Questyle CMA800 Current Mode amp
Dec 19, 2013 at 6:29 PM Post #151 of 757
Nice list, and prolly fairly exhaustive to boot, but if one were to lay in such a DAC/amp mostly just to support the CMA800R dual mono configuration, which one(s) would you perceive as the biggest bang for the buck, or at least without introducing significant deterioration of SQ, such as signal distortion or diminished staging, which would kind of defeat the purpose of the dual monoblocks? Your Yulong DA8, such as yzap referred to?  And you'd probably need to multi-task such a component in your audio set-up, anyway, just to justify the additional purchase.
 
It would almost seem preferable to try to balance the channels just using the two CMA800R onboard volume knobs, so that you don't introduce additional sound influence or weak link with another amp upstream, especially since the preponderance of them use voltage controlled signal gain. 
 
EDIT:  To answer my own question, the Yulong DA8 and Nuforce DAC-80 seem to be the only ones on your list that are cost effective as a front-end DAC/volume control component addition for the dual CMA800R monoblock configuration.  I would just hope that they would at least hold service for allowing the dual CMA800R sonic attributes to be well displayed. 
 
Altho as an end game set-up, cost is no object, eh?  :wink: 
 
Dec 19, 2013 at 10:26 PM Post #152 of 757
Berkeley Alpha DAC would be a perfect choice. Superb DAC. Superb analog output stage and very well implemented volume control. It is also a balanced design optimized for XLR output, which would make a great feed to XLR monos. Great reviews, and has had high resale value as well. Very much in demand in the audiophile world.
 
Dec 20, 2013 at 9:26 AM Post #153 of 757
  Nice list, and prolly fairly exhaustive to boot, but if one were to lay in such a DAC/amp mostly just to support the CMA800R dual mono configuration, which one(s) would you perceive as the biggest bang for the buck, or at least without introducing significant deterioration of SQ, such as signal distortion or diminished staging, which would kind of defeat the purpose of the dual monoblocks? Your Yulong DA8, such as yzap referred to?  And you'd probably need to multi-task such a component in your audio set-up, anyway, just to justify the additional purchase.
 
It would almost seem preferable to try to balance the channels just using the two CMA800R onboard volume knobs, so that you don't introduce additional sound influence or weak link with another amp upstream, especially since the preponderance of them use voltage controlled signal gain. 
 
EDIT:  To answer my own question, the Yulong DA8 and Nuforce DAC-80 seem to be the only ones on your list that are cost effective as a front-end DAC/volume control component addition for the dual CMA800R monoblock configuration.  I would just hope that they would at least hold service for allowing the dual CMA800R sonic attributes to be well displayed. 
 
Altho as an end game set-up, cost is no object, eh?  :wink: 

 
I only listed stuff which I can confirm is really impressive, or in a few cases have it on very good authority from friends. Of my list I choose the Invicta which is what I use as a reference (planning to upgrade to the Invicta Mirus soon). But the Anedio D2 and NAD M51 are also very, very capable. The Yulong DA8 is quite good as well, though it does impart a subtle warmth that may not be appreciated if one is searching for ultimate transparency. I've heard similar about the MSB Analog - it sounds great, but maybe makes everything more enjoyable than it really should (if that makes any sense at all). 
 
I'm not sure why you chose the Yulong and the NuForce as the only two.... both are good, but so are the others on my list. I just remembered the Nuforce has SE outputs only, so you'd lose the "true balanced" configuration. Might still be nice though, as we've heard prior from the user running the Naim DAC. 
 
Endgame, cost no object setup? For me, probably Invicta Mirus driving dual CMA800R with an HD800. Will try that soon enough and advise!
 
 
  Berkeley Alpha DAC would be a perfect choice. Superb DAC. Superb analog output stage and very well implemented volume control. It is also a balanced design optimized for XLR output, which would make a great feed to XLR monos. Great reviews, and has had high resale value as well. Very much in demand in the audiophile world.

