Review: Questyle CMA800 Current Mode Amplifier
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Zkadoush

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Thanks again for the observation, project86.
I wish I could audition the Questyle myself, and next to the V281 and the Taurus. Anyhow, I will have a go at the 2 Bakoon Amps vs the Taurus in a pair of weeks, and that will certainly put some pressure on the Taurus (will post pics and impressions).

Cheers
 
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Zkadoush

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That's a good start at least, for direct comparisons. Should be illuminating.

Computer Lounge here in Auckland, where I was fortunate to have a go at the Taurus, the BHA-1 and the WA2, along with HD 800s, LCD-Xs, LCD-3s and HE-6s, is bringing in a V281 (VC1 option), so in the very near future I'll be able to audition Fried's mighty new flagship, and compare it directly to the Taurus and a pair of Bakoons that are also on their way. Very much looking forward to that.

My best compliments and thanks go to the passionate head-fier at Computer Lounge, who has amassed an amazing bunch of gear, and who does a fabulous job touring you through the different flavours and technicalities of these components.

I'll be reporting back on my impressions as soon as I get to spend a session with the above mentioned contenders for my desktop and headphones.

Cheers
 
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Zkadoush

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Nice review!
 
Looking forward to your comments on using it with LCD-XC! Will you try it with LCD-X also?

 
 
 
Thanks! I'll definitely give it a try when those arrive.
 
Any impressions on the CMA800R running the LCD-Xs (vs Taurus & V281)?

Cheers
 
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project86

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Not sure who that question was directed at, but if it was to me - I have only heard LCD-X once in someone else's system So no impressions from me, unfortunately. 
 
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Zkadoush

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  Not sure who that question was directed at, but if it was to me - I have only heard LCD-X once in someone else's system So no impressions from me, unfortunately. 

Was intended for you, project86. I thought you would have had a go at the LCD-Xs with the CMA800R.

I was also curious about the personalized specs sheet the CMA800R comes with. I don't recall if you or Srajan Ebaen mentioned that Questyle does some 30 audio measurements on each CMA800R before shipping it to customers, and I was curious about the crosstalk measurements of the CMA800R. Any info on that, or the possibility to ask the manufacturers?

Cheers
 
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project86

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Yeah I currently have an LCD-2 and an LCD-3 Fazor here, and just sent an LCD-XC loaner back.... but no LCD-X. Can't have everything at once I suppose (and my wife would kill me if I did). I'm fairly certain the X would work well based on the performance I get with the other 3 models. 
 
I'll dig out my spec sheet and grab a pic. Might take me a day or two though. I have the one for the CMA800i on hand but the others might be in storage. 
 
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Zkadoush

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  Yeah I currently have an LCD-2 and an LCD-3 Fazor here, and just sent an LCD-XC loaner back.... but no LCD-X. Can't have everything at once I suppose (and my wife would kill me if I did). I'm fairly certain the X would work well based on the performance I get with the other 3 models. 
 
I'll dig out my spec sheet and grab a pic. Might take me a day or two though. I have the one for the CMA800i on hand but the others might be in storage. 

My guess would be the same, but a second opinion and specs surely doesn't hurt, and since there are no output power measurements listed for other loads (like 16, 32, 60, 120, 600 or the 22Ohms of the LCD-Xs), I thought it would be interesting to see the spec sheets provided by Questyle, which as described should be the most thorough provided with a component AFAIK.

Thanks again for your response and kind offer to post the CMA800 spec sheet, looking forward to checking them out.

Cheers
 
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Sanlitun

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For most of this year I have been using my LCD-X with the CMA800R as my default setup and I like it better than the sound from the HD800. The tone is just right and natural, and it doesn't seem transposed or give you the ear against a tweeter feeling you sometimes get from the HD800. That said I don't think I have ever heard better sound from the HD800 than with the CMA800R.
 
One issue with the LCD-X is that they are very sensitive and you do not have a lot of play with the volume. I can lower the output level without introducing loss on my DAC and that helps a lot, and if your DAC doesn't have a variable output you may have trouble.
 
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project86

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I find that variable output on a DAC (of sufficiently high quality) comes in handy rather often. Trimming a few dB here and there can sometimes make the difference between overly touchy and just right, depending on the amp and headphones in use. 
 
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Zkadoush

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Hi project86,

Any chance of seeing those measurements charts?

No meaning to be a pain, just very curious about those measurements, and especially crosstalk specs.

Cheers
 
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Chris J

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Sorry man, but that whole voltage mode, current mode, voltage mode thing looks like a pile of marketing spin.
It is not unusual to describe a basic transistor (Bipolar Junction Transistor) as Voltage in, current out.
Or a JFET either.
Or a MOSFET or a Tube.
Or you can model a BJT as Current In, Current out.
 
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Puzzles

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Sorry man, but that whole voltage mode, current mode, voltage mode thing looks like a pile of marketing spin.
It is not unusual to describe a basic transistor (Bipolar Junction Transistor) as Voltage in, current out.
Or a JFET either.
Or a MOSFET or a Tube.
Or you can model a BJT as Current In, Current out.
 
[...] Sonically, Bakoon and Questyle make up a particular sonic flavor. 
 
[deleted – That wasn't a brilliant performance of my memory.]
 
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Chris J

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Yes and no. Sonically, Bakoon and Questyle make up a particular sonic flavor. Technically, they are based on the same principle, but differ in final execution. [Spoiler alert: I'll very probably tell crap. I just repeat what I picked up here and there]. I think it was called transimpedance or transconductance (or concordance, I don't remember). Such amps basically don't amplify the signal like conventional amps, that is, they don't copy and boost the input signal's voltage/current. They rather unblock the output current that wants out the whole time but is blocked by the input signal. No input signal, no way out. The stronger the input signal, the lower the resistance that impedes the output, and the more current can flow to the headphone. There is no upscaling of the input needed as the voltage is preset by the potentiometer, but the current is limited by the input. It reminded me very much of signal transmission in the eyes. Actually, the signal towards the brain is constantly turned on but the way is blocked until there is some light that triggers those blockades to free the way.
The stupid thing is that Questyle copies the transimpedance signal and uses a conventional signal (whatever that means). But sonically, it results in a similar sound to Bakoon amps. BTW, Grace and BMC use the same principle in their DACs. It's not that special either.

Actually, yes they do amplify the input voltage.
You can either take the input voltage and convert it into current or take the input voltage and create an output voltage.
 
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