ack's system - end of round 1

[ack]

Hi chilest and welcome to WBF!

The mods are a little spread around this thread, but see http://www.whatsbestforum.com/showt...end-of-round-1&p=422685&viewfull=1#post422685 and http://www.whatsbestforum.com/showthread.php?2740-ack-s-system-end-of-round-1/page23 onwards.

The output filter modification in the analog section was meant to move the corner frequency from about 1MHz to about 193kHz, with the start of the rolloff at 176kHz (recognize that number?); the goal here was to reduce the amount of ultrasonic noise which the Spectrals would carry and amplify, and it was an eye-opener. The power supply modifications solidified the sound, and I verified its anticipated effectiveness with Berkeley before doing it. I have also found it effective to lift the chassis ground with a cheater plug. Elsewhere herein, you will find pictures of the output section which is now entirely shielded, and of mu-metal between the power supply and main board, to contain magnetic fields from the PS reaching the rest of the circuit. Sonically, the results are further validated now with the DMA-500 amps, and I get naturalness out of redbook digital as well.

 

[ack]

Further throughts on the DMA-500AR and 30SV's balanced-in module

A couple of folks asked me if I could provide a more details on the DMA-500s, and I was hoping to do so after I get my new panels; but here it goes anyway.

One of the things that got me thinking while having the 4000SV CD player in here was how clear its leading edge was; to make a long story short, it looks like I was originally right that the balanced-in module in the preamp - which I am using for the DAC - is indeed softening the leading edge, perhaps in an attempt to soften the typical harsh digital sound; it also attenuates amplitude by 9dB or so, as stated before. I ended up using that input for my DAC a while ago in order to avoid certain harshness; however, as it turns out, said harshness was apparently due to the DMA-400s, not the DAC, but the DAC was exposing it. So at the moment, the DAC is going into a typical RCA-in input again, and the gap between it and the 4000SV is now again narrower. It could also be that I was using an XLR-to-RCA adapter to use that balanced-in, but whatever it is, it is now proving not beneficial, at least not with this DAC, which is proving to be well-behaved driving the 500s.

Back to the 500s... I've been reading up on MegaFets, and sonically, this amplifier has exceptional control of my bass drivers, something I have never heard before in here; it feels like its output impedance is quite low. On the other end, the treble is extremely well defined, clear and controlled, all of which had me plugging the DAC into an RCA input again. I also find the midrange quite more resolving and clearer over the 400s, and at the same time, I am not hearing things in the upper bass in here that I hear through the Magico M3s with the same 4000SV, 30SV and 500s, so having the 4000SV in here didn't help, which means it's likely my bass drivers, less so the interconnects or speaker cables. Nonetheless, it's not a big deal, and I can live with that.

I also have to comment on their believable 3D presentation, also unlike anything I've heard in here before - and with digital. More on that in the future.

Back to digital, the amps are revealing actual noise with solo violin on Chandos, and I don't know if it's the DAC or the recording chain. But it is quite clear that, as the notes go higher in pitch, the noise clearly also elevates and becomes quite audible, rendered as a white hash. I am thinking it's the DAC or just the way digital is, and that's a semi-serious issue - and goes to show how ruthless these amps are. Truth be told, I first heard this type of noise from the Vivaldi 2.0 as well with Chesky and piano (rendered as a whoosh), so I am not sure what is going on (I did not play the Chandos on the Vivaldi or 4000SV back then). Perhaps this is the dithering noise typically applied to the input digital signal, which everyone claims is not audible?!? Well, this is quite audible and unnatural. I am beginning to wonder, will such a Spectral system sound really good with off the shelf digital? Or will it showcase its ugliness and require quite an investment...

With respect to analog, I have not even begun to critically evaluate it yet... I know, how can I possibly wait... been too busy with other things in the house.

 

[ack]

So I couldn't wait any longer and played the Sheffield Drum Record, D2D. Having played a couple of snare drum CD tracks before, I had to put this LP on the platter. The snappiness and impact of the drums had me blinking my eyes, in reaction to the attack of the sound; the leading edge is really extra-ordinary with these amps, and the dynamic headroom reaches a point that one may want to consider covering one's ears - a truly dramatic presentation. Equally important to me is that, part of the panel/woofer integration, is an amplifier's ability to control the speakers, something that I have said a number of times over the years. Said otherwise, an amplifier with a low damping factor may still make a panel sound great, but the slow, lumpy bass will render it disjointed. Thus, one needs an amplifier with exceptional control up and down the entire spectrum. These amps do that, and apparently quite well... and kickdrum, practically to die for. I am equally surprised how fast and dynamic this A90 is, and how well it tracks such challenging pieces - I am really impressed, but at the same time, my magnetic arm stabilization is also doing its magic.

 

[stevebythebay]

I’ve been using the 400’s w. 30SV into Wilson Alexia 2’s for quite some time. My MIT/Spectral cabling is rather old (MH770/MI350). I’d been considering upgrading to the 500s, but I believe that demands (literally) an upgrade to the newest Reference cables. Is that a mandatory requirement?

