"D" amps, general discussion who's 1 and why?

There sure seems to be allot of continued "BUZZ" regarding "D" amps. I am reading more and more SET/Tube users and lovers actually recommending and using them.

So what are your thoughts.
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Really? I'd love to hear from those who've gone from SET & other tube amps to "D" amps and what they like about the change. I think it's magazine/ad generated hype.

My naive opinion is that they are cheap & powerful, good for bass in a bi-amp situation, etc., but they don't sound like music. They could be revolutionary for applications like boom boxes, in televisions, etc where teeny ss amps are needed. Nothing sounds as crappy as the sound in my Panasonic flat screen tv. Cheers,
There's nothing cheap about Rowland, Spectron and a few others. BTW, these are not "digital" amplifiers, they are merely Class D.

The people that like these amps tend to like neutral, unstrained, clear sound. They demand very fine source components. If you want some added warmth to offset some glare from your CDP or cables, then you probably need to look eslewhere. Some people just want warms sounds and they should also look elsewhere.

Ericjcabrera, you and I have a similar views regarding digital amps. When did you last hear them in your system, they seems to have come along way in the last year or so from when I last heard them in my system from what I am reading from others which I have to say intrigues me.

Sbank, there are few that have gone from Tube amps to specifically Spectron amps latest version. There is a lengthy but very good review on Audiogon from one owner and the amps he compared to which are very respected, there are others also and this is why these have peaked my interest and want more thoughts from others regarding this. When you say they are cheap, what do you mean? because they are by far inexspensive. The gorgeous looking Jeff Rowland 312/301 mono blocks leading the pack I believe cost wise and then the Spectrons come into play arround 14-15K for mono blocks with no upgrades which will even drive them up higher in cost. Have you actually listened to any in your system.
I have gone from Rogue M 150s and various solid state class A and class A/B power amps to class D.

My first foray was with PS Audio GCC and GCA series, the GCA 250 had a level 2 mod from Underwood HiFi.

I then bought the Wyred 4 Sound SX 500s to biamp with the GCA 250. I sold them both and replaced with a W4S MC 250/500.

I chose W4S because Rick Cullen has been building class D for various companies. Also, he has a strong reputation as a modifier. Putting 2+2 together, he brings quite a bit of knowledge to the class D game.

Like all components, W4S amps are power cord and interconnect sensitive. I just replaced a Tek Line micro Reference Xtreme power cord with their Reference. I am shocked at how much better the Reference is over the already impressive micro Reference Xtreme. Definitely worth the extra $250 when used with the W4S amp.
I have a D-Sonic class D amp which replaced two class a and a/ab amps and I am astounded by the incredible dynamism, details, neutrality, etc, etc... I never heard my system sounding so realistic with true dynamics and details from top to bottom.

The fact that thanks to ICEpower modules it is possible to build amplifiers with real power (and making our planet greener) with perhaps less money (and I wouldn't call my 3K amp cheap by pop standards) doesn't mean that it doesn't deliver high quality.
I just don't understand why so many people are carried away by suppositions on a product that they didn't even listen to it, but I do understand if any of you would prefer a different type of sound.
If you do like neutrality, well there it is, to me it perfectly matches my power hungry, warm sounding Vienna Mahlers. I never heard them sounding so musical. I welcome technology advancement.
I talk to customers daily and generally speaking those most critical of Class D amps have never heard a good example. Some have and that's fine; at least they've given a listen.

Many are skeptical and unwilling to accept new technology when in fact a Class D amp would suit their requirement remarkably well.

Go figure.

Personally, I prefer SET. However, the number of speakers properly driven by SET amps make up only a small percentage of available products.

Dealer disclaimer.
Tweak1 hit on the head. Anyone venturing into class D have to rethink their system strategy. Class D transmits everything in your chain including gremlins emitted by your cords you don't even know are there before.

