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Questyle CMA800 Current Mode amp - Page 7

post #91 of 589

So far I've only had a few hours with my new CMA800R but I can safely say that it's not lacking any bass impact, which was one of my main concerns with this amp. :)
Also I've noticed a slight improvement in dynamics over my heavily modded Little Dot mkIVse which in direct comparison sounds a bit more squeezed.

post #92 of 589

Hey wow, the extra 4 pairs of cone-feet included with the amp make fantastic spinning tops!! They go on forever and stay in the eaxct same spot all the time. Best spinning tops I've ever come across, amazing. Just a fun thing to do, while waiting for the amp to burn in.

 

Yeah I know it's stupid, but for some reason they included eight extra spiked feet. Guess as they had them lying around anyway from the now discontinued CMA800 edition, they might as well send them along as great toys :)

post #93 of 589
Quote:
Originally Posted by SoupRKnowva View Post


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

 

I don't think that Questyle uses the same current transconductance topology as Bakoon or Krell/audio-gd, since they appear to have stumbled upon their particular audio circuit while developing a high speed communications product.  And I think that the CMA800 has the lowest THD+N and TIMD specs of all of them, since its circuit topology seems to have been especially optimized for linear signal gain, based on my listening comparisons.

 

I do think that you're right about the Questyle output being voltage driven, since their lower end CMA600 amp offers options between high impedance and low impedance output modules.


Edited by jacal01 - 11/15/13 at 3:26pm
post #94 of 589

Finally finished my actual review of the CMA800. By now it's obsolete..... sort of. The CMA800R is the new replacement, basically the same thing with slightly more power and better specs, plus the dual-mono option. So everything I say in the review should still apply. I imagine they still have stock of the original CMA800 available since the CMA800R is so new. 

post #95 of 589
That's great news. I would imagine that whatever observations and conclusions you may have gathered on the CMA800 would also apply to the newer CMA800R, since I'm sure that the newer Questyle model still utilizes the same signal gain topology as the base amp, plus whatever additional capabilities and enhancements of the replacement model.

You could always add some updating contingency statements for the newer model where appropriate, bespeaking of the added capabilities and enhancements of the CMA800R where you might have additional knowledge or data, such as when discussing the base amp's disadvantages.

I would also think that the synergy of the Questyle amp and DAC products would also still be true for the CMA800R.
post #96 of 589

Following on from the great review by project86. I am now using two CMA800R in a balanced combination. The sound is nothing short of breathtaking, and worth every penny (or cent). IMO this combination is as good as it gets...

post #97 of 589

Where's the smiley face for :smug:?

post #98 of 589
Quote:
Originally Posted by PETERCALV View Post
 

Following on from the great review by project86. I am now using two CMA800R in a balanced combination. The sound is nothing short of breathtaking, and worth every penny (or cent). IMO this combination is as good as it gets...

Wow! Can you elaborate a little bit more? Which headphones are you using and what differences do you notice from your previous configuration or from using only one CMA800R?

 
Cheers
post #99 of 589
Quote:
Originally Posted by victorcc View Post
 

Wow! Can you elaborate a little bit more? Which headphones are you using and what differences do you notice from your previous configuration or from using only one CMA800R?

 
Cheers

Here is a picture of what I am using this with. I hope it won't be considered too smug showing this:

 

 

I have used the Questyle combination with an Eximus DP1 and Naim DAC (as in the above photo). The Naim is by far the better match for me. I also use HD800 headphones. What is immediately noticeable is the incredibly wide soundstage. I have never heard anything that good before from headphones (or speakers for that matter). I have only had this combination for just over a week, so I am still coming to terms with it.

post #100 of 589

How can that set up can be balanced? I don't think the V1 has balanced out, only RCA out with shared ground, or I am missing something? :confused:

post #101 of 589

I was about to ask the same question. Doesn't it require two balanced xlr inputs for it to run in full balanced mode?
 

post #102 of 589
Quote:
Originally Posted by PETERCALV View Post
 

Here is a picture of what I am using this with. I hope it won't be considered too smug showing this:

 

 

I have used the Questyle combination with an Eximus DP1 and Naim DAC (as in the above photo). The Naim is by far the better match for me. I also use HD800 headphones. What is immediately noticeable is the incredibly wide soundstage. I have never heard anything that good before from headphones (or speakers for that matter). I have only had this combination for just over a week, so I am still coming to terms with it.

Wow, lucky you, congratulations. Silly question really but do you think it may be your end game amp set up?

post #103 of 589

Don't be silly! You know there is no such a thing in the audio world. ;)

 

Quote:

Originally Posted by SebastianL View Post
 

I was about to ask the same question. Doesn't it require two balanced xlr inputs for it to run in full balanced mode?
 

Unless the new 800R has the ability to balance its SE input (using trafos or opamps), otherwise it is only a dual mono set up.

post #104 of 589
I was gonna say the same - when running from the Naim DAC, I'd call this a dual mono setup rather than a fully balanced one. The Eximus could make it fully balanced. But hey, if you prefer the V1 in the chain, then it doesn't matter what label we give it!
post #105 of 589

Hi guys,

Let me be out of topics.

The industry is now in right track for the science for a drive amplifier design for speaker motor, which is mostly driven not by voltage but current.

The current generates magnetic flux density or pressure that is directly related to sound pressure.

When the phone coils are driven by voltage in audio signal band, the phase between driving and driven may widely vary with for frequency range aka impedance.

It will be well emphasized in dynamic driver due to inductance presence, but will be reduced in ortho.

Regardless of the driver type, the current driven amps see no phase distortion, which is functionally equivalent to jitering.

 

For this regards, Bakgoon, Questyle, Audeze, and Hifiman are in right direction.

However dynamic drive can also enjoy no phase distortion for entire signal band, but mechanically induce phase delay is inevitable with dynamic driver.

For now I need save for a Qstyle in some time for my LCD-2.2 and He-5Le.:biggrin: 


Edited by Joong - 12/4/13 at 1:41pm
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