the JC-1 smokes both the A21 and A51 with 132,000 µF Nichicon Gold Tune capacitance per channel (since the JC-1 is a mono block) and a 1.9 kVA power transformer.

But with 92dB/W efficient speakers I can't believe that the A21 will be a noticable improvment over the A51.

[Vince Helm]

But with 92dB/W efficient speakers I can't believe that the A21 will be a noticable improvment over the A51.

Don't underestimate the power of the force.

[Peter Nielsen]

I'm not too concerned with the heat or electric bills since I run the amps only when necessary. I remember you were running 9 jc-1's...did you leave them on most of the time? When things heat up in the summer I can run one or two small quiet fans on them.

The amps themself can take the heat. The problem was that when the room reached 85F after four hours of listening, I was no longer comfortable... (It was very nice in the winter time though :B )

If you have the amps free-standing, they will not require a fan.

I never left the JC-1s on all the time. If you do that, a pair of JC-1s will consume power for ~$450/year.

In your mind, how does digital amplification compare to the JC-1's strictly in terms of sound quality?

This depends on the digital amp. I don't have any experience with the B&O ASP based amps, but the TacT amps sound just as good as the JC-1s.

I'm looking at either new or used. Worried about the warranty if I buy used... but like the money I could save.

The Parasound A21 and JC1s are very solid amps. IMHO, they can safely be bought used. When it comes to digital amps, I'd stay away from used ones...

Peter

[Peter Nielsen]

But with 92dB/W efficient speakers I can't believe that the A21 will be a noticable improvment over the A51.

Well... There is a noticable difference between the A51 and A21. When I pushed the A51 it blew the midrange fuse in one of my speakers :E and the clipping sound is dreadful. The A21 behaved much better, and audibly provided a much nicer "clipping" sound when it reached its limit. No blowing fuses with the A21. It's clear that it has a much more robust power supply. I would go with the A21 for my fronts and save the A51 for lighter duties...

Peter

[nbourbaki]

Well... There is a noticable difference between the A51 and A21. When I pushed the A51 it blew the midrange fuse in one of my speakers :E and the clipping sound is dreadful. The A21 behaved much better, and audibly provided a much nicer "clipping" sound when it reached its limit. No blowing fuses with the A21. It's clear that it has a much more robust power supply. I would go with the A21 for my fronts and save the A51 for lighter duties...

Peter

Peter, I was referring to the differences between the amps with a pair of 92db/W efficient speakers. Those Maggies you're running are only 85db/w @ 4Ohms, big difference. My Paradigm 60's are only 91 dB/W and even running the speakers full range I haven't come close to clipping.

[Peter Nielsen]

Peter, I was referring to the differences between the amps with a pair of 92db/W efficient speakers. Those Maggies you're running are only 85db/w @ 4Ohms, big difference. My Paradigm 60's are only 91 dB/W and even running the speakers full range I haven't come close to clipping.

Sure, but when you push the amp to the limit even the 92dB/W speakers will show similar results. The A51 may burn out the speaker/fuse while the A21 doesn't...

With my Maggies I was able to push the amp to its limit without playing too loud in a fairly small room (15x22') because the Maggies are inefficient.

If you play really loud (concert levels), you may also hit the amp limit with 92dB speakers. Or, if you put the speakers outdoors or in a really large room, you may also hit the limit even when not playing too loud...

Oh, but you're right when it comes to the 4 ohm speaker rating. With 8 ohm speakers, the A51 probably will behave better and more similar to the A21! 4 ohm speakers need more current, and are inherently more demanding on the amplifier, especially on the power supply where the A21 excels.

Peter

[REOFan]

Go With JC 1s

If you can get a deal for the JC 1s that satifies you, get the JC 1s. They sound great, look great, and function flawlessly. I've had mine since their introduction and have never looked back. My room is about the same size as yours. The room is in the basement of my home in Wisconsin (about 35 degrees today; but our November has been unseasonably warm up until now--so no complaints here), and it doesn't get uncomfortable when running the amps full tilt. Cheers.

[Peter Nielsen]

about 35 degrees today

The temp OUTSIDE seldom gets this cold here...

Don't follow this piece of advice blindly if you live in a southern state (NC is too warm for the JC1 in the summer time).

Currently 80F with digital amps (or the same with amps off).

I've experienced a room temperature of 94F with JC1s. Not comfortable!

Peter

[REOFan]

JC 1s Are Cool

Peter,

Summers in Wisconsin can easily reach 80 to 90 degrees. My comment about the temperature was about our weather in November (we got ten inches of snow today--December 1--and my darn snowblower stopped working midway through my snow-clearing job). Two Jc 1s are, in my humble opinon, a terrifice buy (choice). I cannot speak to having more than two JC 1s; I have but two. But I think two would work well, say, in Arizona or New Mexico or any state for that matter. I also cannot speak to the late fall temps in North Carolina (being born and raised in Wisconsin). So I don't think my advice had anything to do about "blindness." My amps have never made my room "uncomfortable." More than two, however, might (thought I'd likely save on heating expenses in the winter).

I was admitteedly surprised to see you sell your JC 1s. But, I certainly respect your decision. Did you sell them all? I am confident you are satisfied with your current amps. I've enjoyed your posts on this forum, and I'm glad you continue to contribute. But I believe the JC 1s are terrific amps. Peace, my friend.

[Peter Nielsen]

I was admitteedly surprised to see you sell your JC 1s. But, I certainly respect your decision. Did you sell them all? I am confident you are satisfied with your current amps. I've enjoyed your posts on this forum, and I'm glad you continue to contribute. But I believe the JC 1s are terrific amps. Peace, my friend.

I agree. The JC1s sound great and have enormous power. However, they do require good air conditioning.

What good will a great amp do if the air conditioner is running all the time and making a lot of noise.

Ideally, I would have kept all the JC1s and designed a special room for them. However, I came to the conclusion that this would not be worth the cost (especially considering that I do not know how long I will stay in my current home).

I sold all my JC1s. BTW, the 2nd hand value of these amps is *extremely good*. This actually makes buying a pair of JC1 easier. If you don't like them, they can easily be sold without a huge loss.

Peter