Same goes for digital sources. I have proven oversampling and upsampling are injurious to the signal. This, again, will not be so evident in conventional systems. Only in class D and fine SET systems do this truth bare out. Although the non-digital filter loaded DACs are few, the rewards using them is simply mind boggling.
When I said "cheap" what I meant was that on a watt/$ basis compared to most tube amps, and SETs in particular, you get more power for your money with Class D amps. The point being that they can be used with a wide variety of speakers vs. SETs, a point raised above.

I've heard several class D amps, including the Rowlands and NuForce at shows, but none at home. Nothing I've heard yet has tempted me to audition one at home. Perhaps that will change as the technology evolves.

I am not surprised to see many recommendations for Spectron, as that seems to be the one that's got the most buzz here and elsewhere. Looking forward to hearing it. Cheers,

No deHavilland lover is going to like Spectron, nor vice versa, so save your time Spencer.

Class D amps, I remember way back in the 80's when I had a pair of IRS Infinities top of the line speakers and these were the amp design and provided with the speakers to actually drive the base tower units, this technology seems to date back some time now.

I did some listening evaluations about a year ago with Bel Canto 1000's, Jeff Rowland 501's and Nuforce mono blocks, forget the model number now but found they all did nice things but to me just were no musical enough or involving compared to mosfet design but from all the "buzz" "D" amps all seem to be improving and evolving. The threads I constantly read about Spectron specifically more so than others, allot of actual tube owners going with this product. There seems to be only a handful of Jeff Rowland in comparison and when you read what they have compared to it just does not seem to be in comparison.

Audiofeil, you being a dealer who gets to dabble with different pieces and you mentioned your preference is SET so what's your take on them?
What product do you believe to be on top of the class "D" food chain list and why.

I have spoken to a few and they have mentioned to me saying I should have another listen to Bel Canto for example. I'm still looking forward to hearing Spectron mono blocks but just can not get arround my head dropping the type of money they are asking for them mainly due to the fact of my past memories and experience of the other class "D" product I had bought and being far from satisfied and at only a fraction of the price. Spectron did offer a 30 day trial not sure if they do anymore but anyone knowing class "D" product and the break-in time is very long so that just doesn't work.

I don't know anything about spectron, so i can't comment on it. But, I'd like to trust a bigger company like B&O that has larger budgets for reseach and the capability of marketing products at a lower price. That doesn't necessarily mean that the product should be of lesser quality (see Denon and alike). My understanding is that IcePower have created several levels of modules for different applications.
I think they are very speaker dependant. My one audio bud, listened to the Bel Cantos (he loves their DAC) and he found them unsatisfying and went back to his big class a/b amps. I have a pair of Nuforce SE9s and they work wonders with the Mbl 101Es. But that's just one application. I think you must try them yourself and carefully work them into your system with cable changes, tweeks, amp stands, etc. to get the magic mojo.

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B&O and their government spent a ton of money developing ICEPower. That gets you a certain base level of acceptable performance. Spectron, Rowland, Bel Canto and others enhance the base modules and move you into high fidelity. How high is debatable, but I happen to think that it's true high fidelity.

There'll always be people that prefer SET over anything else. There'll also be plenty of people that prefer high end applications of ICEPower over SET, Class A or MOSFET. There's room for all of us and, thankfully, plenty of choices for all of us.

I believe that you should pick the best speaker that you can afford, that is suited to your room, next buy the best sources that you can afford and finally match it up with an amplifier that works well with you speakers. The speaker choice is certainly a personal preference, then, by default, most of the other choices become personal preference. If I don't want tubes in my DAC, that shouldn't prevent someone else from seeking a tube-DAC.

There's nothing hard and fast about Class D and, ultimately, we need to listen for ourselves and chose according to our personal prejudice and desires.

Breuninger, very interesting indeed. What is the rest of your set-up consist of with the MBL's including IC's, PC's and SC's. I thought I read you were using Jadis 500 mono blocks.

I actually have the same speakers as you but when I was doing the evaluations of "D" class I was doing it with Eggleston Andra 2's, Virtual Dynamic Genesis cables threw out.

