Robert Harley about the Alpha DAC

SlickenSmooth -- Thu, 01/28/2010 - 08:44

I'd like to have your advice about it as a preamp for my Spectral DMA-250.
How would you rate it against a good Spectral preamp? My dealer likes the Alpha Dac a LOT, but he says he'll always prefer a Spectral preamp to drive a Spectral poweramp. He says it's because of 1) synergy and 2) the Alpha Dac is a good preamp but definitely not as good as a Spectral 30SL G2/ SHAA2 or a 30SS.
I ask this because I have to choose between 2 setups to live with for a while:
1) PC-Lynx AES16 > Berkeley Alpha Dac > Spectral DMA-250 > Magnum MA Cables
2) Spectral 30SL G2/ SHAA2 > Spectral DMA-250 > DCS Puccini CD player or Audio Research Reference CD 8 > Magnum MA cables
What's your advice on this? I cannot audition the Alpha DAC as I need to import it.

ScottB (not verified) -- Thu, 01/28/2010 - 10:05

 RH has said, in other contexts, that he preferred the sound of the AlphaDAC directly driving Spectral DMA-360 amps, over the sound with the Spectral preamp between the DAC and amps. He also characterized the AlphaDAC as the best digital sound he'd heard (prior to his auditioning of the Meridian 808.2).
I've used the AlphaDAC to drive Spectral DMA-360 V2 amps directly, with MIT Magnum MA cabling, for 9 months now, first with Magico V3, now with Magico M5. The sound is spectacular, as you might imagine, but I haven't compared it with a different digital source and Spectral preamp.

Sam -- Thu, 01/28/2010 - 15:48

Scott, I know that Robert and you are Driving the DMA 360 directly with Berkeley. Is yours and Roberts amps the universal model? Because Goodwins website says that the non universal one must be used with a spectral preamp. Can the spectrals be used with other preamps safely if one already has a preamp turntable setup? and for digital driving them directly By Berkeley? What source are u using with Berkeley? Was it the blue smoke? And how big of a jump or difference is v3 compared to M3? Robert said the V3 is equal to many $100k speakers. Thanks.

SlickenSmooth -- Thu, 01/28/2010 - 18:46

Thanks for the insights ScottB.
I'm planning on getting the Magico V3 sometime soon! Auditioned it the other day and what an amazing speaker!
It's a really hard decision. I'm really interested if someone has A/B tested the situation I stated above. I really want to believe in my dealer as he has over 30 years of experience in high-end audio (and his Spectral system with V3 sounds amazing), but on the internet I've only read great things about the alpha DAC driving Spectral amps. A thing that puts me off a bit about the alpha dac is that I need to use a computer as a source.. As I don't have much experience on computeraudio.. But somehow I DO feel it will be standard of the future and that's why I'd like to have an answer so that I won't regret my decision. Somehow I feel though that a system that consists of 30-SS/ 360-S2/ SDR-4000 PRO/ MIT CABLING is superior to a setup with the Berkeley DAC in it.

Silence is Music

ScottB (not verified) -- Thu, 01/28/2010 - 19:24

You're correct about Spectral's preamp requirements, and I should have said something about this above. Spectral very explicitly states that their non-universal amplifiers are not warranted for use with anything other than Spectral preamps and MIT or Spectral/MIT cables. This is apparently because the extremely high bandwidth of Spectral amps creates the potential for destructive ultrasonic instability with some preamp output circuits. Goodwins, my Spectral dealer, was very explicit with me about this requirement when they sold me the DMA-360s. However, the DMA-360 S2 was not available at the time (probably still isn't) in a universal version, and I elected to go ahead and buy them anyway, and use the AlphaDAC as preamp, knowing that Spectral has the right to deny warranty and ask for full payment on repairs if the amps are damaged.
I would not have taken this risk with any preamp other than the AlphaDAC. I felt reasonably confident there wouldn't be problems, because the AlphaDAC is designed with a very robust, stable output stage for use in studio environments, the Berkeley folks actually use the DMA-360 as their reference amp, and quite a few other people have apparently used this same combination without incident (including RH, although he may not have been aware of Spectral's requirements). But it is a risk, and I don't want to be in the position of recommending things that could cause people problems.
The M5 vs. V3 is an interesting question. The V3s are exceptional speakers, in every way that the reviews say they are - transparent, lifelike midrange, very clean treble, great resolution, big soundstage and excellent imaging within the stage, taut, controlled, and fairly deep bass response. The M5s, as you would expect, go deeper and are more dynamic in the bass. What I didn't expect was the improvement in midrange on up, as well. The M5s are so resolving, transparent, and coherent from the midrange on up. My local dealer says they're the first dynamic speaker that has impressed their Quad customers, and I can see (or rather, hear) why. By contrast, the V3s are slightly more veiled, not quite as seamless from midrange to treble, and ever so slightly rough in the treble - and the V3s were already the best dynamic speakers I'd heard in these areas before.
I don't want to exaggerate the differences - these are not "huge" differences, certainly not $60K worth of difference in an absolute objective sense. I'd still be a happy V3 owner if I hadn't been presented with an opportunity I couldn't pass up. At the same time, the M5s have a way of sounding very consistently right and real that seems to go beyond the sum of their audiophile virtues. Anecdotally, this is the first speaker I've had that has prompted several non-audiophile acquaintances, men and women, to remark unprompted on the realism of the sound. It serves the music like no other speaker I've heard, and I don't expect to replace it for a long time - and not just because I can't justify that kind of expenditure again any time soon.

