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Parasound JC2 Preamplifier Review

amirm

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#1
This is a review and detailed measurements of the Parasound JC2 Preamp. It was kindly sent to me by a member. The JC2 is replaced with JC2 BP. It cost US $4,000 when it first came out (2009).

This is one heavy preamplifier which weighs as much as some power amps!

Parasound JC2 Preamplifier Balanced Audio Review.jpg


The design is elegant and differentiated. There is independent gain controls for each input which can let you set channel balance. The knobs are very small and slippery though making this a bit hard.

The back panel shows where some of the cost has gone as these are probably the best connectors I have seen on an amplifier:

Parasound JC2 Preamplifier Balanced Back Panel XLR Audio Review.jpg


As I have magnified, the claim to fame of this preamp is the designer behind it: John Curl. If I were to name top 10 famous designers of audio electronics, he would have a solid spot there (as far as fame). He is quite active in forums as well. So it is very nice to get one of his designs on the bench and see how it performs.

Preamplifier Audio Measurements
As usual, we feed a 1 kHz from the ultra low noise and distortion generator in my Audio Precision APx555 analyzer and see what else comes out beside it:

Parasound JC2 Preamplifier Balanced Audio Measurements.png


Oh. This is not nice. We have a third harmonic peaking way up there near 90 dB. This in turn sets our SINAD which is a sum of distortion and noise to the same value. With CD's noise floor being -96 dB, we have distortion products which would peak above that.

Sweeping the level we get this:

EDIT: the title of this graph is wrong. The load was 200,000 ohm, not 300.

Parasound JC2 Preamplifier Balanced THD+N vs Level Audio Measurements.png


As we see, it is not competitive with a $400, albeit state of the art, headphone amplifier. Its sweet spot is around 1.2 volt out which is anemic for balanced output.

Fortunately the company is honest with both distortion spec (above) and noise (below):
Parasound JC2 Preamplifier Balanced SNR Audio Measurements.png


Multitone test shows rising intermodulation distortion as frequencies go up:

Parasound JC2 Preamplifier Balanced Multitone Audio Measurements.png


We see this dramatically in wideband test of THD+N versus frequency:

Parasound JC2 Preamplifier Balanced THD+N vs frequency Audio Measurements.png


Notice how the gain controls have their own distortion characteristics, performing worse when lower gain than higher(!). This is some odd behavior.

Using dual tones and measuring intermodulation distortion this time versus level we get:

Parasound JC2 Preamplifier Balanced IMD vs Level Audio Measurements.png


So way worse than state-of-the-art preamplifiers like the Benchmark HPA4.

Crosstalk and frequency response are fine:

Parasound JC2 Preamplifier Balanced Crosstalk Audio Measurements.png


Parasound JC2 Preamplifier Balanced Frequency Response Audio Measurements.png


Channel matching was not great though:

Parasound JC2 Preamplifier Balanced Channel matching Audio Measurements.png


As you see, performance drops not at the end of the scale but somewhere in before that. You get nearly 1.25 dB when listening quietly which will cause a soundstage shift.

Finally here is a dual tone 19+20 kHz intermodulation test:

Parasound JC2 Preamplifier Balanced 19+20 kHz intermodulation Audio Measurements.png


Not a good showing.

Conclusions
This preamplifier was measured by stereophile which stated it had exceptional performance. I am not seeing any signs of that, nor where there enough documentation in said measurements for me to try to fully replicate them. As it is, performance is good enough for most people to not hear the impairments. But poor enough to bother the heck out of me that $4,000 was paid but you got average results. You can get far better performance from Schiit Freya S for just $600. Or you could go to Benchmark HPA4 for $3000. Neither had the nice look and feel of the JC2 but deliver where it counts: transparency.

Needless to say, I cannot recommend the Parasound JC2.

------------
As always, questions, comments, recommendations, etc. are welcome.

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Wes

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#2
The others mentioned are more modern - has pre-amp design changed much in 10 years?

I suspect not...
 

Dialectic

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#3
And to think that the mags held out these Parasound Halo products as examples of superb "traditional" engineering in high-end audio electronics.

Thanks to Amir for measuring.
 

Xulonn

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#5
OMG! Knock me over with a feather...a Schiit preamplifier recommended over a Parasound John Curl unit?

Falling Over.gif
 

Vasr

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#7
Wasn't John Curl (like Nelson Pass, etc) known to design for a "sound signature" rather than transparency?
 
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#8
wait, it just pre-amps and has a score this much low?!
 