Ericjcabrera, which current models and what did you go with and why, what differences did you find.

Dcstep, you own a Jeff Rowland 500 Continuum Integrate have you done any listening comparisons with any other similar designed amps such as Spectron, if so what's your take. I really like the gorgeous look of Rowland product.
Spectron and Nuforce don't use the B&O module or anybody else's for that matter. They use their proprietary module.
Sbank, Philefreak is a die hard SET amp guy.

Philefreak, I know you responded to the other thread but you should add a little more here about you experiences with class "D" and specifically your thoughts of Spectron product.

Philefreak that was great info. you gave in the other thread, I have heard from others that going with mono blocks the difference again is major, any thoughts.
My best friend has built his system around set amps with an
analog front end. I built mine with class "D" amps and a
digital front end. We listen to each other's systems all the time. It is amazing how similar they sound. I will have to say I did not like the sound of my "D" amp after i first purchased it. They do require a lot of playing time to break in.I found using balanced interconnects all the way through my system also helped.
Tan43, kindly list in detail your system set-up and your friends.
I first became intrigued about Class D after hearing that Von Schweikert and Gallo were using the Spectron Musican II to demo their products at trade shows, with generally better sonic results than many rooms showcasing costlier gear. After reading a few reviews, the Spectron Musician II became my first entry into the low end of the high end, and my results have been very impressive. The first combination of the Spectron and Totem Forest speakers provided one of the fastest, most dynamic and detailed setups I have ever heard, and very, very impressive imaging and soundstage as well. Exactly as advertised in reveiws of the Spectron.

I recently decided to upgrade speakers, which resulted in my taking my CDP and the Spectron to a dealer, where I played it with Sonus Faber Grand Piano Domus and Dynaudio S3.4's. I thought both systems sounded fantastic. To my ear, the Spectron sounded as good as, but different than, the BAT tube amps that had been driving the Dynaudios. Not as warm but faster and more detailed. My impression was that I was hearing more of what had been recorded in the studio with less coloration. Others might disagree or simply subjectively like the other sound. The Spectron ran circles around the Moon Audio integrated that was driving the Sonus in the store. The dealer seemed genuinely impressed.

During my speaker search I also spoke to high end dealer of lines like Audio Physic, Silverline, etc, who confided that he is using the current Spectron Musician II Mk2 SE in his personal system to drive MBL's.

I ended up buying Dali Euphonia MS 4's, so I have now heard my amp with four different sets of speakers, some more revealing than others. I never heard anything approaching a bad match, frankly just different degrees of excellence.

My Musician II is at least two generations old, and the technology has reportedly advanced a great deal in the last couple of years. Listen with your ears and with no preconceived notions. I have nothing against other technologes, and I am not trying to be a cheerleader for Class D. I truly don't understand why anyone would become ideological in this hobby about a certain technology over another.

If you have the time and the gear is available, I encourage you to listen for yourself. If the sound of Class D is as good or better than competing technology, then you can also start to consider that these amps generate literally no heat, that there are no issues of tube life or possible damage or degradation, etc, etc. These are just incidental benefits to a product that, to my ears, has outperformed most everything I have heard in absolute terms, but especially dollar per dollar.

My recent, limited experience with a Class D amp mimics quite closely that reported by several others above.

I bought a bel canto 300 to use in a second system. For fun, I tried it in my main system (Dynaudio S 3.4, Rogue 90 tube amp, Rogue 99 tube pre, Cary 303/300, Acoustic Zen cables). My overall impression was that it really is a very good amp, warm and musical across the board with a remarkable amount of detail in the mids.

After a few days of pretty careful listening, I decided the class D amp gave up depth in the harmonic overtones relative to the tube amp.

