What Is It About Spectral That Creates Believers?

[DonH50]

How they accomplish that (essentially power factor correction) without knowing the load (speaker) characteristics escapes me... Do they make certain models for certain speakers, or types of speakers?

 

[Mobiusman]

Thanks for the effort to educate me. It is not easy, but the proof is in the listening.

The technology appears real and deep, thus hard to grasp and easily explain (much less copy) therefore you should still read the white paper for a layman's summary. In addition, the patents cover a variety of problems they are attempting to solve. I'll dig up the analysis from over a year ago some time next week, but for the time being, briefly, the most recent patent is mostly about keeping the voltage/current relationship as close to a perfect -90 degrees at _every frequency_ or more accurately at as many frequencies as possible (and probably as many harmonics as well), while avoiding crossover interaction as possible. They call this the power transfer or some such. How much of that is real science and how much voodo is partly left to the ear. But I am mostly convinced of their claims, and the results speak for themselves, as you also witnessed. Having said that, some of us also think there may be phase problems between SD and HD modes, others don't hear that with the top of the line cables - one thing is for sure, as the MIT manual says, the ultimate final setting will be system dependent; therefore, I think there is more than meets the eye (e.g. phase issues may perhaps be a result of crossover interaction). In the end, there is never a free lunch. However, what I consistently observe is that just about anyone will first claim they have heard Spectral systems that sound just fine with other cables, then pay attention to the manual, then start digging in. You are probably beginning to better appreciate the sophistication of these pproducts (not saying others aren't better).

I'll try to gather my thoughts spread around in various threads in one post later on.

 

[Mobiusman]

Help me figure out how to upload a picture and I will gladly post a picture or two.

Never mind your system, I want to see a picture of your girl friend that you keep yammering about!

 

[mep]

Save a picture to your desktop. Hit reply on WBF. Look at the tool bar up top. Click on the icon that is third from the right. When you hover your mouse over the icon it will say "insert picture." It should be gravy from there.

 

[Mobiusman]

While I feel a bit weird about doing this, I guess I owe this thread an image of the woman I have been talking about.

 

[Al M.]

Great thread.

What Is It About Spectral That Creates Believers? The music that comes out of the amps.

I am a tube guy, always have been. My own amp is a set of Audio Innovations Second Audio push-pull triode monoblocks (2 x 15 W), originally designed by Peter Qvortrup, now lead designer of Audio Note, but an expert in Connecticut turbo-charged it with new and more powerful components beyond recognition over the original in terms of speed, cleanness of sound, lowering of noise floor, and increase in dynamic headroom -- the amp basically has been re-built from the ground up, bigger (at least in terms of capacitors and rectifiers) and better.

I did admire the old Spectral gear 20 years ago for its transient speed and natural timbre, but I did not like the dynamics. Macrodynamics were off and in particular I did not hear reasonable microdynamics (on Avalon speakers). Yet in my opinion the recent Spectral gear is a fundamental, spectacular technological breakthrough in music reproduction. I am an absolute Spectral convert after recently having auditioned the Spectral DMC-15SS pre-amp/DMA- 260 power amp combo in my own system, comparing it with my amp running on the digital volume control of my Berkeley Alpha DAC 2.

Twenty years ago and, judging from the still ongoing and raging debate, until recently, there appeared to be that unbridgeable divide between solid state and tube amps, with each type of amplifier being able to do some things that the other type simply couldn't do. No more. The Spectral amps have now bridged that divide, and obliterate the distinctions between solid state and tube amps -- they are just supremely natural sounding devices of music reproduction. In particular, the DMA 260 excels at microdynamics and rhythm&timing just as the best tube amp designs and implementations (including that of my amp) do, in addition to having great macrodynamic capabilities (just as my amp on my sensitive Ensemble Reference speakers). Thus it possesses just the same exciting musical liveliness and agility as my own amp, yet unlike my amp, with in the process also being able to pump out several hundreds of watts per channel, and thus being able to drive a much greater variety of speakers and to never hit a limit with mine (my amp usually never clips with my speakers, even at high volume (up to 92-94 dB at orchestral peaks), but it does so in one single -- not even very loud -- passage among dozens of CDs, thus showing some limitation; the Spectral of course does not clip at that passage). Such prowess of combining nimble, natural musical agility with a potential for great power output would have been unthinkable a while ago (high-powered tube amps tend to sound slower, thus forfeiting a potential advantage of tube circuitry) and is a breakthrough indeed -- and it certainly transcends by leaps and bounds what I had heard from Spectral amps previously.

