Spectral DMC-30 SV

[geppo]

Forgot to mention, and for completeness, there might be some differences between semiconductors that are simply not evident because markings of small parts are not readable.

I'd be curious to know what the marking is on the new "custom" dual J-FET...

 

[ack]

Interesting to note that the latest and greatest SV release has a new PCB artwork. This can be seen on just a couple of tracks running from resistors to the new TO71 dual J-FET that replaced the old NPD5566. Now that I've seen the new balanced board it makes sense to me. Spectral wanted to use the same J-FET for both a SMT and a THT board and installing a THT part in an SMD board is easier than the opposite. So, if only one part needs to be used it has to be THT.

Glad to hear this; I had no doubts that, however simplistic the board may look, it would be optimized for the new J-FETs. And who knows, there may be other supporting changes in the motherboard.

Like I said, it may be custom but it surely isn't a breakthrough new kind of dual J-FET. Discrete J-FETs are legacy technology like tubes. Minor refinements may be possible but, in most cases, small companies are striving to replicate, not exceed, the quality of old Toshiba and Siliconix parts.

Responding to the highlighted parts, could it be that they found older J-FETs that, if modified according to someone's specifications, they would yield a superior part?

One more question: what if the metal casing was chosen to shield against noise (to use a generic term) and/or to aid in heat dissipation? The manual says the SV can swing 100V @2A peaks at the output jacks (I assume the balanced out, or 1A from the SE, sez me). Does that tell you anything?

I hope I correctly explained why, in my experience, I tend to be skeptical when I hear of breakthrough new semis specifically designed for audio, packaged in THT packages.

There is certainly a wide range of interpretations of the word "custom": from modified originals, to totally brand-new.

Soon I will get to the preamp's sound, but for now, I have a couple of things to share: I swapped my HiFi Tuning Supreme fuses out for the stock ones in the 400RS amplifiers, and the bass lost weight; so back in the Supremes went. I then replaced the SV's fuse with a Supreme, and the bass became muddier, so back in the stock went. Fascinating, if not weird...

 

[geppo]

Responding to the highlighted parts, could it be that they found older J-FETs that, if modified according to someone's specifications, they would yield a superior part?

Yes, I think they found older parts - but newer than the original NPD5566 - re-packaged in a metal can that are a better alternative in their circuit. My only complaint is about how long it took to replace an obsolete part.

One more question: what if the metal casing was chosen to shield against noise (to use a generic term) and/or to aid in heat dissipation?

Hermetically sealed - metal cans and side brazed ceramic - parts used to be much better than equivalent plastic parts, originally. Then the semiconductor industry moved away from military/aerospace to join the computing/consumer bandwagon. Nowadays volumes is what makes quality and the difference between metal and plastic is marginal if not even reversed. Of course there are applications still requiring hermetically sealed parts but audio is not one of which. Nevertheless, the modern National Semiconductor line of OpAmps made for audio and available in both plastic and metal packages is said - by one of the designer - to perform better when packaged in metal cans. Fascinating, if not weird - to paraphrase your comment

 

[ack]

metal packages is said - by one of the designer - to perform better when packaged in metal cans. Fascinating, if not weird - to paraphrase your comment

One designer??? Add another one, perhaps??? Question: what packaging would one rather use in harsh environments, like aero-space? And what sort of packaging would one prefer for devices operating in such wide [for audio] bandwidths, into the MHz, if one were to design such a "custom" device?

If nothing else, the execution in the 30SV appears to be a stroke of genius.

PS: I'll try to get close-ups of the J-FET markings; time for a macro lens

 

[geppo]

Question: what packaging would one rather use in harsh environments, like aero-space? And what sort of packaging would one prefer for devices operating in such wide [for audio] bandwidths, into the MHz, if one were to design such a "custom" device?

If harsh environment and wide bandwidths are both a requirement, modern ceramic packages are available for the task, see this Semelab webpage for some examples. Worth to note that the TO71 selected by Spectral is listed as a traditional package here (TO71 has the same overall size of a TO18 and the number of pins of a TO77), like the DIP8 it replaces in the Spectral application I would say.

 

[ack]

I never had to do this kind of sleuthing before! A quick google search turned up nothing, only a license plate! I thought that was cute! I don't think there is any doubt this is a proprietary device, and once again, they seem to have found a way to advance the state of the art by thinking outside of the box.

 

[geppo]

ack,

Thank you for the pictures and the P/N for the custom dual J-FET. And, yes, it is a custom part.

I don't think there is any doubt this is a proprietary device

Well, maybe not.

