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
Hi Sean, I hope you somehow get the money for these amps. Half the fun is finally getting what you want. The other half is the frustration on the long wait on getting what we want. At least you know what it is you want. You have half the battle beaten.
1 - I do not have faith in technical stats given by a manufacturer about amplifiers. It is sort of like looking at stats of a NFL playoff game... The only thing that matters is what team wins. The only thing that matters is how the amp sounds.

2 - I have little faith in any review that is published for any product. Stereophile has LOVED other products in the past that I have not liked a lot myself. They have also loved products I have loved, but now days they seem to love nearly everything they review.

3 - I would never say that I want a product until I have heard it of better yet demoed it.

4 - Power means NOTHING when judging an amps sound quality. These amps may be able to drive any speaker on the planet, but that tells me little about the way they sound. I'd take LAMM M1.1 monoblocks over about any amps I have ever heard, and they were designed in the early 90's. Not to mention that their stats are only so-so, but they are some of the best sounding amps on the planet (many publications agree by the way... ). They do put out 200wpc CLASS A power into 4 ohms! Not too many amps can match that stat. Somehow, I doubt much of the Parasound power is CLASS A.

Anyway, it is nice you are excited about an amp you have never heard but you have heard good buzz about. However, I do not beleive the buzz until I hear for myself.

Another point: To get every ounce of performance from these amps you would have to put them on two separate 30 amp circuits (yes 30 AMPS!). If one was driving a seriously innefficient speaker that had an impediance between 1 and 2 ohms (cannot think of one that is this inefficient off the top of my head...) in a big room, you could trip a 20 amp circuit with just one amp. Food for thought.....

Sean, it sounds like a dream amp for a power hungry guy like you!

Of course, it would be about 584 watts to much for my Lowthers! :^)
My audiohead buddy bought the first pair that Audio Advisor used to photograph for the cover of their latest catalog. In my humble opinion, in his system they are superb performers! By all means listen to them before you purchase!
Forget the in-home demo and take that leap of faith. Being an audiophile is not science, it's supposed to be fun. The worse thing that can happen is you make a mistake, lose alot of money and everyone on A'gon laughs at your misfortune. Like that's really going to happen.
KF- you know this, Apogee Scintilla <1ohms - the one and only.

I'm using two twenty amp dedicated circuits and a Pass Labs 600 to power them. Pass Labs assured me it would only take one 15 amp circuit, but I thought, just to be safe...
KF, gotta agree that the Lamm M1.1s are special but should point out that they put out 100 watts of pure class A magic into BOTH 8 and 4 ohms. I wish they did double down into 4 ohms!! Here is a quote from the Lamm website:

"Pure Class A hybrid amplifier producing 100 Watts continuous into 8 AND 4 Ohms, 200 Watts continuous into 2 Ohms, 300 Watts continuous into 1 Ohm."


Oops, ERATA, I mistakenly wrote the LAMMS do 200wpc CLASS A into 4 ohms. LAMM owners only wish, heh heh...

You are right Frank, The LAMMs do 100wpc pure CLASS A into 4 ohms. That is still pretty amazing since most amps cut actual Class A Power by about 75% if ohms are decreased by half. Thus if a typical amp is 100wpc Class A into 8 ohms, the amp would be effectively 25wpc class A into 4 ohms (the rest of the power would be AB).

Please correct me if my understanding is incorrect.

Check out the 250lbs Classe Omega. I think it was like something 100wpc class a, 500wpc in a/b. then like 3400wpc into some crazy low impedence. that's nuts.
Aroc: I've heard from more than a few folks, including straight from a Classe' dealers own mouth, that the Omega's are not that good sounding. Like anything else though, it is a matter of system synergy and personal preference.

I also had a response typed up to Tok2000 and Twl but it somehow disappeared from my computer. Must have happened when it locked up earlier today. Sean
I am surprised that you are spending so much time looking at specs. You know better than most, it is the sound.

I personally love Krell amps. Although the specs don't change that much as I have upgraded over the years, the sound has.

The "sound" of a unit has to do with the design of the circuit, how the circuit is laid out and the quality of the parts used. A good portion of what one hears can be described in specs IF one is provided with ALL of the pertinent specs. By "pertinent specs", i'm not talking about the typical stuff that is provided in a buyers guide either.

If the specs check out phenomenally good without having to resort to "tricks" such as high negative feedback, etc.. and one doesn't like the sound of the product, it is quite simple to alter the sonics of such a unit by changing passive parts.

