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Questyle CMA800 Current Mode amp - Page 6

post #76 of 428

if you look for it on ebay,you can find it.

post #77 of 428
Quote:
Originally Posted by jacal01 View Post
 

You have to understand that there are no losers here.  The nice thing about current driven amps is that they appear to be tolerant with most if not all headphones, regardless of impedance. Impedance matching does not seem to be all that essential, very likely because the output signal current drives the heaphones ("push"), rather than the output voltage inducing the signal current through all the system impedances ("pull"), implying impedance matching is more critical.  Or so it once made sense to me...

 

Comparing the CMA800 and HPA-21 amps, using the same DAC and source material, the CMA800 seems to be somwhat brighter, more airy, with the HPA-21 darker/warmer.  The HPA-21 seems to have more body and texture in the mids and middle bass regions.  However, the CMA800 appears to have slightly more bass extension, however thinner.  Weird that.  And the CMA800 seems to actually have less distortion than the HPA-21; the notes and vocals are crisper, more articulate.  The HPA-21 also seems to run a bit hotter, for what that's worth (Class A?).

 

Having said all that, there seems to be a special synergy with the CMA800 and my LCD-2s. I believe this extraordinary match is because of pairing a brightish amp with darker headphones.  Remember, we're talking nuances here, not glaring attributes.  But it's a very good resulting tonal meld which is quite pleasing to the ear.  Of the two amp pairings with the LCD-2, I feel the CMA800 combo is more euphonic, at least to me.

 

However, I think that the HPA-21, because of producing fuller audio in the mids and mid bass frequencies, does offer the advantage of better approximating the euphonic tube sound of lots of mids bloom.  If you relish more the warm lush sound of tube amps, then the HPA-21 ascends over the CMA800.

 

I think that the CMA800 offers exceptional SQ value at whatever price point it's finally introduced at in the US.  I anticipate a US distributor to be in place and product exhibition by RMAF 2014.  Meanwhile, you can most likely purchase one factory direct by contacting Questyle (Alden Zhao) and inquiring.  Payment will need to be via bank wire transfer.

 

 

Thanks for that info. I don't have a Bakoon here to compare but throwing the CMA800 up against the Violectric V200, AURALiC Taurus, Analog Design Labs Svetlana II, and Icon Audio HP8 mkII (all excellent amps in the $1000+ range), I find the CMA800 to hold ground very well. It's just got such a killer sound to it that seems almost unique. But then again each of them has their own character.... but CMA800 is definitely up there with the best of them.

 

I'm working on my full review for InnerFidelity and hope to have it up soon - more people need to hear about this gem!

post #78 of 428

jacal01 thanks for sharing your thoughts on the CMA800 vs. the Bakoon. That post was exactly what I  was looking for.

This leaves me in a bit of a spot though. Being a tube-fan I think the Bakoon is more in sync with my ideal sound but the CMA800 suits my wallet a little better :)

 

@project86
I used to own a Violectric HPA-V181 which I sold because my heavily modded Little Dot MKIVse sounded marginally better with my LCD-2s. Even running the Violectric fully balanced all the way from the source to the cans using an expensive Zeus OCC Copper balanced aftermarket cable. With the LD I just use the Audez'e stock cable.
What I liked about the Violectric though was its blackground. Stll I preferred my LD by a slight margin.
As the V181 and V200 are very close in SQ, I hope the CMA800 is a significant upgrade from the V200? Or else I don't really understand the fuss about the CMA800. 

post #79 of 428
Quote:
Originally Posted by SebastianL View Post
 

 

 

@project86
I used to own a Violectric HPA-V181 which I sold because my heavily modded Little Dot MKIVse sounded marginally better with my LCD-2s. Even running the Violectric fully balanced all the way from the source to the cans using an expensive Zeus OCC Copper balanced aftermarket cable. With the LD I just use the Audez'e stock cable.
What I liked about the Violectric though was its blackground. Stll I preferred my LD by a slight margin.
As the V181 and V200 are very close in SQ, I hope the CMA800 is a significant upgrade from the V200? Or else I don't really understand the fuss about the CMA800. 

 

Well, I do like the V200 more than V181. And I do like the CMA800 more than the V200, at least with certain headphones. That should be considered a big deal because the V200, for me, is one of the best amps out there. Maybe you just didn't get on with the Violectric house sound as much as I do. 

post #80 of 428
The V181 is not a bad amp, it just got hyped too much in the 'best amp for the LCD-2' thread.
The funny thing is that my LD tube amp and the V181 weren't far apart in sound signature. Mind you that I have spent years tube rolling and modding the hell out of the little chinese amp. But I just can't say that the V181 is something special.

Btw. the best I have ever heard my LCD-2 (rev. 1) was straight out of a Totaldac's headphone out! A SS circuit inside the r2r-ladder converter. (And I'm usually a tube fan.) The treble wasn't recessed at all. Everything sounded crystal clear and had just the right balance.
That's why I know it's possible to make the LCD-2 sound just the way I want it to sound. I have the right DAC, I just need the proper amp for it. That amp may be a current mode amp.
post #81 of 428

John-how does the CMA800 compare with the Taurus with the HD800s? Been eying both of these lately for some reason...