Sorabji

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#9
John Curl is very knowledgeable about circuit design. He's also a true believer in many high end audio myths, such as low feedback, which is apparent in this unit. And here's an exact quote from an online forum: "ABX testing doesn't work". What more is there to say?
 

suttondesign

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#12
When I recently built some Linkwitz LXmini's and a couple of small, home-brew subs to sit behind them, I decided to go with bargain-basement DSP (MiniDSP 2x4HD and a MiniDSP ICEpower subwoofer plate amp) and amplification (an old Adcom 4-channel amp bought on Craigslist) until some lucky event allows me to get into SOTA amplification and DSP. I did that because this site, over the past 2 years, has demonstrated that the well-known manufacturers of old have abandoned pursuit of SOTA in favor of hocus-pocus, puffery, and fancy cases and knobs. Why waste money on middling gear if the cheap stuff is about as good?

On the analog side, this site (thanks yet again to Amir, wow) has allowed us all to see how Benchmark Media, Hypex, and Purifi have changed the game in audio. At this point, I won't consider amplification from anyone else as a step-up from the bargain stuff I'm using because I see no point in buying anything that's not generously over 16-bit resolution.

Parasound has put out some really mediocre equipment, adding features or faceplates or whatever but not advancing anything. And they're certainly not alone in resting on their laurels. I reserve judgment for ATI, which is introducing potent, promising class-D amps (but with toroidal transformers, for reasons I don't quite get) alongside ostensible upgrades to their traditional designs. I want to see how those new ATI designs measure, for sure, because they seem to offer good value in the multi-channel configurations (about $375 per channel of amplification, which is pretty good). But when March Audio and others can put out enormously-powerful class-D amps which run small and cool, and at prices no higher than monsters with low S/N, why would I consider anything else? I run all-digital front ends with sophisticated gear capable of high resolution audio (or at least CD redbook, which is good enough for my ears), and all I'm asking is that the analog side give me a clean 16 bits too. Alas, the old-line manufacturers don't care.

It is just so interesting that we still don't have significant market entry into the high-resolution-amplification sector here in the US. It's Benchmark and then a few marketers of cases with Hypex, Purifi, ICEpower, and Pascal modules. It's as if the traditional manufacturers of hi-fi in this country just don't care anymore. All they want to do is go to audio shows and give us bling and hype that subjective reviewers then spew out in their nonsense reviews.

Thank you, Benchmark, Hypex, Purifi, and other innovators!
 

Vini darko

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#13
Is my understanding flawed, thought thrid harmonic is the one you don't want? Second is supposedly the nice one?
(for that money I'd rather there weren't any above - 100db)
 

Nathan_A

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#16
I'm kind of surprised and not surprised by this. My Parasound P5's preamplifier functionality seemed to measure very well according to the Stereophile measurements. I assume it was all the audiophiling of this JC2 that made it worse relative to the "budget" P5.
 

Silly Valley

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#17
It would be very interesting to see how the current much less expensive Parasound Halo P6 (or even P5) with their smps power supplies measure up. Also, the New Classic 200 Pre as well. Priced at $1500, $1100 and $895, and with many more features, how much do you sacrifice if any?
 

Nathan_A

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#18
It would be very interesting to see how the current much less expensive Parasound Halo P6 (or even P5) with their smps power supplies measure up. Also, the New Classic 200 Pre as well. Priced at $1500, $1100 and $895, and with many more features, how much do you sacrifice if any?
When I drop off my Yamaha MX-1 with @amirm, I'm happy to bring along my Parasound P5 with it. Currently, pulled both out of my system to try out a Soncoz SGD1 fed straight into an Icepower 1200AS2 based amp.

The P5 is an odd bird in their line-up. It's very "not audiophile" if you take a look inside.
 

Feanor

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#19
Is my understanding flawed, thought thrid harmonic is the one you don't want? Second is supposedly the nice one?
(for that money I'd rather there weren't any above - 100db)
4th and higher -- especially higher -- is considered bad. 2nd and 3rd tolerable. (It's been know since antiquity the higher order harmonics sound harsh and discordant).

Amir's testing demonstrates a high amount of 3rd order distortion especially, something also apparent in Pass designs. Make no mistake: this is what they are striving for.

By the way, I just ordered a Schiit Freya +: everything the Freya S has got plus a tube option.
 

Lbstyling

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#20
Just for fun, I have deliberately not read the review... Yet

I owned one of these.

My subjective experience was it had no/little low level detail retrieval, and sounded overly 'warm' (lacking top end). When you turned the wick up, it got warmer and more bassy/less treble......
 
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