Anybody, willing to shell out some 25€ can buy the same chip, in the modern SMD package I've been advocating for a while, from a catalogue distributor like Mouser, just follow the link.

a way to advance the state of the art by thinking outside of the box

BTW, John Curl is a well known and well respected audio designer, a JFET expert. Scott Wurcer is less known among audiophiles but is nevertheless one of the greatest experts in the semiconductor industry. He designed ICs for Analog Devices for decades - the AD797 among many others and some ADSL drivers which are probably connecting more than 50% of internet users worldwide.

I still think the balanced board is the real innovation in the SV version of the Spectral preamp.

 

[ack]

I can't decipher the conference link or Curl's comments (BTW, we all know who he is), but if you agree it's a custom part (but not necessarily proprietary), then I don't have anything else to add - "custom" is what they claim. Perhaps I stretched it too much by saying "proprietary". However, it seems to me we have come a long way from your original claim that "I'm quite sure this is a re-badged LSK389C from Linear Integrated System" in post #35. I feel there is conclusion here, as probably very few people are able to follow.

At this point, I think it's time to start talking about the sound... and given the Thanksgiving holiday, I am going to take a little break while I continue to evaluate the unit, but I can safely "warn" you to prepare for a small explosion of exuberance

 

[geppo]

ack,

Enjoy the Thanksgiving holiday with your loved ones and a lot of great music from a great preamp and system.

After all, that is what really matters.

 

[ack]

I have now permanently installed the original fuses in the amps as well; after careful listening, it's quite clear the HiFi Tuning Supreme are slower, affecting the leading edge of the bass, giving a false sense of fuller bass. At the end of the day, the original fuses offer a jump factor, control and tightness that the HiFi Tuning simply can't - quite evident with the Sheffield Drum Record and the Reference Recordings RR-11 Berlioz Symphonie Fantastique LPs. The bursts of explosion of the orchestra, timpani and bass drums and overall authority are unmistakable; during the last few days' worth of auditioning, I can't recall how many times I've been thrown back on my seat by the shear macro dynamics and instantaneous wave launch. The Fantastique's Finale is a monster of a recording, and it comes across as such, with heavy repeated drum whacks and a final explosion of sound that's riveting.

At the beginning of the thread, I mentioned back in May that the first thing that grabs you with the 30SV is the overall vividness; after having played a number of symphonic pieces, this vividness is easily evident with everything I have played, and even more so than I had originally thought. Let me revisit and expand on what what I said back then:

• increased vividness all around, rendering timbres even more realistically; attack with timpani and drums is really spectacular, winds and strings have intoxicating micro-dynamics. Notes linger longer; lower noise renders even more micro detail. The piano's hammer strikes are rendered so well that I could say piano is finally very realistic. Compared to the 30SS S2, it's like looking at a sharper photograph, though both could be pleasing to the ear (eye). I think this vividness is what strikes you at first, and quite quickly
  
• it's interesting that the minor euphonic sound in sections of the midrange of the 360s/30SS S2 went mostly away with the 400s and the newer (my late serial #) SS S2, and even more so now with the SV driving the 400s
• dynamic headroom is also improved, especially evident with winds
• there is more mid-bass body, and very controlled and extended deep bass
• effortless rendition with the most complex of passages, portraying each instrument quite distinctly from all others

Timbre and articulation: That's the title on my system thread, and I chose it because that has been my goal for decades: to build a system that offers realistic instrumental sounds, clearly and distinctly from any other, with proper dynamic expression, from any recording I'd wish to play. It should also be no secret that my avatar - the A90 - was chosen out of admiration for this incredibly linear device, which, as a source, is where it all begins. I feel the 35-year quest for Timbre And Articulation has been achieved to such a level that the sense of illusion is sufficiently high as to fool one into forgetting they are listening to a stereo system. This past Thanksgiving I was watching for the unsuspecting guests' reactions to music I played, and it was unanimous: foot tapping, dancing (to jazz), to comments like "have you changed anything, this is sensational"?

To get to true timbre, a system must also conquer micro-dynamics; the improvement in this area is also quite evident. Right before the holiday, the Janaki String Trio's Debut LP arrived - a recording that Myles Astor used in tape format to showcase the Audia Flight amplifier he was reviewing - and the sense of string micro-dynamics is truly captivating.

It has been said many times that accurately rendering a piano is one of the most difficult challenges for a system. I recently bought RR's Nojima Plays Ravel LP, and I feel the reproduction is extra-ordinarily realistic. Another acid test is PeterA's favorite piano LP, Beethoven's Appasionata, a Direct To Disc RCA with Ikuyo Kamiyo. These two recordings are rendered with hair-raising truth of timbre, micro and macro dynamics.

