Parasound JC1's vs. Sim Audio W10

I agree with Audioengr's comments about global feedback vs no global feedback. That is, the amps with global feedback will typically produce more "slam" and tighter bass than the designs that lack global feedback. Part of this has to do with the amps having global feedback having a lower effective output impedance. The drawback to this is that most amps with global feedback will lose midrange liquidity and tend to sound "closed in", "less spacious" and lack separation of notes in terms of midrange and high frequency response. The more global feedback that is used, the more noticeable this becomes.

This is why i've said that Pass amps ( new and old ) sound very nice but lack bass definition and oomph. Even though the newer X series have massive power supplies and great current capacity in the output stage, their circuit design i.e. non-global feedback and slightly higher output impedance is what limits their bass performance.

Too bad we can't get someone like Curl and Pass to work together on designing an amp and then have someone build it with good quality parts. I think that both of these guys are capable of stunning work and the end result would be a pretty fabulous product.

Sim Audio? Never heard any of it. Read some very nice things about their products, but nothing earth-shattering.

MBL 101's??? Good luck. Finding amps that are both good enough sounding and powerful enough to really throttle them as needed may be a life-long task. I wish you all the best and hope you enjoy the journey : ) Sean
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Downunder: I would not have expected the Pass amp to be a good match with your speakers. Most Pass amps are a little "round" sounding in the bass, albeit in a pleasant manner. The problem is that, when you combine it with speakers that lack damping, suffer from ringing and are round sounding to begin with, you've got WAY too much of a good thing. The Vienna's definitely fall into that category, at least in my opinion.

As to the high feedback amps sounding "closed in", this is what i predicted that the JC-1 would sound like after learning that it used gobs of negative feedback. While i was initially eager to hear this amp, after finding out more about the technical aspects of the design, i knew that i would not like it sonically. Somewhere in the archives, you'll find those comments, along with what i posted above. That is, high negative feedback designs tend to sound less liquid and sterile. They measure good on the bench, but simply don't sound "magical" or "musical".

As such, i don't doubt your results at all. In fact, a couple of them simply confirm previous observations that i've already made, all without hearing the gear or combo of gear in question.

There is one thing i'd like to add though. That is, you guys really need to check into using low impedance speaker cabling ( 20 ohms at MAX ) with amps of this calibre. The benefits with amps of "marginal" build quality are noticeable, but when you've got a real "powerhouse" of an amp using good quality parts, the benefits become even more apparent. That last level of "musical accuracy" i.e. "detailed notes that float in the air, dripping liquidity and impact" become a reality. That's because the amp can finally "load up" into the speakers and the power transfer characteristics are improved. Better power transfer characteristics means increased control, reduced reflections and improved sonics.

In my Dad's system, i changed his preamp, power amp, DAC, modified his speakers, changed interconnects, etc... When i finally installed some low impedance speaker cabling, he told me that those speaker cables made more of a difference than all of the other changes combined. What he didn't seem to take into account was that the change in speaker cables simply allowed him to hear all the benefits of the upgrades that had already taken place, which his other speaker cables simply didn't let through. After all, the cables aren't doing anything magic, they are simply reducing losses in the system.

By minimizing the losses, you get to hear more of what the system is truly capable of. So long as you have a good system, you should like what you hear. If you don't have a good system, you'll get to hear just how bad certain aspects of the reproduction really are. Don't blame it on the low impedance speaker cable though, because it's not an active part of the reproductive chain. It's simply a conduit for the signal that already existed. Now you get to hear the system, warts and all. Sean
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Downunder: Nordost's "design formula" for cabling can work well for interconnects, but it is simply electrically out of place for speaker cabling in a perfectly balanced system. This is not to say that their speaker cables are horrid, but that they definitely introduces specific sonic characteristics into a system due to the electrical characteristics that Nordost chose to work with.