 

[ack]

Steve, I would ask the dealer, but I don't think it's a requirement. However, you are missing out on some great sounds from the newer cables. Even the original Oracle MA would be a major step up. Personally I would not get the 500s w/o simultaneously upgrading the cables.

 

[stevebythebay]

Steve, I would ask the dealer, but I don't think it's a requirement. However, you are missing out on some great sounds from the newer cables. Even the original Oracle MA would be a major step up. Personally I would not get the 500s w/o simultaneously upgrading the cables.

The dealer indicated it was a requirement to use the newer cables with the 500’s. I’d certainly like to entertain alternatives, if they won’t either violate Spectral’s warranty or provide better sonic performance. The cost of replacing both at once is daunting, to say the least.

 

[ack]

A quick call to the factory would clear any requirements out. The manual in the 400s and 500s does mention "phase-aligned' MIT cables, and I would consider the current generation as such, and not necessarily the ones you have; but that's a personal assessment. Nothing specific to model numbers, though.

 

[Mdp632]

The dealer indicated it was a requirement to use the newer cables with the 500’s. I’d certainly like to entertain alternatives, if they won’t either violate Spectral’s warranty or provide better sonic performance. The cost of replacing both at once is daunting, to say the least.

The new MIT 2C3D series of cables in the Heritage line is the new Spectral Ultralinear Series IV. The Spectral branded cables are sold via Spectral dealers who aren't also MIT dealers. They are just relabeled 2C3D cables as per my conversation with MIT. If you want a new and cost effective MIT solution this is probably your best bet.

Btw, any MIT network cable works with Spectral. It's just the Ultralinear line is certified by Spectral. As was the previous generations which to my knowledge were based on the Matrix HD ( Spectral Ultalinear Series 3)

I have MIT Evo One cables (Current generation) w/Spectral and they work fine but, hope to upgrade to all 2C3D when I can.

I've attached the catalog here and hope it helps.View attachment Spectral 2017 Retail prices.pdf

 

[stevebythebay]

The new MIT 2C3D series of cables in the Heritage line is the new Spectral Ultralinear Series IV. The Spectral branded cables are sold via Spectral dealers who aren't also MIT dealers. They are just relabeled 2C3D cables as per my conversation with MIT. If you want a new and cost effective MIT solution this is probably your best bet.

Btw, any MIT network cable works with Spectral. It's just the Ultralinear line is certified by Spectral. As was the previous generations which to my knowledge were based on the Matrix HD ( Spectral Ultalinear Series 3)

I have MIT One cables (Current generation) w/Spectral and they work fine but, hope to upgrade to all 2C3D when I can.

I've attached the catalog here and hope it helps.View attachment 41689

Yes. I'm not terribly enthusiastic about spending upwards of 25k for cables.

 

[Mdp632]

Yes. I'm not terribly enthusiastic about spending upwards of 25k for cables.

Steve,

Your dealer might still be able to order you the series 3 UL new from MIT. Earlier this year I purchased a new Spectral UL-230 5M cable for pre to amp. It's price was even well below what a new 2C3D Level 3 would have been.

 

[ack]

As a big proponent of system approach to engineering, I have to emphasize here that I am a HUGE fan of equipment that is voiced to work with certain cables. To that extent, although MIT makes or has made cables for Boulder (marked "B") and Constellation (marked "C"), I am aware of only two manufacturers that put an extreme emphasis - even a requirement - to use specific cables. Obviously, Spectral is one of them; the other one is FM Acoustics, and as discussed in the past, they require you to get their own speaker cables for their amps, do not want you to change the power cords, and I now see, they require you to even get their own phono interconnects.

From their web site https://www.fmacoustics.com/products/phono-linearizers/fm-223/

It is mandatory to use Precision Interface Technology® phono cables from the tonearm/turntable to the FM 223. The reason is that no other cable can guarantee the quality of true symmetrical balancing and - as important - the extremely high rejection of interference signals (CMRR). All other cables lower the interference rejection and thereby forfeit the huge effort that goes into achieving the ultimate rejection of noise, hum and interference. Only with P.I.T. phono cables can this interference rejection be achieved and at the tiny microvolt levels at which MC cartridges operate, this is very critical. To guarantee this it is mandatory to use Precision Interface Technology® phono cables from the tonearm/turntable to the FM 223. All other cables lower the interference rejection and thereby forfeit the huge effort that goes into achieving the singular true balanced signal preamplification of the FM 223. Only when P.I.T. phono cables are used can this interference rejection be achieved.

This is why a P.I.T. phono cable must be ordered with every FM 223.

 

[bonzo75]

I really like FM, and mullard88 has loads of experience with FM, including having their top preamps connected in series - yes he had two. His other two favorites are Spectral and Lamm, and he said the FM was the best of both. Just checking with other FM owners, some say the PIT is not a must. I don't have the experience to comment

 

[ack]

Yeah, I don't know about the "must" either, but their language is interesting. I also really like that their power cords are fixed and not detachable. FWIW, I also held FMA as the best in solid state, until the SV Spectral line came along. At this point, I am not sure, and another comparison would be required; I've always been captivated by FMA's claim of 200A (550A in the 1811 amps) peak output at the amplifier speaker terminals. And yes, we've read about Sam's preamps in series, at least the Spectral preamps... Interesting approach.