The next type of acid test is full-blown symphonic works. The Fantastique is one, and my favorite Mahler 2nd is another (out of hundreds, of course). About fifteen years ago, my wife and I attended the BSO performance of the 2nd led by Ozawa (all others, it's been just me); at the end of it, she was crying at the sheer impact of that performance. On the way back home, she said: "Sorry baby, your system sounds nothing like this", and she was right. Two days ago, I played the Philips LP (digital recording) again, and it was interesting watching her glued to the sound; at the end, she didn't shed a tear, but the emotional involvement was still there. While I have never heard a recording of this symphony and system do justice to the chorus and the extreme dynamics overshadowing the entire orchestra at Symphony Hall, the overall orchestral rendition in this system is now subjectively extra-ordinary; and with the advent of the 30SV, there is no more grain in the voices, a trait I have noticed on Telarc's Carmina Burana and other mass-choral pieces (like Beethoven's 9th) as well.

Resolution is yet another area of improvement. This is really a generic term that can span anything from hearing new details for the first time, to improved micro-dynamics (and thus timbre), to greater sense of depth, etc... it's all there.

To repeat what I also said in May, all of this is a tribute to the sources as well. In particular, my appreciation and respect for the A90 is at an all-time high, as is for this heavily modified XP-25 phono (a significant improvement over stock). And of course, one cannot ignore these remarkable 400RS amplifiers, which were being held back up until now... and God knows what more there is for us to discover when the Spectral phono is finally a reality.

As it stands right now, I keep telling myself: don't change a freaking thing; just enjoy your music. The positive impact that the 30SV has made is not one of a thing here, or a thing there. As the musical material gets more complex, one realizes it's a universal giant step forward, plain and simple... BTW, my phono is plugged into the balanced input.

As I write all this, I realize I can't stop thinking about the music I've heard the last few days... Rachmaninoff's Symphonic Dances; Stravinsky's Firebird, Song of the Nightingale, Rite of Spring; Bruch's Scottish Fantasy and the power of the violin in there... Oh, and that sound of the oboe - man, I hate that instrument with passion, and even more so now

I need to get back to my Mahler right now, and will follow up in a week's time or so. But so far, I should repeat, this preamp and the 400RS amps are a stroke of genius.

I hope everyone's Thanksgiving was as glorious as ours!

 

[stevebythebay]

OK. You've really got me salivating. I've been a happy camper over the past 3 years with my DMA-260 stero and 30SS-S2 pre. Still awaiting a pair of DMA-400's along with the 30SV. Hope to have everything in place before year's end. By the way, have you found an optimal placement (especially with respect to distance isolation) for the pre-amp and amps? I know my current setup is to get these as far apart as possible, so as to prevent any type of interference.

My current system (sorry no pics): Aurender N10 / Synergistic Research active cabling:USB (Galileo LE)/XLR/Interconnects - HFT&FEQ Room Treatment - UEF Tuning Circuits - PowerCell 10 - Transporter Ultra - Tranquility Base - Grounding Block and Hi-Def cabling - Black Box / Berkeley Audio Design Alpha USB and Reference DAC / Spectral DMC-30SS Series 2 / Spectral DMA-260 / Wilson Audio Alexia speakers/HRS SXR stands with M3X Isolation Bases

 

[ack]

My amps are a well 3ft apart, and the preamp about the same from either. Would love to hear your listening impressions.

 

[stevebythebay]

Will let you know once I've got the new Spectral gear in place and "burned in".

 

[ack]

There are a couple more thoughts I'd like to share, given the opportunity... One of the most obvious things I think you will notice is how much more treble energy there is with these amps and preamp; then, how much better control of the music they impart; and finally, how considerably lower the noise floor is. I'd say, all of them should be obvious in your system.

Since my last report, I have been listening to digital as well, comparing with analog. I should have expected this, but the improvements with analog are much more pronounced than redbook digital (though I need to point out both benefited from the preamp upgrade); and I should have expected it because I've always considered good analog a hi-res medium, which RBCD isn't. Specific to the Berkeley DACs, it was interesting to realize how fast and articulate they already are, but at the same time, I also think the ugliness of digital with some recordings is now even more evident; I feel compelled to try again hi-res PCM with my Alpha. So I am really interested in your own findings with your all-digital set-up.

 

[stevebythebay]

Will let you know. By the way, are you using the Berkeley Alpha USB with your DAC? Are you using something that avoids USB output to the DAC? What modification was done to the DAC? Could not really tell from the photo of your system.