What do you think that most of these "tweak guru's" do for a living ? Most of them leave the circuitry as is ( for the most part ) and simply swap higher grade components in place of what the manufacturer used. This is work that a monkey could do for the most part. It is only when one gets into altering circuit design that knowledge of circuitry comes into play.

The fact that this unit is built like a tank, has a good basic design, careful attention to parts layout and hand selected high grade parts for every inch of the circuit tells me that it should be pretty close to what you can get out of a SS circuit. Like anything else, i'm sure that it could be improved in more than a few ways. It makes life a LOT easier if you start off with something that is "solid" to begin with though.

The first thing that would have to go on these amps would be the binding posts. I'd also like it if if was a little bit faster too : ) Sean
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......
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
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.....
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...
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!
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....
Asa: I typically don't spend much time on specs because most people don't understand them or how they relate to each other. As far as "going overboard" on this specific product, i don't think that this is the case. If you look back to the last amp that i posted about after reading a review of it, it was the PS Audio HCA-2. I did make a big deal about the specs on this unit and how horrible and inconsistent they were. I also stated that i thought that specs could be interpreted to provide a reasonable idea as to how the amp might sound and react to various loads. Finding an amp that sounds good only in one system with one set of speakers with specific cables is a joke as far as i'm concerned. Looking at "real" specs can help you weed out those that lack versatility and are only suitable for specific types of loads. Sean
For those of you who've been reading my comments on other sites in recent months about the JC 1s, you may be interested that I put my money where my mouth is and bought them (from Bob). As if that wasn't enough, I decided to become a dealer and sell the JC 1s and a few other lines in my spare time.

Brian Walsh
Essential Audio
Brulee brought up a very interesting point Stereophile seem to love everything they review these days. I remember awhile back before they were bought by some huge media company, their reviews seem to be more on target, maybe its just my paronoia. Sam Tellig whom I really enjoy seem to like everything also.
OK Sean. If you get then I'd like to hear your comments.
Musicluvr i got my feb issue there is nothing to it.
I saw the absolute sound there more new products
and more interesting review.I also notice Sterophile
reviewer very few equipment they dont like,most of
the big names they like them. I am tired of reading
reviewers claiming this is the best speaker Ive heard, then
the next time, you read their column onother brand of
speaker, they will claim this is the best speaker Ive
heard. I only normally hear this words from car dealership,
Who do we trust?
Learn how to read between the lines and interpret spec's. This will give you greater insight as to what to expect out of a product. Listening to it in your system with your ears is the only way to finally judge something. Just be fair enough to work with the individual product within the confines of your system as there is no product that is a direct replacement for everything without some need for futher fine tuning. Sean

Check out the specs of most tube amps.... If they even list them........ If one was to try to interpret them, they would probably think they sound absolutely horrible compared to most solid state amps.

My theory is that the specifications of an amplifier give you a very general idea (and I do mean general idea) of how much power it has, and what kind of speaker it can drive.

Everything else should be to your ear.

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.....
I'm not going to get into the "tubes vs SS" debate on this one. I will only say that what some people think sounds "good" or "musical" is not necessarily "accurate". Nor is what some people find to be the sound of "accuracy" very "musical". There is a point somewhere in-between those two that i'm looking for and, judging by what the actual specs under test conditions show and the commentaries made by those that have listened to, reviewed and own these units, the JC-1 may fall into both categories.

I own both SS and tube amps and am looking for something that combines the best of both worlds in one simple to use package. Quite honestly, i could care less which method ( tube or SS ) such a piece ends up using, but SS is surely a LOT more convenient, reliable and cheaper in the long run. Sean
Will there be an economy model? Maybe 100 watts, 5 watts class "A", one box, internal dual mono?
Or is this the Parasound Halo A23 that Audio Advisor sells for $850???
As far as i know, the closest thing that Parasound offers to this would be the HCA-3500. The 3500 is high powered and is still very different in terms of the quality of parts used, but from what i understand, it can be modified to be quite a good sounding unit. Only problem is that by the time you're done with all of the modifications, the only thing that you have left of the original 3500 is the chassis, transformers and circuit board. The cost runs about $5K for CTC to modify these and then you still end up with an amp that isn't as good as the JC-1, which would cost less ( total ) than buying the 3500 and having it modified. On top of that, the JC-1 will still walk away from it for multiple reasons.