I'm not sure if that is standard audiospeak, but it is standard babble among instrument builders. When you strike a note on a guitar (or any resonant object, really), you hear the primary note loudest--the fundamental--but you also generate a series of higher frequencies that reverberate and these provide considerable depth to the sound. Guitars for some types of music (say, flamenco) and built to minimize overtone structure and others (say, for Celtic) and sometimes built to enhance it.

I decided that the bel canto offered a strong fundamental but considerably less overtone structure that the Rogue. Still, the differences were slight and I still like the amp a lot (and love that's it's "green"). But if you're after complex overtones, it might not be ideal.

I do appreciate the my 300 is not bel canto's best, and I suspect some more expensive designs or different implementations may be quite different.

Info on overtones: http://en.wikipedia.org/wiki/Overtone
Dev, I've heard the Spectrons and the new Bel Canto and think that they deserve serious consideration. I'm feeling no need to replace my Continuum 500 and I'm finding it's 1000 watts into 4 ohms and very refined pre-amp section up to the task of driving my speakers and managing my system.

Running the Spectrons bridged as mono-blocks yields astonishing power without sacrificing anything in detail and refinement.

I have not heard the Spectron or Bel Cantos in my system, but only in show systems, but I heard enough to tell me that they're making contenders for serious system.

The cosmetics of the Rowland are amongst the best for my taste. Those cosmetics are backed up with solid, close tolerance chassis design that's more than a pretty face. IMHO, you can't go wrong with Rowland, unless you're expecting your amp or pre-amp to warm up the sound. If you like neutral, transparent and dynamic, then you need to look at Rowland.

I can make my class D system sound sublime or miserable depending on what I hook my amps up with. I know, because I have done it time after time.

Every time someone brings over a glorified digital filtered digital source, the sound closes up, harmonics are lost, proper gradual decay becomes severely truncated.

Non-shielded power cords will strangle the sound. On the flip side, unnecessary insulation on speaker cables will transmit white noise.

Use ordinary power cords, good ol' hose speaker cables, and a wonder SACD player, and you have a class D disaster in the making.
Muralman1 said:

"Every time someone brings over a glorified digital filtered digital source, the sound closes up, harmonics are lost, proper gradual decay becomes severely truncated."

I'm not understanding what type of source you refer to. I see that you have a PS Audio Lambda, so you're not anti digital. (I loved my Lambda until the nylon gears on the drawer stripped after many years of usage). Could you give an example of a source that you're speaking of?

I'm using a Playback Designs MPS-5 SACD player with my Rowland with fantastic results. Of course, there are many differences between PS and Rowland (beside the 60-miles between their shops), so they're going to potentially react differently to same sources.

I DO agree that you have to be careful with ICs, PCs and speaker cables with Class D and you need to be aware of RFI and EMI when placing components around these devices. Chassis design is critical to minimize interaction, and some Class D amps are more prone to interaction issues than others.

Dcstep, as you know, the Lambda is a transport. Mine has a new wheel. Also,
it has been given a big lift in sound by Henry Ho. My DAC is an Audio Note
2.1. This too has been highly advanced with updated electronics. The DAC
has 4 NOS tubes. For tube lovers this is very essential. The tube's
spaciousness and natural delivery is faithfully preserved.

Every over and up sampling player sucks the stage both horizontally and
vertically. Also, all harmonics vanish. The difference is striking. I have had a
Modright tubed Sony SACD here, and with the same negative results.

The tubes do no good in resurrecting the SACD's performance. The digital
filter damages the tube's good qualities.

The why is easy to understand if you have any knowledge of the quantum
mechanics theory. The complete signal is an ever changing pulse of great
complexity traveling near the speed of light. There is no way a circuit can
differentiate and deftly cut out the, "distortion," without taking music
nuances with it. I can prove that here.

I think that applying quantum mechanics to digital reproduction is quite a stretch. Please share the proofs you mention with us.

BTW, the DSD encoding scheme used on SACD does not use a digital filter on playback. That's one of its advantages.