Let's look at a circuit diagram of our system as a whole. Common sense should tell us that combining an amplifier with an output impedance of less than a tenth of an ohm ( most SS amps ) with a speaker that is roughly eight ohms and connecting the two with cabling that is well above 100 ohms would skew our electrical results. In raw figures, it would look like .1 ohm ( amp ) into 100+ ohms ( Nordost ) into 8 ohms ( speaker ). Obviously, there is an impedance bottle-neck which would create both a mismatch and a lack of proper loading / current flow characteristic. This is exactly what happens and the end result is a reduction in low frequency output, which is current driven.

That lack of current "chokes" the low frequency signal, which in a system that is already on the heavy sounding side, tends to balance things out. That balance is not achieved due to increased control ( exactly the opposite ), but due to a lack of signal being introduced into the speaker to excite that specific problem.

If the speaker is putting out too much bass, simply reducing the amount of signal fed into it helps to achieve a more linear output. This would be equivalent to turning down the low frequency controls on a preamp or equalizer. On the other hand, using an amp / cable with an "iron grip" wouldn't allow the system to over-compensate for a non-linearity in the output of a speaker. It would simply deliver the signal to the speaker which would excite it into the non-linear output of acoustic energy that it tends to naturally display. In effect, the only way that an amplifier could compensate for the non-linear output of a speaker would be if the amplifier itself was non-linear and / or using some type of active circuitry to monitor the output of the speaker itself i.e. "motional feedback".

With that in mind, i've always said that Nordost speaker cables would work well with speakers that lack proper damping in the low frequencies and / or are soft sounding on the top end. They tend to highlight a specific section of the audio spectrum, but do so at the expense of the opposite end of sound. This would explain why you're having such good system synergy with the Valhalla's, the CJ and your Vienna's i.e. both the amp and speaker cabling are somewhat lean sounding / lacking in low frequency capacity, which helps to balance out the abundant "warmth" in the speakers.

The end result is that the system sounds balanced, but in the long run, there really is a "scientific" & "mathematical" reason as to why it sounds as good and / or "tonally balanced" as it does. Had you been using different speakers, you're results would have most assuredly been different in terms of the cabling & amp that you thought sounded best. In your system with your specific componentry, i'm sure that the Nordost's don't sound lean. Then again, you're not just listening to the Nordost's, but to the entire system as a whole.

This is why i've tried to teach that one needs to pick their source, speakers and speaker cabling first, then look at the rest of the system from there. Speakers are the toughest choice, as they involve proper room loading conditions, specific placement considerations, various spl requirements, etc...

Maintaining a high level of electrical and sonic accuracy at both ends of the chain simply means that the components in the middle need to maintain that accuracy with the least amount of distortions. After that, the only other variable involved is how much power one needs in order to properly drive those specific speakers in that specific listening environment. Choosing speaker cabling that is electrically compatible with the speakers and loading characteristics of the amp simply allows one to hear more of what the amp and support components can deliver while minimizing one more variable in the equation.

This approach may not be as fun as the "trial & error" approach of buying and trying a million different speaker cables and / or components, but it is surely more consistent and far less costly. Whether one likes the "electrical accuracy" that such an approach brings with it is strictly a matter of personal preference and how good of a job they did in choosing the source and speakers. That takes into account that the other parts of the signal chain aren't extremely lossy or introducing their own distortions into the equation. Sean
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PS... It should be pointed out that the above comments are specifically discussing Nordost's speaker cabling and their electrical characteristics, not the entire line of Nordost products. As mentioned above, the electrical characteristics of their interconnects shouldn't present a problem / introduce gross electrical errors into most systems. That is, so long as the nominal impedance of the cable "somewhat agrees" with the nominal input and output impedances of the mating components. I'm not familiar with the design of their digital, video or power cords, so i can't comment on those.

As is usual, i'm simply sharing my point of view on the subjects being discussed. How much weight or validity one wants to assign to my comments is strictly up to them as an individual.

Mr Bill: I mentioned a specific value for speaker cable impedances i.e. less than 20 ohms. There are quite a few cables that achieve that figure or better. The first that come to mind are Goertz, Electrofluidics, which is a generic clone of Goertz made in the UK, several different Kimber models, Empirical Audio, etc... Whether or not all of these cables meet other particular electrical criteria or are to one's liking is another matter.