ScottB (not verified) -- Thu, 01/28/2010 - 20:20

Your last post ended up between Sam's and mine, a couple of more comments. First, as I said above, the V3s are terrific, and you'll love them. Also, I think you'll be very happy with any of the combinations you listed from a sound perspective. I went with the AlphaDAC because I'd already made the move from discs to music server, which all by itself made my music collection much more "discoverable" and therefore enjoyable.
Finally, please read my comments above on Spectral's policy of using only Spectral preamps with non-universal amps, and make an informed decision for yourself.

Robert Harley -- Sun, 01/31/2010 - 14:46

I have not had a problem with the Alpha DAC driving the DMA-360s, and in fact prefer the sound of that system to one in which the Alpha DAC goes through the Spectral DMC-30SS (or any other top-tier preamplifier I've tried).

Ana collard (not verified) -- Sun, 01/31/2010 - 16:00

What about the alpha dac or the 30-SS driving the 360's? Which setting do you find better and why?

Robert Harley -- Sun, 01/31/2010 - 20:16

I find that the best sound is achieved with the Alpha DAC driving the DMA-360 directly rather than through the DMC-30SS.

Sam -- Mon, 02/01/2010 - 02:01

Robert, there are 2 models. One is universal and other is not. Per spectral the non universal must be used with spectral pre amp. Which model are you talking about? Would it destroy the warranty if non universal is used with berkely o different model preamp other than spectral? Is the universal model lesser in quality relative to non universal dma360?

Robert Harley -- Tue, 02/02/2010 - 16:53

I don't know for certain, but my understanding is that the universal models made for recording studios simply have reduced bandwidth relative to the standard (home) models. This is why the universal models don't require the band-limiting effect of MIT cables.

ral -- Sun, 02/07/2010 - 21:29

A question for Robert Harley.   You have mentioned in TAS that one of your reference systems consists of the Berkeley DAC, Pass XP20 preamp, and Pass XA100.5 amps.  What sonic differences do you hear when driving those amps directly from the DAC?  Do you ever feel that the digital attenuation required of the DAC (in the absence of the preamp) compromises the sound in any audible way?

Robert Harley -- Mon, 02/08/2010 - 23:44

I operate the Berkeley DAC with no more than 10dB of attenuation in my system for most serious listening, and have not heard any artifacts attributable to the digital volume control.
The improvement I hear driving a power amplifier directly with the Berkeley rather than going through a preamplifier includes greater resolution of the lowest level details, more liquid timbres, greater transparency, and a more spacious soundstage.

SteveS (not verified) -- Wed, 03/24/2010 - 01:51

Hi Robert, you are just the man I need to talk to. I just purchased a new Spectron Musician lll Mk2 amp to go with my Gallo Ref 3 speakers and I am considering a Simaudio Supernova CD player and Pass Labs xp-10 pre. Do you think the Alpha Dac direct to my amp would equal or better the above CD player and pre.

I have yet to buy my pre and CD player b/c I am strongly considering the Alpha Dac direct to the amp. Could you give me a brief overview of your system. Do you use a PC or the computer specifically designed or set up for music serving. Do you use an external NAS and do you have back-up. Furthermore what software do you use and what do you use as a controller are you able to integrate a remote of some kind. Have you found your setup to be reliable?