Also note that almost every digital recording made in the last 15 or so years was made with a delta sigma oversampling A/D converter, so your digital sources (CD and SACD) have already seen one round of oversampling and digital filtering before they get to you. Since you're hearing something musical from your DAC, it would seem that oversampling and digital filtering are not per se robbing digital of musicality.

I think that comparisons using "every", "always", and "never" are suspect. The world is more complex than that.

My $.02
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steidguitars, your point is interesting. I wish that our statements were followed by links to reliable sources on regular basis.
But the problem here is that you are assuming that class d is not able to play overtones and that has no basis on real facts.
It's possible also that class d is so faithfull that plays back recordings without artifacts that where not intented in the first place or you are confusing overtones with distortion - class d is known for lack of distortion introduced in the signal. this is pure speculation.
As a relative latecomer to these conversations, it appears that this discussion of oversampling has some history to it. I run a Cary 303/200 into the Spectron. The Cary has an oversampling button, and after playing around with it for a while, I cannot believe how spot on is the language used by Muralman: "the sound closes up, harmonics are lost, proper gradual decay becomes severely truncated." It is as if every instrument has been put through heavy handed gated compression in the studio. All the "natural-ness", for lack of a better word, is removed from the instruments.

However, this being my first experience with oversampling, I attributed it to the CD processor, and not to the amp. Does Class D exaggerate this effect in a way that other amp topologies would not? Whatever the cause, I listen exclusively in non-over-sampled mode now.
I auditioned the Bel Canto Ref 1000 mk2 mono-blocks recently and was absolutely astonished with their performance. Use a product like this with a tube amp of your choice and i think widespread appeal will be found.

Speaking with the dealer i asked him how sales we going. He was very pleased with his sales noting that most customers were trading in their LARGE class A power amplifiers from the likes of Krell, Boulder, Mark Levinson etc for the Bel Cantos. When i asked him why - he said its simple, 1. Class D takes it less real estate, 2. Class D is more efficient and 3. When compared one one one with their existing amps the owners could not discern much difference.

Interesting, and perhaps pause for thought for those that rubbish this class of amplifier.
Muralman1 said:

"Every over and up sampling player sucks the stage both horizontally and
vertically. Also, all harmonics vanish. The difference is striking. I have had a
Modright tubed Sony SACD here, and with the same negative results.

The tubes do no good in resurrecting the SACD's performance. The digital
filter damages the tube's good qualities."

Thanks for clarifying. Ok, I see where you're coming from, but I disagree. My Playback Designs MPS-5 plays RBCD or SACDs wonderfully while using an upsampling scheme. Many people have now heard the PD and consistantly consider it one of the top players available.

When tubes are suggested to address a digital source problem, I grow suspicious. Generally, I think that tube lovers should stick with all-tube pre/power systems; however, mixing a tube pre with SS power amps, including Class D, can work very well. There's usually a reason that people turn toward tubes and, IME, it's often to offset a weakness in their sources.

Jswarncke, the answer is yes, and no. It isn't that class D exaggerates the effects of distortion graters, they unveil the sonic damage that has always been there.

You should hear the cable talk on my system. That is another class D revelation.

Ghostrider45, I use the Quantum theory because it fits. My speaker cables are extremely thin ribbons. The music signal in all it's fruition slips through without inhibition. We are talking about the very small.

I can use words like, every, always, never, because I am talking about events witnessed on my system. I would be lying otherwise.
Maab, what I offered up was my listening experience in my system. I did wonder, however, whether with proper equipment if I might be able to actually back up my impressions with measurements.

But then I decided to listen to music instead. ;-)
Class "D" seems to most defiantly becoming more and more popular. The advancement of the sound qualities constantly improving.

There is always going to be different opinions as is life.

I'm constantly reading and hearing from others that they are going with some sort of "Class D" amp product and replacing some pretty well known and respected pieces and this is why it has really peaked my interest.

I guess I'm going to have to put behind that past year I had which was a disappointment and try again.

Now comes the decisions, which one do I want to try first and why, any opinions.
I can't find what your pre is Dev.