In terms of tonal balance, the Spectral and my own amp sound identical, but they also sound virtually identical in all other respects -- microdynamics, macrodynamics, rhythm and pace (the Spectral rocks and swings just as hard as my amp does), resolution, speed and cleanness of sound, depth of soundstage etc.. There is no more tube amplifier vs. solid state amplifier, there is just music.

Perhaps my amp is a tiny bit more natural with human voices, perhaps the Spectral is a bit more natural in resolving decay of, for example, xylophone, but all this was really subtle. I thought that perhaps my amp also had a bit more body and force with cello in a string quartet, but even that may be an illusion. The day after having had the Spectral in my system I discovered that this impression critically hinges on the volume setting of my subwoofer, and I cannot at all be sure that it had been comparable in output when listening to that piece with both amps (for the Spectral I had to use the lower level line input (-10 db) of the REL subwoofer in order to avoid overload, so the settings had to be re-adjusted from the get-go). All in all, in a blind test, even an exhaustive one on all kinds of music, I would probably be unable to confidently distinguish a sonic difference between the two amps -- on my sensitive speakers, that is. On more demanding speakers the Spectral would undoubtedly win.

If I had the bad fortune that something would ever happen to my amp so that it required replacement, it would be very unlikely that I would even care to audition another tube amp; I know that mine is really special, also in terms of neutrality, and almost irreplaceable with another tube amp, except perhaps at high cost. Instead, I would probably right away order the Spectral amp, and would be living with it happily ever after.

***

I was impressed by the clean sound of the Spectral/MIT cables (loudspeaker cables, interconnects) in my system. Of course I compared both amps on these cables, since the MIT set is mandatory for the Spectral. Going back to my own Monster Sigma 2000 cables I heard an ever so slight reduction in transient speed, easily noticeable only in a few passages (tonally, the cables sound basically the same). For example, a fortissimo tremolo passage for violin in the 5th Naxos quartet by Maxwell Davies (a musically and sonically excellent recording on Naxos) shows just a slight bit of artificial electronic 'halo' and noise on the Monster cables while there seemed vanishingly little of it on the MIT cables. The difference is small; for comparison, the difference in transient speed and artificial electronic 'halo' and hardening of sound on that passage was approximately five times greater between my old Wadia 12 (modified with the faster Wadia 860 opamp) and the much cleaner Berkeley DAC that I currently own. But small as the difference on the cables may be, it is clearly audible nonetheless (at least, if my memory does not betray me, I listened on the Monster cables the next day). By the way, on the MIT cables my amp astonishingly seemed just as fast and clean in transient speed on this passage, as elsewhere, as the Spectral (yes, my amp is really fast) -- in that comparison I listened to both amps relatively quickly one after the other, so I am rather certain. My interest in the MIT cables is certainly raised -- excellent stuff indeed (I have an MIT Proline digital interconnect, by the way).

Al

 

[joeinid]

Russ,

You are a lucky man. Beautiful woman and beautiful dog. Life is good! Enjoy and thank you soooooo much for sharing your journey. I am highly intrigued with Spectral and hope to hear it next month. Thanks for all your enthusiasm. It's contagious.

 

[ack]

Thanks for the effort to educate me. It is not easy, but the proof is in the listening.

I think I found all relevant posts regarding the MIT cables and patents:

1. On the MIT patents - read from the following onwards (a great thread in itself): http://www.whatsbestforum.com/showthread.php?8737-The-cable-conundrum&p=151692&viewfull=1#post151692
2. Same thread, on the most recent patent on so-called "articulation poles": http://www.whatsbestforum.com/showthread.php?8737-The-cable-conundrum&p=151720&viewfull=1#post151720 and http://www.whatsbestforum.com/showthread.php?8737-The-cable-conundrum&p=151761&viewfull=1#post151761
3. On SD vs HD and alleged but unproven phase tricks - read from the following onwards http://www.whatsbestforum.com/showt...ral-MIT-cables&p=180658&viewfull=1#post180658
4. Finally, here's the MIT white paper I've been referring to http://www.mitcables.com/pdf/Transportable_Power_101.pdf (referenced here http://www.whatsbestforum.com/showthread.php?8737-The-cable-conundrum&p=151891&viewfull=1#post151891)

 

[mauidan]

Al M.,

Welcome to WBF. Enjoyed your post.

While you had the DMA-260, did you try running it directly connected to your Berkeley?

 

[Al M.]

Al M.,

Welcome to WBF. Enjoyed your post.

