2. amps-preamps
  3. 1042611447

If i had the money.....

I'd be ordering a set of the Parasound Halo JC-1 Monoblocks. I knew that these were going to be good, but i didn't know just HOW good. I've talked to a few people that have them and the "reviews" of these end users is just as strong as the recommendation that these amps receive in the February Stereophile.

Hard to imagine beating a product that was designed for optimum linearity / performance by an audio legend, laid out by an RF engineer in order to maintain consistent impedances throughout the entire circuit and then building the circuit with each part hand picked to "voice" the unit for optimum sonics by a "tweaker". The total approach to product building for $6K a pair !!! All of this with POWER to spare !!!

THD is predominantly all second harmonic i.e. not the typical odd order that most SS amps generate.

IMD of .0015 !!! Keep in mind that distortion typically goes up quite noticeably as power is raised and impedance lowered. This figure was taken at 4 ohms and at 600+ watts of output !!!

Output impedance of no higher than .06 ohms. This amp should keep the same "voice" and stability into just about any speaker. The power output verifies the stability and "robustness" of the circuit also....

Rated at 400 wpc @ 8 ohms

Power at clipping, broad band signal steady state:

8 ohms: 545 watts

Power at clipping, pulsed 1 KHz signal:

8 ohms: 586 watts

4 ohms: 1154 watts

2 ohms: 2255 watts

1 ohm: 4200 watts !!!

Any thougths / comments on this one ? Sean
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sean
sean OP
6,231 posts
 
Bob: Hope you had a good time at CES and everything went well.

My comments about the binding posts are based on what i've seen in pictures. They look like standard "generic" binding posts in print.

As far as my comments about the "speed" of the circuitry go, I noticed that the top octave ( 10 KHz & up ) was slightly soft and rolled. This became more apparent as impedance was dropped. According to what Atkinson measured, the amp was starting to take a nose-dive in linearity below 100 KHz. JA's testing showed a -3dB point of 95 KHz, which is pretty reasonable to say the least and much better than some amps that i've seen.

Personally, i like to see a bandwidth that is out to well beyond this point. Fast, wide-bandwidth circuitry only increases in-band linearity via improved rise time and slew rate with less in-band phase shift. Then again, one can run into problems with high frequency instability and oscillation with specific loads. Pass and Spectral gear are prime examples of "vulnerable" amps.

With that in mind, I know that John is more than capable of designing a wide-bandwidth circuit and Carl has laid out gear to well beyond the multi-MHz range. As such, my thoughts are that Parasound probably doesn't want a bunch of these amps coming back in for warranty claims. Hence this was probably a design trade-off with safety in mind.

As i've said before, nothing is perfect, but IF i had the cash.... : ) Sean
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rcrump
427 posts
 
Superior Electric posts looks "generic" as everyone copied the design and these are available in Taiwan for 1/5th the pricing of the Superiors....I used the "real" thing and this was the only thing Richard Schram, head of Parasound, made a point of with me.....No problems with the Nichicon Gold Tune or Muse electrolytics, Rel styrene/tin bypass and Zobels or Harris Hyperfast diodes in the four bridges.....It was those silly "generic" looking posts.....Oh, we could do a better amp, probably without loop feedback, with choke input supply and fet outputs, class A to full power of about 100w and few could afford it as it would run 20-25K.....
asa
662 posts
 
Well, I'm sure that these are very fine SS amps, and for the money - yes, for SS the stats do say something, and Bob Crump is upfront, skilled and not one for propaganda.

But even given that, Sean, I think you've gone off the reservation here with the circuit-tells-the-sound stuff as your point of departure.

I've never seen that view so prominent in your posts and wonder if your enthusiasm has gotten the best of you.

I'll second Tok2000. And, if you asked the Parasound's designers, then I'm confident, not coincidentally, that they would feel the same way about how to judge a component...
shubertmaniac
350 posts
 
From the literature it is Class A up to 25 watts and apparently there is an internal switch to bring it down to 10 watts if you do not want the heat. I think the JC-1s
are going to be the standard which all other solid state
amps will aspire for the price. I heard there will be a
matching preamp in the future. BTW, isn't the Blowtorch
preamp from the same set of designers?

Sean, as far as Spectral is concerned, I have NEVER had an oscillation. Neither the DMA50s nor the DMA200s have ever
had problems, oh I can blow fuses, but Spectral
stuff have tons of protection. And Sean, you can purchase
used a 200 watt DMA200 for under $2K! The thing is built like a tank and is absolutely drop dead gorgeous inside.
Personally I like it better than all Spectral amps
except the DMA360.
Idle is 800 watts, and it puts out the heat!
rcrump
427 posts
 
The bias switch is on the back and reduces the bias to the output stage....Most folks leave the amps on in low bias and then flip the switches to high bias when they are ready to do serious listening saving on the electric bill....Yes, CTC Builders designed and build the Blowtorch preamp....There will likely be a Parasound preamp......The JC-1 might as well be a CTC product as we were given complete freedom other than power output and the chassis design.....Nice project that lasted about three years including the work on the CTC BBQ (highly modified HCA-3500) we used as the mule for the JC-1....
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