 
The Berkeley is very nice as well. I forgot about it for some reason. I got a press release from them recently which I only briefly skimmed over, but it mentioned (and pictured) their new Reference Series DAC. Might just be the same as their current model but with a more fancy case.... and it would still rock. I think they finally realized the audiophile market is probably bigger for them than the studio professional. 
 
Dec 20, 2013 at 4:19 PM Post #154 of 757
Thanks for all the advice everyone!
 
For the time being, my setup will be as I previously mentioned:
Yulong DA8 (in Pure Dac mode) >> 1 CMA800R >> HD800
 
And I won't have to worry any little bit about pre-amping since I'll let the CMA800R take care of that. That'll keep happy for quite some time, I think. 
bigsmile_face.gif

 
But at some point, I know that the urge to buy more gear will get the better of me (probably after Project86 writes his dual CMA800R monoblock review) and I'll eventually pick up another CMA800R. At that point, I'll do just what Project86 reccomended and hook up the DA8 straight into the monoblocks and use the DA8's headphone amp as a preamp. On a side note, Project86, if you could test the DA8 with the mono-blocks when they eventually both arrive, I would be eternally greatful! 
wink_face.gif

 
Using the DA8's headphone stage as a preamp will most assuredly sound great, but I'll probably always be wondering how it would sound if I was using a DAC that had a volume control only preamp instead of a full headphone amp to do the pre-amping. That being said, I don't think I'll be able to justify spending ~$5k on the Invicta Mira for that sort of setup for many years to come, hehe.
 
Dec 20, 2013 at 4:29 PM Post #155 of 757
Oh, I've also got a few other newbie questions.
 
What's the difference in implementation between just a "volume control" and a headphone amp stage on a DAC? I'm guessing "volume control" is just a preamp while the headphone stage would include both a preamp and an amplifier? 
 
Also, in general, if one uses a headphone amp as a preamp instead of a simple volume control, I'm guessing this is going to result in more of the headphone amp's sound signature coming through when compared the signature of a simple volume control which would probably be more transparent? Or since the headphone amp would be run at such low levels in this case, that it would be mostly transparent too?
 
Dec 20, 2013 at 5:30 PM Post #156 of 757
There's a bit of confusion there, because you aren't using the DA8 headphone amp as a preamp. The DA8 has variable line outputs, which is also referred to as preamp capabilities. Then it also has a headphone amp. The former uses XLR or RCA jacks on the back panel, while the latter is tied to the 1/4" jack on the front. The confusing part is that both are tied together - activated or disabled by pushing the knob, and controlled by turning it. But they really are separate things.
 
In some preamps and/or headphone amps, an analog potentiometer is used to control volume. Or sometimes it's a different form of analog volume control, such as a resistor ladder network. In other cases the solution happens in the digital domain. Which is what happens in the DA8 - they use the internal volume control function of the ESS Sabre DAC chip itself. Each method has positive and negative attributes, and it's really up to the end user if they are satisfied with what they have. I've heard good and bad examples of both types so I'm not biased either way. 
 
Dec 20, 2013 at 7:09 PM Post #157 of 757
   
I only listed stuff which I can confirm is really impressive, or in a few cases have it on very good authority from friends. Of my list I choose the Invicta which is what I use as a reference (planning to upgrade to the Invicta Mirus soon). But the Anedio D2 and NAD M51 are also very, very capable. The Yulong DA8 is quite good as well, though it does impart a subtle warmth that may not be appreciated if one is searching for ultimate transparency. I've heard similar about the MSB Analog - it sounds great, but maybe makes everything more enjoyable than it really should (if that makes any sense at all).
 
I'm not sure why you chose the Yulong and the NuForce as the only two.... both are good, but so are the others on my list. I just remembered the Nuforce has SE outputs only, so you'd lose the "true balanced" configuration. Might still be nice though, as we've heard prior from the user running the Naim DAC.
 