While you had the DMA-260, did you try running it directly connected to your Berkeley?

Thanks, Dan, great to be on this forum.

Running the DMA-260 directly from the Berkeley was the first thing that I tried, also because it was the easiest thing to do in terms of set-up. However, after I heard some weird noises I went the pre-amp route. It turned out that the weird noises persisted, and that they came from overloading the subwoofer through its line input. This happened in both cases: for running the Berkeley directly into the DMA-260 I had to turn up its volume much higher than with my amp because of lower input sensitivity, and also the Spectral pre-amp obviously puts out a higher signal (branching into the subwoofer) for the same reason.

Switching to the -10 db line input of the REL subwoofer then solved the problem, but at that point I had found out that the pre-amp is a very transparent source, and I then decided that at first I wanted to try things 'the correct way' (with the Berkeley output fixed at the recommended near-maximum level of 58). In the end, I had too limited time for auditioning both ways exhaustively. If I would think about actually purchasing the Spectral, I would indeed try running the Berkeley directly into the DMA-260 as well, since that would be much cheaper, not just in terms of amplification but also of cabling. Certainly this would not be 'correct', but who would argue if at Reference recordings, owned by Spectral's own Keith Johnson, they also run the Berkeley DAC directly into their DMA-180? There seems to be some internal inconsistency in Spectral's demands; yet I certainly would follow the demand of using MIT speaker cable, because there is a compelling technical reason to do so -- megahertz amplification output and all that; I don't want to fry the amp. Also, the MIT cable is better anyway than my current one, even though that one is no slouch either (I might eventually buy MIT also just for my amp).

There have been reports that plugging the Berkeley directly into a power amp, using the digital volume control, compromises soundstaging. I did not notice this with my amp; soundstage width, depth and acoustic resolution are the same as through the Spectral pre-/power amp combo.

 

[mauidan]

Al M.,

Thanks for the additional info.

A couple of years ago, I was looking at buying a new DMA-260 and drive it with a BADA. I called Spectral and their tech said bad call on both counts.

The warranty still requires the use of their cables and preamp for all their products except the Universal amp.

Guess I should have thrown caution to the wind like Russ the Mobiusman.

 

[Al M.]

Al M.,

Thanks for the additional info.

A couple of years ago, I was looking at buying a new DMA-260 and drive it with a BADA. I called Spectral and their tech said bad call on both counts.

The warranty still requires the use of their cables and preamp for all their products except the Universal amp.

Guess I should have thrown caution to the wind like Russ the Mobiusman.

Well, for his review of the BADA Robert Harley plugged the unit directly into his Spectral 360 monoblocks (and slightly preferred it to the pre-amp route). There were no 'official protests' from either Spectral or Berkeley Audio.

I think Spectral is fighting a loosing battle here. It is hard to imagine they could deny warranty given the situation at Reference Recordings; it's on their website:

http://www.referencerecordings.com/HRxSETUPS.asp

There is also a discussion at Audiogon forums:

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1260295563&openfrom&1&4#1

One person on that thread says that he used the BADA directly into the Spectral amp, but points out "As I stated in another Spectral thread the DMA-180 is not compatible with the standard MIT Oracle cables. The amp may have oscilation issue." I would indeed think that the cable issue is a much more binding one, for the known technical reasons.

 

[KeithR]

<>

 

[Al M.]

A few days ago I called up the factory and spoke with a tech about the performance of the DMA-260 (he was delighted about my positive comments) and about the issue of connecting the Berkeley DAC directly to the power amp, using its digital volume control. In the context I brought up the fact that Reference Recordings directly connects the Berkeley DAC to their DMA-180. The tech, who was a very friendly and nice person, told me that this was possible because the DMA-180 was custom modified; the Berkeley DAC does not provide the high-current output that the Spectral power amps are made for. I then asked, why would it not possible to make such a modification standard? He then replied that this was just a specific issue for which the market would be too small.

I countered that this desire for direct coupling of DAC to power amp has come up numerous times on the web, and that such an option would not just apply to the Berkeley DAC, but to any DAC with a digital volume control. I could not make him realize that this probably would, in fact, be a 'mainstream' application if made possible as option by the factory (many people apparently go digital-only these days).

I guess people on the cutting edge of things often don't pay attention to what the world around them really wants. He said that the pre-amp provides reproducible results. Yet I simply cannot understand why, for the sake of 'reproducible results' and fulfilling warranty requirements, I would be forced to spend at least 8 grand extra for pre-amp plus cables (and possibly even have a slightly less transparent window into the music than when connecting the DAC directly).