 

[ack]

No USB spoken here; only AES/EBU from the transport (USB is really why I never went hi-res PCM; I was thinking of the Baetis reference to try). The mods are mostly wrt shielding of the output section, with some minor in the power supply.

 

[stevebythebay]

Before getting the Aurender N10 I'd had an opportunity to bring in a Baetis Reference from a local dealer. Tested both (1) AES/EBU straight into my Berkeley Ref. as well as (2) the USB input via the Berkeley Alpha USB. Was using a late 2014 Mac Mini as the source at that time (in February of this year). Have to say that my limited experience with the Baetis was that the USB sounded somewhat better.

And that was even before I'd replaced the power cord on the Alpha USB with a better one. And this latter experiment (using a Synergistic Research top of the line CTS power cord) made a very significant improvement in the overall sound quality of the system. I can only guess that the Alpha USB is quite sensitive to the cleanest of power.

You never know what you'll uncover in pursuing this hobby.

 

[jfkbike]

But so far, I should repeat, this preamp and the 400RS amps are a stroke of genius.

Ack, very articulate review. I also have this same setup and agree with your conclusions. Although I was guilty of changing a few things all at once and not going back and forth to A/B them. The first thing I noticed was the greater depth of the sound stage and the blacker background from which it emanated followed closely by much more detail and as you said, hearing new details for the first time.

As an interesting aside I took my 30SS and put it in place of DMC-20 S2 that I was using along with a DMA 260 in a small second home system and that was fun to hear that improvement. Spectral has come a long way. BTW the DMC-20 S2 is for sale now on Audiogon.

Have you tried the MIT articulation consoles yet? They are quite something.

 

[ack]

I was hoping to hear from you, jfkbike! On the Articulation Consoles, yes, I have heard them, and have a thread on this forum. As you say, they are quite something. I believe I heard them last with the 30SV/400RS this past August, driving the Q5, and the sense of vividness was just out of this world.

Thinking about the Spectral sound over the last 20-25 years, yes they absolutely have come a long way, like just about everyone else. Not only do I hear things for the first time, it's the stuff that was there before but not as distinct that grabbed me the most. For example, in the RR Capriccio Italien that I was playing last weekend, all of a sudden there are bells tolled, toward the end. I had never noticed this before, yet I am sure they were there, though subdued.

Just this morning, I moved on to the next acid test - full orchestra with organ, like my much-beloved Guilmant's Symphony No.1 (first movement) on this CD https://www.youtube.com/watch?v=JYondZiqS6Q especially the finale at 7:45 - I've been trying to reproduce this for 15 years, and today the sound was one of those "wow" moments. Then I compared to RR's version with Felix Hell, just organ, RR-101, and the rendition was just effortless, though this is one of those cases I'd say, geez, I hope I had the Q7s for realistic scale.

BTW, the thought of getting another pair of 400RS for bi-amping has crossed my mind ... talking about audiophile excessiveness... but these are the kinds of electronics that make ME stand up and dance.

 

[stevebythebay]

When I last visited this post I was awaiting my gear. A couple of weeks ago I finally received word that my 400RS monoblocks were at my dealer, awaiting pickup. So, I eagerly arrived the next day with my 260 stereo amp for the trade-up. Since I didn't have the capacity to put these new units in the car, I waited for my dealer's van and drivers. A few hours passed and suddenly out of the blue they told me that the 30SV had just arrived. Sudden Halleluya chorus! Set everything up by day's end and proceeded to start on listening. Since I had no way to A-B things, given I'd swapped out both the 30SS S2 and 260 stereo amp, I can only surmise that what I was now hearing is a result of the combination.

I can only echo what you have already stated. My Wilson Alexia's are now happier to effortlessly deliver the sonic goods. The speed and articulation and just plain more realistic presentation are amazing. The increased width and depth of soundstage led to bringing the speakers not only a bit closer to each other, but caused me to sit about a half foot closer as well. The clarity of all voices, instruments, and layering of sounds as well as sheer dynamics has elevated my system substantially. The noise floor is a very clear measure below where it's been to date. Seems that there's less of a "sweet spot" in pre-amps output level. And it seems that the attenuator or whatever is used to control volume is just cleaner. And there is far more sonic information coming through as a result of all this, warts and all. That is as it should be.

Although I don't think I'll stop pursuing anything that will make the system ever more realistic, these two new components open the door to more investigation in source, cabling, isolation and many other areas. As things stand I'm one happy camper.