Endgame, cost no object setup? For me, probably Invicta Mirus driving dual CMA800R with an HD800. Will try that soon enough and advise!

 
I mainly selected the Yulong and Nuforce based on their cost, without diving too deep into the technical details.  My thinking was that you're largely looking for an upstream volume control knob for the dual CMA800R amps, and that spending as much or more than what the twin monoblocks cost kinda inverts the priority of that one function.
 
However, if the component cost can be mostly attributed to a DAC upgrade, then comparative costs become secondary to what you consider your end game strategy on technical merits alone.
 
I've also done some more thinking on what role the dual monoblock CMA800R would play now in a pre-amp configuration.  Since we're not talking about the pe-amp being the prelude to a high power output amp for speakers, but more like two successive headphone amps in series, with the first (pre)amp just as likely to influence the final sound as much as the final amp(s), then maybe we can consider the dual monoblock CMA800R configuration as just the finishing or polishing amp to the final headphone input sound.  Adding an additional layer of space and clarity to the sonic detail, so to speak.  Now that might be a worthwhile augmentation to your headphone music, no matter how good, both in SQ and/or sufficient headphone driving power, your first amp in the audio output sequence is by itself alone.
 
As you know, I already have a superb Krell Phantom pre-amp with a SE headphone outlet, that implements current driven amplification circuitry consistent with the sonic advantages offered by the Questyle topology.  So there shouldn't be any significant upstream signal degradation to mask the benefits which might be gained by the dual monoblock CMA800R amp configuration.  And the Krell happens to have an XLR output available which I could now input into a pair of CMA800Rs, so that if nothing else, I can now realize a balanced headphone output out of the Krell, independent of whatever additional microclarity I may be able to achieve from the Questyle amps' signal processing.  Kinda an expensive way of adding an balanced headphone outlet to the Krell, I will admit.
 
But that conceptual promise seems somewhat exciting to me, although I think I dread the cost of the amps interconnect and headphone XLR balanced cables more than the upgrade to dual CMA800R amps.  I wonder what kind of trade-in Alden would give me on my CMA800?
 
Dec 21, 2013 at 10:22 AM Post #158 of 757
I see both sides - yes, spending a lot for that one function (volume control) seems kinda odd. And I suppose it is odd, if you already have a nice DAC and a single CMA800R. You add another CMA800R (which isn't exactly pocket change) and all of a sudden you need to spend big bucks on a simple volume control? Then again, we are talking end-game systems here, so I guess spending a decent amount is just par for the course. 
 
It maybe helps that DACs are progressing so rapidly. So if you maybe own a DAC from a few years back, with no volume functionality, it might be a worthwhile upgrade anyway. Get something newer and better than your current DAC, and the volume control probably comes as a bonus. 
 
As you know, the single CMA800 is already VERY good at showing the true colors of a source component. I can only imagine the dual monoblock setup taking it that much farther. So I guess spending big bucks on it doesn't seem so unreasonable. If one was determined to build the best HD800 rig they could, I'd think this was a very viable option. I'd think your Krell would be an ideal pairing if you ever pick up the monos. Definitely worth an email to Alden if you think it might be a road you want to try. 
 
I wouldn't worry too much about the cable side of it though. You can do quite well for yourself without spending obscene amounts. There are plenty of options out there which won't break the bank - I can have any cables I want, yet I choose relatively affordable stuff from Cabledyne, Toxic Cables, Charleston Cable Co, CablePro, etc. These small firms have exceptional designs and customer service too, without need a second mortgage. Give me those any day compared to Nordost or Shunyata etc. 
 
Jan 4, 2014 at 7:40 PM Post #159 of 757
Mine is here today, sooner than expected. I'm going to unplug my Burson and warm it up, and then rummage around to look for my balanced interconnects.
 
Jan 5, 2014 at 4:01 PM Post #160 of 757
  Mine is here today, sooner than expected. I'm going to unplug my Burson and warm it up, and then rummage around to look for my balanced interconnects.