Downunder: I re-read your above post and found my mistake. You specifically mention having the Valhalla's as interconnects, but you did so right after being critical of the Transparent speaker cables. I leapt to the assumption that you had replaced them, along with the other cabling in your system, with Nordost products. My mistake and i appologize.

As to the CJ SS amps that i've heard in the past, they typically tend to sound somewhat soft in the deep bass, a little elevated in the warmth region and slightly soft and smooth up top. It is a pleasant presentation albeit somewhat reminiscent of a "moderate" tubed sound. In effect, they are "lean" sounding to me as they don't have the commanding low frequency response that one expects from a large, high powered SS amp. In effect, an amp without "slam" is "leaner" than an amp with great low frequency slam and impact. I guess it is a relative term with varying degrees, but i could see how one could be confused by my terminology.

As to what reviewers use or endorse, does that make the component or cabling "good"? Maybe, maybe not. It all depends on the reviewer and what they were discussing. I've used / heard many products that reviewers think sounds good and i know them to be horrid performers, both electrically and sonically. To be specific, the Valhalla speaker cables may work quite well with poorly designed vented speakers that lack damping, of which there are 10x more available than there are good speakers on the market. As such, mating a coloured cable with a speaker of the opposite colouration might help to balance things out.

As to the Vienna's being "fat", if you read a review of one of their products in Stereophile and their later comments about those speakers, they specifically state that they had a very hard time positioning these speakers in-room when trying to achieve natural sounding bass. I'm not making that up, nor have my own ears deceived me when forming a similar opinion of their product line after listening to them on several different occassions. When first hearing them, i thought the bottom end sounded very reminiscent of a few different Legacy models i.e. heavy bass peaking with a complete lack of definition or articulation. Sean
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I'm not doubting that the JC-1's are a nice amp, in every respect. It has a very rich lineage in terms of the designer, circuit lay-out, voicing and parts quality used.

Having said that, when one hears a well designed low / no global feedback design that is well implimented in a system, there's just something about it that a higher global feedback amp seems to lack. You can call it "liquidity", "air", "separation of notes", "life", "sparkle", "midrange palpability", etc... but it is both noticeable and quite audible.

This is not to say that there aren't amps out there using high amounts of global feedback that produce these sonic attributes, but to say that i've never heard one that could deliver such things in both the manner and quantity that a low / no global feedback circuit does. In effect, you CAN have a very good tasting cake, but that doesn't mean that the cake couldn't be just a bit better in certain areas.

Having said that, not everyone likes or desires the same attributes in a cake OR audio gear, so the bottom line boils down to personal preference. Many times, personal preference boils down to what one has been exposed to at the time and / or the listening ability of those involved. As one's experience and education evolves, so does their ability to judge the products on a more even footing. Not only does this change their perspective, it also changes their criteria for what is best suited for their needs and desires within the confines of their system.

Having said that, at this level of performance, we are splitting hairs here. It is kind of like admiring the shimmer and glow in the hair of a beautiful blonde, the rich dark contrasts of a brunette or the fire and sheen of a red-head. All have their drawing points and can be beautiful, yet each is different in their own way. When you find the one that you like and admire the most, who can tell you that you should like one of the others better? While it is true that variety is the spice of life ( don't we all wish??? ), finding something that you can live with over the long haul is both comforting and enjoyable.

Kudo's to you that have done so and are comfortable with your decision. Beauty is obviously in the eye ( and ear ) of the be-holder, so don't take anyone else's criticism of what you have or desire too seriously. If one product ( or human being ) were "perfect" for all situations, there would be no need for the amount of diversity that enables us to make the choices that we have open to us. No product ( or human ) is created equal in all areas, so we have to pick and choose the traits that are most important to us.

As i've always said, buy and use what you like. You're the only one that's going to be using & listening to it on a regular basis. Whether or not i or anyone else like it is trivial at best. Most of us that visit here regularly realize that, and we are simply comparing personal notes & "shootin' the breeze" : ) Sean
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