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

Showing 8 responses by rcrump

rcrump
427 posts
 
Tok2000, it isn't the amount of distortion as much as the nature of the distortion as tubes have 2nd and 3rd harmonics and not much else, certainly no higher order odd harmonics....Spectral analysis equates to what we hear fairly well.....You want to talk distortion look at the recording process as looking at 5-20% on most recordings.....
rcrump
427 posts
 
Sean, the first thing to go would be the binding posts? I chose the Superior Electric as they are the best sounding as well as the most rugged of all the ones available.....I have run four of the JC-1s on one twenty amp circuit and have had no problems whatsoever......Atkinson had way too much fun with the specs and think Parasound's specs of .2% distortion for clipping is a better place to be than Stereophile's 1%....Yes the amps are powerful as they drove the heck out of the Sound Lab speakers at the CES, a feat in itself.....Glad the review is finally out as have been biting my tongue now for a couple months....The amp is the best we can do in a machine made very powerful amplifier......The amp would run three times the price if made here in the USA by hand....This is probably the first high end product to be machine made overseas with no scrimping on parts quality......
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.....
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....
rcrump
427 posts
 
Our next project for Parasound will likely be CDP with some preamp functions.....The JC-1 was an experiment for Parasound and it appears to have worked well.....They have had all the amps engineered by Curl and they are all pretty much the same with the differences being layout and parts quality......It is Parasound's choice if they want Carl Thompson and I to work on their other products......
rcrump
427 posts
 
Voicing is easy, just parts choices based upon twenty-five years of playing with various parts....I keep a journal of what various parts do in various parts of a circuit as most resistors measure pretty much the same and they all sound different in use as do caps, wires, switches and connectors....You do it long enough and you can look at a piece and tell what it will sound like just looking at the parts used.....I come from the school of get your hands dirty, take notes and before long it will start making sense.....Voicing the Parasound amp took about a year and a half of work on the HCA-3500 I used as a prototype and then a few months with the JC-1 prototypes before the units went into production....The bulk of the time was in break-in as I rebuilt the HCA-3500 in several stages......I voice for complete break-in and complete warm-up, 60 days and 5 days.....
rcrump
427 posts
 
Tok2000, I certainly agree as, other than S/N, spectral analysis and shipping weight (for when it breaks) most of the specs don't mean much.....I don't deal with these, but my partner sure does going on about higher order odd harmonics big time.....I just deal in sound and hopefully some folks will like the way the JC-1 sounds....I do and guess that is what really matters in the long run as I am happy with the results.....
rcrump
427 posts
 
Cdc asked about a smaller amp and I told him what we had in mind as our next project....Parasound wanted a preamp, but think I have them convinced that the world didn't need another 3-4K preamp, but needed a really good CDP with some preamp functions.....
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