If you'd be willing to forgo the pre, I'm thinking that you should seriously consider the Rowland Continuum 500, which gives you a great pre, power factor correction and most of the circuit of the 312, all for much less than the cost of a Capri/501 monos/PFC combination.

If you want to stay with your pre, then consider the 501s PLUS Power Factor Correction. Try to run everything balanced and see what you think. With luck you can find some used 501s here on A'gon and add PFC.

Few of us need the power of the mono Spectrons, but, if you do, there's very few substitutes right now. My experience with the Continuum shows me that huge reserves of power is a good thing, at least when the power is clean, transparent and non-punitive (as with some older SS amps in other classes).

Muralman what do you mean about "cable talk" on your system. I note that you are using cheap solutions - care to elaborate on the thought behind it all?

You can see what I am running on my system link. I will tell you this, if there is any noise or distortion in my system, it seems to be way blow the threshold of my hearing.
Jswarncke, I auditioned Cardas Golden Reference, and Jenna Labs over the same long weekend. At the time I was using Speltz Anti-Cable. The Cardas was the worst sounding of the two visitors. The Jenna less so. They both exhibit a great deal of hiss. That is the bleeding into the signal charges stored by the insulation.

On my class D system, this was an easy read.

Hearing what great results folks I know in Europe using thin ribbons insulated in Teflon, I decided to meld the two cable types, Anti-Cable and the ribbon. I knew I didn't want the insulation.

Yes, it is cheap. Try it. BTW great room!
Dcstep, pre-amp I'm currently using is a Audio Research Ref3.

What specifically is the Power Factor Correction you are referring to.
Ok, the AR Ref3 will be a good match for 501s. You might read Guidocorona's review of the Rowland Capri, where he moved from the Ref3.

PFC is an interface with the mains that Rowland uses to present an even load to the mains and convert the AC line to 380 Volt DC for the amps. It's designed for certain recent Rowland models, including the 501s. It's built into the 312 and the Continuum 500, but can be had as an add-on to the most other current Rowland products. (The PFC units that Rowland uses were originally developed for commercial cell-tower equipment by cell phone companies).

You need to talk some directly with Guido. I have no direct Ref3 experience, but he can discuss the pros and cons of moving away from the Ref3 to Rowland, since he made that move it.

Cardas Golden Ref works well with Rowland, giving no "hiss". I don't use it, but I've heard it in Rowland systems a lot. There could be a number of reasons for the differences noted. For instance, not all Class D has managed RFI and EMI as carefully as Rowland and some others. Chassis design for optimal isolation and ground management is critical with Class D.

Muralman1, you said:

"Ghostrider45, I use the Quantum theory because it fits. My speaker cables are extremely thin ribbons. The music signal in all it's fruition slips through without inhibition. We are talking about the very small."

Cables are many orders of magnitude too large to directly exhibit quantum effects. You need to get into the subatomic realm for that.

I don't doubt that you're getting good results, but I believe many of us are also getting great sound through different paths. We don't need to mis-apply real science or invent pseudoscience to explain our successes (and failures).

It's all about good engineering and open minds.