Perhaps if other people who have posted on or read this thread would call up the factory like I did, the message might finally get through to them.

 

[ack]

Spectral does offer no-preamp-required (i.e. "modified") amps called the Universal models, e.g. see http://www.spectralaudio.com/dma-160s.htm - they are deemed slightly inferior to their siblings. And it's posted before, that the non-universal amps have an input sensitivity of 100mA for rated power, while typical amps on the market are 1mA or thereabouts, and I am not sure what other preamps would offer such high-current output (the Spectral preamps output 1A). FWIW, my Berkeley certainly sounds thin going directly to the monos, and the preamp brings the missing dynamic brio to the dance.

EDIT: The other thing the preamps offer is oscillation protection circuitry (at the more expensive ones do).

 

[Al M.]

Spectral does offer no-preamp-required (i.e. "modified") amps called the Universal models, e.g. see http://www.spectralaudio.com/dma-160s.htm - they are deemed slightly inferior to their siblings. And it's posted before, that the non-universal amps have an input sensitivity of 100mA for rated power, while typical amps on the market are 1mA or thereabouts, and I am not sure what other preamps would offer such high-current output (the Spectral preamps output 1A). FWIW, my Berkeley certainly sounds thin going directly to the monos, and the preamp brings the missing dynamic brio to the dance.

EDIT: The other thing the preamps offer is oscillation protection circuitry (at the more expensive ones do).

Well all that doesn't exactly solve the issue, does it? The DMA-160 is not in production anymore, as far as I know (look at the 'Spectral Audio System' link), and I would want the DMA-260 quality. I know you need a pre-amp for your turntable, but others, like me, are digital-only listeners. So I personally don't care for a pre-amp with its extra expense -- they should make the power-amp so that it does NOT sound thin straight from the DAC; other amps (including mine) sound just fine that way.

And as for oscillation protection circuitry, that should be taken care of already by the mandatory Spectral/MIT interconnects.

Al

 

[ack]

Well all that doesn't exactly solve the issue, does it? The DMA-160 is not in production anymore, as far as I know (look at the 'Spectral Audio System' link), and I would want the DMA-260 quality. I know you need a pre-amp for your turntable, but others, like me, are digital-only listeners. So I personally don't care for a pre-amp with its extra expense -- they should make the power-amp so that it does NOT sound thin straight from the DAC; other amps (including mine) sound just fine that way.

And as for oscillation protection circuitry, that should be taken care of already by the mandatory Spectral/MIT interconnects.

Al

I am not sure I follow... you say it doesn't solve the problem, then you claim the Berkeley "sounds just fine" into your 260. So what exactly is the problem you are trying to solve? Are you looking to upgrade to the monos? If you are attempting to teach them how to design things, well, my sympathies. There is an old preamp/no-preamp thread here at WBF which is a very good read - some prefer preamps, others don't, and they explain why. FWIW, I've always had a preamp for the last 35 years, the TT analog arrived in 2009

 

[Al M.]

I am not sure I follow... you say it doesn't solve the problem, then you claim the Berkeley "sounds just fine" into your 260.

I had explained that for accidental reasons I hardly had listened in that mode, so I really don't know if there was some thinness or not.

So what exactly is the problem you are trying to solve?

The issue of retaining warranty under pre-amp less conditions, and the issue of not having to unnecessarily spend money. If they can custom-modify a DMA-180 for Reference Recordings then there is obviously no compelling technical reason why they could not offer a similar circuit as standard option for any interested buyers.

There is an old preamp/no-preamp thread here at WBF which is a very good read - some prefer preamps, others don't, and they explain why.

Do you have a link for that? Thanks.

 

[Al M.]

FWIW, I've always had a preamp for the last 35 years, the TT analog arrived in 2009

Well, digital volume controls have not been around for 35 years, things have changed, and there is no compelling technical reason (see above) why Spectral could not adapt to the times like everyone else. Having a purist approach doesn't necessarily mean ignoring your customers.

 

[ack]

I believe there is also an old thread here about voltage-driven vs current-driven amps (e.g. Krell CAST, et al) - also good read. I just don't think the problem you describe and especially the solution proposed is just as black and white.

PS: I don't think you will ever win on the warranty argument with them - see Russ's posts. They do things their way, take-it-or-leave-it; therefore, welcome to the aggravated crowd (don't get me started, I still don't know whether my transport will be fixed or not, and WHEN).