I can see a good sized market for a smaller stereo amp ( 10 watts Class A, 100 @ 8 / 200 @ 4 ) and Bob, John & Carl should talk to Parasound about doing something like that. If you or anyone else would be interested in such things, you should probably contact Parasound directly and ask if they have any plans to market such a product. It would let them know that there is a market for something like that if they were to get multiple inquiries. Sean
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, please describe the "voicing" process. What exactly is it and how do you go about it?
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.....

I was just stating that stats on amps are misleading. As you reinforced with your response to my previous post. Different types of distortion can mean different things to one's ears.

However, I will still maintain that stats can be very misleading while many times having little to do with how an amplifier sounds. I am sure you are familiar with the THD wars in the 80's when the theory was that the least Total Harmonic Distortion was BEST. This THD war was nonsense.

Anyway, I can look at stats all day in a magazine about amps and really have no idea on how those amps will sound in my system. Too many stats are misleading at best. For example the 'dampening factor' stat. This stat is touted by many amp designers; however, measuring dampening factor is something else entirely. The stat itself varies with the length of speaker cable you are running. Thus if you want more 'damping factor' you do the measurement with a shorter run of speaker cable.

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.....
Once again Tok20000, one has to look at ALL the specs and know what they mean / how they are arrived at to know what to make of them.

As far as your comments go about damping factor, that is the ratio that compares the output impedance of the amplifier to the load impedance of the circuit. As such, one would have to run a LOT of speaker cable to drastically alter the load impedance that the amp sees. That, or use REALLY small gauge speaker cables. Otherwise, using twice the length of cable if using a "reasonable" gauge speaker cable ( like at least 16 or 14 gauge ) wouldn't make any "real" difference in damping factor at all.

As far as your comments about low THD and the "distortion wars" of yesteryear go, i agree. The designers sacrificed a lot of other important design criteria to concentrate on achieving good specs in the area of measurable distortions. They did this using high amounts of negative feedback. Having said that, if one knew about specs, you could look at the distortion measurements AND the amount of feedback used and draw conclusions by putting 2+2 together. It is not a matter of any one spec being more important than the other, but how the various specs affect each other and work as a whole.

Mr Crump: I had no idea as to what your email was talking about until i saw this thread. I kind of wondered how you ended up talking about the CD player project when we were discussing something else : ) Sean
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.....
It would be nice if they came out with a less expensive stereo amp for the people who can not afford $6000.00 for a pair of mono-blocks. We have enough pre-amps and CDP players now. You could also look at a intergrade amp also. Money is tight now being retired I know , I would really like to be able to afford the amps you made.
Tweety, in probably less than a year these amps will probably be on the used market for between $3k and $4k. So if you can wait until a magazine declares some new greatest flavors of the month, and people get a handle on the sound of these amps (and decide if it is or is not what they are looking for), you will probably be able to pick these up for a good price used.

Sean, great composers and musicians can see the music on a page, and instantly hear it in their heads. I do not have this talent. And I sure cannot look at any specs of an amp on a written page and translate them into the sound of an amplifier, especially how it will sound in my given system. Sean, if you can do this, more power to you. I cannot. To me, this makes specifications worthless. This does not even take into consideration the fact that the specifications may be WRONG or MISLEADING. This is knowlege that you are being fed by someone else, and many times it is the manufacturer. I am not going to say that all manufacturer specs are wrong or misleading, but as with ANY information put out by a manufacturer (of Hifi magazine), the specs must be taken with a grain of salt. This is much like audio reviews. Specs can be fudged, or made to look better than they really are (through omission) or even mislead by emphasize different things.

Anyway, the only thing I fully trust is my ear. And sometimes I ask for a second opinion from a friend's ear if I have a question or need to confirm something.

On what Rcrump describes...

Yes, an integrative approach can also be applied to specs, i.e. seeing a greater whole through seeing the networking of the parts in action. Enough integration and you can develope an intuitiveness for seeing what is coming (a certain degree of prescience is what integrative knowledge gives you, which is only a further expansion of the temporal abilities that we already have; it has little to do with the parts themselves).

But, remember, Einstein said, "As far as the laws of mathematics refer to reality they are not certain, as far as they are certain they do not refer to reality."

The gear you choose is a reflection of a designer's active and receptive abilities, meaning that the sound produced, and how it may or may not catalyze your mind into deeper listening, is a finction of the designer's orientation. Attachment to the parts leads towards an analytic presentation; using the parts but transcending their attachment - seeing their future function in their integration, as Crump describes - leads to a different design and result upon the listener.

Specs is specs is specs, but you can't feel the warmth of the sun through a study of chromatics... It tells you alot ABOUT the sun (active mind), but it not the experience of the sun (receptive mind).
Hear hear!