Enjoy the music!
With all the mention of the Rowland products I'll chime in here with my experience. I use the CONCERTO integrated with outboard PC-1. Amps before this include the McIntosh MA-6900, Cary Cinema 5 (excellent by the way), Rowland Concentra, and McIntosh MC-300. I've had the same speakers across all of these amps save the MC-300. Speakers are Tyler Linbrook monitors.
The Rowland Concerto is superb. Compared to all of the other amps I've had it loses nothing. Detailed, not cold, not warm, excellent noise floor (low) and dynamics. I will say that when I added a Shunyata Hydra things improved even moreso. I have read here from other posters the same experience. Not sure why, but it did. With the PC-1 and Hydra, the Concerto is fantastic. I have tried the Concerto without either the PC-1 or the Hydra, and it's still 95% (speculative enumeration!)of the way there.
I recently tried this system with a pair of Proac D25's, and the sound was similarly fantastic in all the areas you would ask about - soundstaging, midrange, etc, however the treble was too 'hot' for my tastes. I breathed easier when I put the Tyler's back in. Now lest someone say obviously the Tyler's somehow are not up to the task, I'll add that the last head-to-head I had in my system was the Harbeth SHL-5, which did NOT have any bright treble issues with this amp. It was truly spectacular. (My post is here elsewhere on the differences between the Harbeths and Tylers). I have yet to find a speaker that I have auditioned (save some bigger Wilsons and ML Summits) that did more for me than the Tyler's, and many less. Anyway, as far as the class D amps in my experience, I recommend them. If mine was cold, analytical, bright, or not 'full bodied', I could not live with it.
Criticisms? People have said they work better with some speakers more than others, that they could use a 'good line conditioner', and they may have a flatter soundstage from front to back than tube amps. From my experience, I could not argue with any of these points. However, given my experience with amps the Rowland is still the best I have enjoyed.
Hi Dcstep, Guidocorona and I have communicated prior and I have been following the Criterion 2-chassis battery pre thread.

I actually have interest in this pce along with the 301 mono blocks. I have not found anyone who actually owns the 301's to date. Reading the Rowland site and spec information regarding the 312 stereo Guido uses and the 301 mono blocks I have to say it has left me a bit confused and wondering are the mono's the preferred way to go. My set-up is not stereo friendly so unfortunately I need to go with mono blocks. Are you aware of anyone using the 301's or have you heard anything about these.
Dcstep, How do you explain why neither the varnished Speltz Anti-Cable and my own virtually naked ribbon SCs have no hash issues? And why did the more lightly insulated Jenna sound less distorted than the Cardas?

Henry's amps are housed in a thick aluminum plate case. There is heavy internal shield separating the power supply from the module. My ICs are naked and long. My DAC and transport are obviously unaffected by any spurious ICE radiation.
Ghostrider, I do not mean to have my ribbons held up as a measure for the signal size. I just noted that it carries all frequencies with ease. The music signal is intensely complex. Timbre, dynamics, and musicality are a sum of an unimaginably complex wave particle pulse. I don't care how carefully a chip is designed to only cut out distortion, it is not going to be able to accomplish this task without taking out the most delicate of signal. Like I said, I can probe that here, and I have done so time after time.
Muralman1, the H2O M250SA are very interesting product also, you just recently installed the H2O Fire preamp and seem to be enjoying. Have you done any direct comparisons to Rowland, Spectron latest version, Bel Canto latest version.

If so what are your thoughts.

I was just chatting with someone today and the new Bel Canto MKII is suppose to be a substantial improvement and right now allot of talk.
Spectron did offer a 30 day trial not sure if they do anymore but anyone knowing class "D" product and the break-in time is very long so that just doesn't work. Previous from above,,,, ,Yes and so did Bel Canto,then they went to 2 weeks,You sure cant evaluate these amps in 2 weeks no way no how.What do you think a manufacturer is going to say,of course they will say new and improved.These amps are so system dependent its almost funny and funny not in a good way.So in essence since a 2 or 4 week trial really isnt very revealing what is a person supposed to do?It just comes down to individual choice,but if you think these amps are going to part the red seas,you would be sadly mistaken.
Muralman1, I can only comment on the Rowland Cardas GR combination as working very, very well, with no hiss. I don't know what's wrong with your PS Audio that would cause a hiss. On the Rowland I've only heard it in balanced mode with the Cardas. There's similar no issues with Analysis Plus Solo Crystal Oval ICs, which I use, in balanced mode, but I've tried in RCA configuration with no issue.

Oh, the longest Cardas GR that I've heard is around 6-feet. You say yours are "long", how long? (I use 20" Klotz XLRs all the time as condenser mic cables and have no issues. I'll have to throw a pair into the audio system to see what happens).