 

[Ron Resnick]

Congratulations, Tasos, on the new amplifiers! Enjoy them!

 

[ack]

Thanks Ron! I hope you get to hear a Spectral SV system one day - it certainly has life.

But the best news is hot off the press... after making the top high school in the state with a very high rank, plus making the school's symphonic orchestra, today, my 14 year old son was accepted at the New England Conservatory Prep School, and THAT is a big deal. He was able to do both with no effort and no pressure from us, and he practices very little. Although this is his big moment, I do take credit for exposing him to good music, at home and at live events. Just a couple of weeks ago, we went to the Blue Note to listen to the Duke Ellington Orchestra, and it was so rewarding to see him recognize some of the music I play here at home - imagine a kid high-fiving his dad for the great music at home. The kid is certainly a natural musician, but I know his passion is math and physics. But a musical mind is also a mathematical mind. He's building up a great resume and he'll do well.

The NEC is not only the oldest independent music school in the U.S., but one of the most distinguished in the world, right up there behind the Julliard, Oberlin and Curtis. I intend to donate significant amounts to its endowment.

 

[Al M.]

Thanks Ron! I hope you get to hear a Spectral SV system one day - it certainly has life.

But the best news is hot off the press... after making the top high school in the state with a very high rank, plus making the school's symphonic orchestra, today, my 14 year old son was accepted at the New England Conservatory Prep School, and THAT is a big deal. He was able to do both with no effort and no pressure from us, and he practices very little. Although this is his big moment, I do take credit for exposing him to good music, at home and at live events. Just a couple of weeks ago, we went to the Blue Note to listen to the Duke Ellington Orchestra, and it was so rewarding to see him recognize some of the music I play here at home - imagine a kid high-fiving his dad for the great music at home. The kid is certainly a natural musician, but I know his passion is math and physics. But a musical mind is also a mathematical mind. He's building up a great resume and he'll do well.

The NEC is not only the oldest independent music school in the U.S., but one of the most distinguished in the world, right up there behind the Julliard, Oberlin and Curtis. I intend to donate significant amounts to its endowment.

Wonderful news, congratulations to your son, and you, Tasos!

 

[LL21]

Thanks Ron! I hope you get to hear a Spectral SV system one day - it certainly has life.

But the best news is hot off the press... after making the top high school in the state with a very high rank, plus making the school's symphonic orchestra, today, my 14 year old son was accepted at the New England Conservatory Prep School, and THAT is a big deal. He was able to do both with no effort and no pressure from us, and he practices very little. Although this is his big moment, I do take credit for exposing him to good music, at home and at live events. Just a couple of weeks ago, we went to the Blue Note to listen to the Duke Ellington Orchestra, and it was so rewarding to see him recognize some of the music I play here at home - imagine a kid high-fiving his dad for the great music at home. The kid is certainly a natural musician, but I know his passion is math and physics. But a musical mind is also a mathematical mind. He's building up a great resume and he'll do well.

The NEC is not only the oldest independent music school in the U.S., but one of the most distinguished in the world, right up there behind the Julliard, Oberlin and Curtis. I intend to donate significant amounts to its endowment.

Congrats! That is big news and you are right to be very proud! Best wishes.

 

[Ron Resnick]

That is wonderful!

Congratulations to your son and the whole family!

 

[Mike Lavigne]

Thanks Ron! I hope you get to hear a Spectral SV system one day - it certainly has life.

But the best news is hot off the press... after making the top high school in the state with a very high rank, plus making the school's symphonic orchestra, today, my 14 year old son was accepted at the New England Conservatory Prep School, and THAT is a big deal. He was able to do both with no effort and no pressure from us, and he practices very little. Although this is his big moment, I do take credit for exposing him to good music, at home and at live events. Just a couple of weeks ago, we went to the Blue Note to listen to the Duke Ellington Orchestra, and it was so rewarding to see him recognize some of the music I play here at home - imagine a kid high-fiving his dad for the great music at home. The kid is certainly a natural musician, but I know his passion is math and physics. But a musical mind is also a mathematical mind. He's building up a great resume and he'll do well.

The NEC is not only the oldest independent music school in the U.S., but one of the most distinguished in the world, right up there behind the Julliard, Oberlin and Curtis. I intend to donate significant amounts to its endowment.

Tasos; congrats to you and your wife for your son's big moment (and many more to come from the sounds of it). these things are never an accident. and there is nothing in this world that compares to recognition for your children....it's as good as it gets. enjoy it.

 

[PeterA]

Congratulations Tasos. Good schools are extremely selective these days. You should be proud. I remember meeting your son a couple of times. He's a nice young man. I think he enjoys your system more than he seemed to enjoy mine a couple of Summers ago. And you didn't even have the super Spectral gear then.