SteveS -- Wed, 03/24/2010 - 02:28

Hi Robert, I just purchased a new Spectron Musician lll Mk2 amp to go with a pair of Gallo Ref 3 speakers and I am considering a Simaudio Supernova CD player and Pass Labs xp-10 pre. Do you think the Alpha Dac direct to my amp would equal or better the above CD player and pre combo.

I have yet to buy my pre and CD player b/c I am strongly considering the Alpha Dac direct to the amp. Could you please give me a brief overview of your system. Do you use a PC or the computer specifically designed or set up for music serving. What software do you use and what do you use as a controller. Are you able to integrate a remote of some kind and through the remote you able to select songs and control volume. Do you use an external NAS and do you have back-up. Have you found your setup to be reliable? Could you please include what brands you are using for any of the above.

Can you please also comment if you would consider the Alpha Dac to be more forward sounding or would you consider it to be relaxed. Could you also include what speakers and amp you are using.


Robert Harley -- Wed, 03/24/2010 - 15:13

Hi SteveS. If you have just a single digital source, going straight into the amplifiers with the DAC is a great idea. This connection method is, however, impractical if you have more than one source.

You can read the complete details of my music server in Issue 189, and the of the Alpha DAC and associated components used to evaluate the Alpha DAC also in Issue 189.

Geophysicist -- Tue, 03/30/2010 - 16:53

We've had this discussion before, but it's worth repeating in this context. I've driven my Atma-Sphere amp directly from the Alpha (bypassing the Messenger preamp) and auditioned at length, and would agree with 2 or 4 of Robert's statements:

1) greater resolution of the lowest level details - definitely, although it's subtle
2) more liquid timbres - contrary to my experience, although again it is not a major issue
3) greater transparency - very, very subtle, but yes
4) more spacious soundstage - absolutely not

Obviously #4 is the real deal-killer for me, as soundstage and imaging is near the top of my list of priorities. I find that the 'direct drive' route collapses the depth dimension significantly. If it's not a priority for you, then the benefits are there.

Sam -- Tue, 03/30/2010 - 17:19

Could your findings be specific to your setup involving Atma-Sphere amps and Messenger preamp rather than what Robert found? Im sure what you are saying must be true since you tested it out on your system. Robert Harley on the other hand has tested the Berkeley with several state of the art amplifiers with and without state of the art preamplifier and found that without a preamp in those setups that he tested the Berkeley sounded better. I don't doubt his findings either.

Geophysicist -- Wed, 03/31/2010 - 07:15


I don't question Robert's findings in any way. I'm simply saying that, in my system, taking the preamp out of the equation significantly flattened the soundstage. Even my distinctly non-audiophile wife noticed it - "why are the drums (i.e. tympani) so much closer?". I fully understand the potential benefits of getting rid of an active line stage, but can't live with what I consider a major downside. In any event, I'm a vinyl guy and need the preamp, although the combination of the Music Vault Diamond and the Berkeley have shifted my source habits considerably. Previously, it was typically 10% digits, 90% vinyl. Now it's closer to 50/50.

SlickenSmooth -- Tue, 03/30/2010 - 18:48

Finally have a CD player on hand which can be used as a preamp. The Wadia 381i. Although I haven't tested it thorougly yet my first impressions are almost the same as Geophysicist.
Wadia 381i (source and preamp Wadia 381i) vs Spectral 30-SL (source: Wadia 381i)
poweramp used: Spectral DMA-250
Results so far:
Transparency: Wadia, subtle
Resolution: Wadia, subtle
Timbres: Spectral
True to source: Wadia, less colouration, wether it sounds better depends on preference. i.e. female vocals lose a shiny glowiness with the Wadia as a pre, but do sound more like their real voice.
Soundstage: Spectral, Spectral, Spectral. By a wide margin.
As you can see it's pretty evenly matched. I will post more of my findings later on.

Silence is Music

Robert Harley -- Tue, 03/30/2010 - 22:40

Thanks for sharing your observations. Let us know what you decide.

