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!
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:
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:
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.
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):
Multitone test shows rising intermodulation distortion as frequencies go up:
We see this dramatically in wideband test of THD+N versus frequency:
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:
So way worse than state-of-the-art preamplifiers like the Benchmark HPA4.
Crosstalk and frequency response are fine:
Channel matching was not great though:
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:
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.
Nothing has changed since yesterday. Or the day before. I needed money then, and I need it today. So please donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
This is one heavy preamplifier which weighs as much as some power amps!
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:
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:
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.
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):
Multitone test shows rising intermodulation distortion as frequencies go up:
We see this dramatically in wideband test of THD+N versus frequency:
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:
So way worse than state-of-the-art preamplifiers like the Benchmark HPA4.
Crosstalk and frequency response are fine:
Channel matching was not great though:
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:
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.
Nothing has changed since yesterday. Or the day before. I needed money then, and I need it today. So please donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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