 

-Daniel

post #82 of 428
Quote:
Originally Posted by BournePerfect View Post
 

John-how does the CMA800 compare with the Taurus with the HD800s? Been eying both of these lately for some reason...

 

-Daniel

 

Working on figuring that out now. I'd like to finish reviews of both models soon but stuff keeps getting in the way. 

 

For HD800 I gotta say - though both are excellent, CMA800 has a special synergy for me. Clarity is just unbelievable, and it's not annoying, bright, zingy, etc, as the HD800 has potential to be. Having said that, the Taurus is definitely appealing as well, in its own way. HE-6 for example, though the CMA800 does a great job with it, sounds the best I've ever heard through the Taurus. 

post #83 of 428

Seeing as I'm gonna pick up an HE6 again soon-that doesn't help! :tongue_smile: Thanks John.

 

-Daniel

post #84 of 428
Quote:
Originally Posted by project86 View Post
 

 

 

Thanks for that info. I don't have a Bakoon here to compare but throwing the CMA800 up against the Violectric V200, AURALiC Taurus, Analog Design Labs Svetlana II, and Icon Audio HP8 mkII (all excellent amps in the $1000+ range), I find the CMA800 to hold ground very well. It's just got such a killer sound to it that seems almost unique. But then again each of them has their own character.... but CMA800 is definitely up there with the best of them.

 

I'm working on my full review for InnerFidelity and hope to have it up soon - more people need to hear about this gem!

 

I think its the current driven amp doing its magic.  That low distortion crystal clarity is so seductive.  It is somewhat too bad that you don't have more exposure to the different current amps for like comparisons, tho.  I actually bounce between the CMA800, my Bakoon and my Krell on a fairly routine basis, depending on my predilection of the moment.  I've got my individual headphones paired with my amps of choice for optimum synergy, so that I really select a combo each time. It seems to add variety based on the DAC/amp/HP different characters, as you say, that my mood and music can resonate with.  I'm probably spoiled.


Edited by jacal01 - 10/31/13 at 6:48pm
post #85 of 428
Just saw this thread and the current mode thing piqued my interest quite a bit.

From reading the entire product page, it would seem that it's just a current gain amp, with a normal voltage output. Which makes sense as otherwise it wouldn't work well with anything but headphones with flat impedance curves.

Still in interesting amp though...
post #86 of 428
Quote:
Originally Posted by SoupRKnowva View Post

Just saw this thread and the current mode thing piqued my interest quite a bit.

From reading the entire product page, it would seem that it's just a current gain amp, with a normal voltage output. Which makes sense as otherwise it wouldn't work well with anything but headphones with flat impedance curves.

Still in interesting amp though...

 

 

Nope, it's a transconductance amp - voltage input, current output. Their "TransLinear Loop" circuit means headphone impedance is not an issue. Or at least that's been my experience, and that's what I make of their engineering descriptions so far. They are still translating some things for me so I can complete my review at InnerFidelity. 

post #87 of 428
Quote:
Originally Posted by project86 View Post


Nope, it's a transconductance amp - voltage input, current output. Their "TransLinear Loop" circuit means headphone impedance is not an issue. Or at least that's been my experience, and that's what I make of their engineering descriptions so far. They are still translating some things for me so I can complete my review at InnerFidelity. 
I'd be willing to admit that I was wrong, but that's my impression from reading the website. Just ask them what the output impedance is, that will answer the question for sure
post #88 of 428
Quote:
Originally Posted by SoupRKnowva View Post


I'd be willing to admit that I was wrong, but that's my impression from reading the website. Just ask them what the output impedance is, that will answer the question for sure

 

No problem, it's definitely a bit more confusing than dealing with a more conventional design. I have lots of questions that they are working on answering for me. 

post #89 of 428

OK, so I have to eat my words - and rethink my entire approach to this amp. The output is indeed in the voltage domain. So they use a current mode gain stage followed by an I/V converter. Still trying to figure it all out, and the language barrier becomes an issue for technical stuff. 

post #90 of 428
Quote:
Originally Posted by project86 View Post

OK, so I have to eat my words - and rethink my entire approach to this amp. The output is indeed in the voltage domain. So they use a current mode gain stage followed by an I/V converter. Still trying to figure it all out, and the language barrier becomes an issue for technical stuff. 
Good to have confirmation. The fact that it lists an output buffer after the transconductance current gain stage is what made me think it was standard voltage output. Audio GD amps have been doing something similar for years now. Makes me wonder how they got patents for it as well, since the satri circuit not to mention krell and audio gd have been doing it for quite a while. Make it sound just like marketing fluff to me.

Anyways, I'm still excited to read your review and see how it sounds
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