Sam -- Tue, 03/30/2010 - 23:48

Robert, When you were driving the Spectral DMA 360 series II mono amps directly with BAD alpha DAC you reported no problems.  Technologically speaking, was that just a stroke of luck? Is it possible that over a longer period of use like this some damage could have occured to the Amplifier, speaker or the DAC?  Spectral insists that their amp be driven with a spectral preamp, whats the technichal basis of that? Firstly: what would get damaged? the Speakers? Power amp? or the Berkeley? Secondly: What kind of damage are we talking about? My understanding was that The Berkeley guys are very well familiar with the spectral amps and have created the DAC to work well with it directly.  Where as other preamps may have issues with it.  I know that many people including you have driven them safely and spectral has its own view.  At a technical level what are your thoughts? A direct connection....would it be safe or not? It would be nice to know considering how costly all this setup is....we are not talking about pocket change here.   

SlickenSmooth -- Thu, 04/01/2010 - 17:14

My impressions have stayed more or less the same after some intensive listening.
Transparency: Wadia, subtle.
Resolution: Wadia, subtle.
Timbres: Spectral. Seperation is slightly better with the Wadia but the Spectral sounds more coherent. Notes seem to go on a bit longer which makes it more 'liquid' or 'flowing' if you will. This is very  noticeable with vocals.
True to source: Wadia, less colouration. The 30SL is a bit darkish by nature. The 30SS sounds fresher and would probably take this away. If you would take the Soulution 720 preamp which I've heard this week it will be colorless, with all the benefits of a preamp.
Soundstage: Spectral, Spectral, Spectral. By a wide margin. With a live recording, Spectral makes it sound like you're in a concert hall. The Wadia more like in a studio. The Spectral teleports you better to the venue of the music imo.
I really wanted to like preampless better. As I would save some nice $$$. But I really do prefer the sound WITH the 30SL, which is long from being the best preamp these days. Soundstage and coherency is really important for me. I enjoyed the extra bit of resolution and transparency without the preamp but after a while found it sounding analytical. With preamp it sounded more like music. This is just my system and my experience, try and see what works best for you! Just my 2 cents.

Silence is Music

Marcel -- Wed, 04/14/2010 - 14:34

Thanks for your report.
I also once briefly tried to connect the Spectral SDR 4000 directly into the Spectral power amps, and got a similar result to what you describe so clearly. Overall, I prefered the setup with a (very good) pre-amp in the system.

Jlaz (not verified) -- Fri, 04/16/2010 - 22:47

I am deciding between the Naim Dac and the Berkeley audio alpha dac.  My current system is mostly naim equipment, the naim 282 with a 250 power amp.  I am using it with cremona auditor speakers.  I have heard both but not on the naim set up (only the naim dac as part of the chain).   I really liked the berkeley dac, but heard it on a pass labs class a amp.  What are the differences between the two designs?  

Robert Harley -- Sun, 04/18/2010 - 10:16

I'm not familiar with the Naim. Is it possible for you to audition both the Berkeley and the Naim in your own system before you buy? That''s the foolproof method of getting the best-sounding DAC for your tastes and system.

arjansmeulders -- Sun, 10/30/2011 - 14:11

Dear Mr. Harley,
I'm puzzled. About 2 years ago I set on a quest to find a high end system that would satisfy my needs. What I didn't want is go on and on until I die with searching for the best but rather choose a few brands and then once every 3 or 4 year buy their latetst model or upgrade. I'm almost there. I have a Linn Akurate DS (logical upgrade Klimax DS/0 and then DS/1), Spectral 30SS (upgrade is series 2), Spectral 360 version 1 (upgrade 260), Watt Pupp 7 (Sasha or possibly Magico) and MIT MA. So far so good. But now I read in this post that you prefer the sound of the Berkeley Alpha DAC straight into the 360 rather then using the preamp. How is this possible? Are the output stages of the Alpha (worth 50 bucks?) better then a preamplifier worth 10.000+ which is almost for 30 years in development? Does this mean that in the near future no one will need a world class preamp?  I once compared the 33SS with the Music First Audio reference passive preamp (also 10.000). This is essential a volume control with no active parts. Good but no match for the spectral. It's off course very transparant but what's lacking is the salt in the soup. That's what preamps are for I believe. Thing is, i can't listen to the berkeley as it is not available in the netherlands due CE regulation. Would love to hear it though because I would like to audition an alternative for the Linn line of products. (If you ever have the change to review the Klimax DS/1 and compare it to the Alpha I would be most gratefull.)
But back to bewilderment....The berkeley alpha sounds better without the 30SS? I just can't believe it....
Thanks you very much for your attention. I did by some stuff in the past partly based on your recommendations and to great pleasure I may add.
Kind Regards

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