 
 
Faster than expected shipping is always a nice surprise. Let us know what you think, once you log some hours on it. 
 
Jan 5, 2014 at 5:46 PM Post #161 of 757
Received mine 3 days ago. I'm really impressed so far. Incredible synergy with the HD800 although I'm a bit disapointed with the T1. They are my favorite cans but with the CMA800R the HD800 sound so much better to my ears. When you switch from the HD800 to the T1 it goes from hifi to mid-fi in a second !?! It's strange because with all my previous amps (B22, Soloist, LD MKVI+, V200, WA2, Mjolnir) I prefered the T1. I don't have my B22 anymore and I haven't done a serious side by side comparison with my Soloist but from memory, they are no match for the CMA800R with the HD800.
 
But the biggest surprise for me was the HD650. I've never been a big fan of them but with the CMA800R they sound very very good. By far the best sound I ever heard from them. In fact, with the CMA800R I prefer the HD650 to the T1 !  
 
Build quality is excellent, very impressive. 
 
Anyone noticed a difference between the RCA and XLR input ? 
 
Jan 5, 2014 at 9:59 PM Post #162 of 757
Nope, at least in short term. AFAIK there shouldn't be any, as XLR inputs are desymetrized anyway, those are just for comfort of listener, i.e. if DAC has XLR's only, or its XLR's are better sounding. Had my chat with project86 and he was kind enough to tell me that. Single XLR input for monos asaide, of course. And yes CMA800R is incredible with HD 800. Bakoon'ish sound signature and current amplification really does its trick to my ears. I have Audio-Gd Phoenix, and something tells me this piece is going away, was outperformed by CMA800R, and not by a small margin.
 
Cheers,
00L
 
Jan 6, 2014 at 1:21 AM Post #163 of 757
  Received mine 3 days ago. I'm really impressed so far. Incredible synergy with the HD800 although I'm a bit disapointed with the T1. They are my favorite cans but with the CMA800R the HD800 sound so much better to my ears. When you switch from the HD800 to the T1 it goes from hifi to mid-fi in a second !?! It's strange because with all my previous amps (B22, Soloist, LD MKVI+, V200, WA2, Mjolnir) I prefered the T1. I don't have my B22 anymore and I haven't done a serious side by side comparison with my Soloist but from memory, they are no match for the CMA800R with the HD800.
 
But the biggest surprise for me was the HD650. I've never been a big fan of them but with the CMA800R they sound very very good. By far the best sound I ever heard from them. In fact, with the CMA800R I prefer the HD650 to the T1 !  
 
Build quality is excellent, very impressive. 
 
Anyone noticed a difference between the RCA and XLR input ? 

 
 
Imho, you've discovered the true nature of the T1. It sounds wonderful with a lot of amps, but when you get to the cold, hard truth of it with a brutally neutral amp like the Questyle..... it just doesn't sound all that great. I agree with you and much prefer the T1 from my Violectric V200, or the Icon Audio HP8, or the Analog Design Labs Svetlana II. If I use the CMA800 or to a lesser extent the AURALiC Taurus mkII, the T1 shows its true colors - and I don't care for it.
 
I think I prefer the Matrix M-Stage HPA-2 over the Questyle or AURALiC with the T1. Yes, it's way way cheaper, but the signature is a better match. 
 
Jan 6, 2014 at 4:25 AM Post #164 of 757
Questyle sounds to good to be true, anyway think i will be cancelling my order on Auralic and get Questyle instead. 
After all my favourite headphone are HD800 and are on the way.   
 
Jan 6, 2014 at 2:32 PM Post #165 of 757
John,

How does the CMA800R compare to the V200 on high sensitivity/low impedance headphones like the LA7000? I may pick up another closed headphone like the Alpha Dog or the LCD-XC in the future. Any experience which amp would be better? Thanks.
 

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