[Mython]

I did contact someone within Questyle and they reaffirmed that we will see the production versions at Munich for the High End show and at THE Show Newport next month. Looks like they're close to finalizing the UI. I can't wait to get one in my hands and put it through the paces.

 
 
                     

 

 

[514077]

Confused, surely Optical out is digital not analogue! To a DAC/Amp should the owner wish.

Not necessarily a dealbreaker.  I've just read enough on various threads to have decided to prefer co-ax.  More likely to get higher resolution than from optical which sounds kinda chancy and frig-aroundish.  I actually like the sound of my current (no pun intended) player into my Hugo by co-ax than my USB from the computer.

 

[514077]

  Maybe I'm confused.  I thot I'd read from one of the Questyle MOT posts that it was it was an analog line out (volume bypass), no digital output being offered (re. USB DAC option question?).  I could be mistaken, but my original point remains intact, i.e. why would you want an intermediate output in a portable configuration, esp. bypassing the QP1 amp section?  If using the DAP in some kind of multi-component desktop or home setup, the potential fragility of an FO interconnect cable would be a non-issue.
 
Personally, I don't see that the DAC section of this DAP would be any unique contributor in a multi-component audio train, being your basic delta/sigma chip, even if multi-bit.  I doubt even if the digital filter being used is any off-chip optimized programmable configuration, such as FPGA or DSP.  Perhaps there is some sonic advantages to be gained via direct DSD data processing.
 
If you targeting the QP1 just as a audio file transport, in conjunction with an external DAC/amp, then there's a plethora of cheaper alternatives.  Perhaps the 2 x micro SD card external memory capability offers some advantage.

The 1st reason for my interest is the two card slots.  I never carry around a dap/amp combo, (not since I put away my old IPod).  When I'm home, I use my dap as a transport or not; depending.
Another reason for my interest is that I'm given to understand that the QPs are wheel-and-button rather than the acursed touchscreen which is difficult to impossible for me to use.
And optical is a digital type of output. 
The more I type about it, the less offputting is the thought of optical, I guess.
I'm just not quite sure what the current output brings to the table although I've heard people seem to like the idea.  Could one explain?
Thanks.

 

[jacal01]

You're right.  FO cable has always been for digital output.  And transport output makes the most sense, since it would serve as a convenient front end with your playbill of choice for evaluating and comparing external DAC and amp combos.  Having a source SPDIF input to a DAC is a big advantage in itself, given how many digital data conversions are notoriously badly implemented in DAC USB inputs.  The main problem with fiber is not its fragility, but the fact that you need an externally powered media converter to change from fiber to coax SPDIF for those DACS without Toslink digital input.  That pretty much in itself  precludes using the QP1 as a portable front end to a portable external DAC/amp equipped with only coax or USB digital input.  Perhaps the QP1 can be upgraded later for OTG USB input/output, given the current abundance of portable and transportable USB DAC and DAC/amp products.
 
Myself, I favor the micro BNC connector for its small footprint and matched cable impedence, but it does take dedicated space in a crowded DAP real estate, however small, so manufactureres will always favor the dual use 3.5 mm coax/optical TRS jack connector for its single port and double output capability.  Get used to it.

 

[DGCFAD]

  I don't get it.  The optical output is for analog line out, which is for connecting another amp in series, and not your usual all-in-one portable DAP setup, unless you're into brick stacking components with an elastic band.  Which hardly plays to the strength of this DAP unit, namely its current mode amplification.  Why would you want to add another amp after it, which would most likely be a portable opamp chip type, anyway?  To add color and/or distortion?
 
And there are robust jacketed fiber optic cables available, should you desire.  I'm just not seeing this particular issue as a deal breaker.

Ok, the line output is a multi-function connection. It is a coaxial fixed level or variable level analog line output for running into an external amplifier, and it also has an optical digital output for running to an external DAC.

 

[DGCFAD]

  Maybe I'm confused.  I thot I'd read from one of the Questyle MOT posts that it was it was an analog line out (volume bypass), no digital output being offered (re. USB DAC option question?).  I could be mistaken, but my original point remains intact, i.e. why would you want an intermediate output in a portable configuration, esp. bypassing the QP1 amp section?  If using the DAP in some kind of multi-component desktop or home setup, the potential fragility of an FO interconnect cable would be a non-issue.
 
Personally, I don't see that the DAC section of this DAP would be any unique contributor in a multi-component audio train, being your basic delta/sigma chip, even if multi-bit.  I doubt even if the digital filter being used is any off-chip optimized programmable configuration, such as FPGA or DSP.  Perhaps there is some sonic advantages to be gained via direct DSD data processing.
 
If you targeting the QP1 just as a audio file transport, in conjunction with an external DAC/amp, then there's a plethora of cheaper alternatives.  Perhaps the 2 x micro SD card external memory capability offers some advantage.

Personally, I use my QP1 in my car via the line out, but if I didn't have a CMA800i, I could see using it as a DAC/preamp in my home system. We use the optical output as a source for our 5GHz Wireless Systems at shows. Essentially the idea is to use it as a portable music server, able to run headphones, or into your car stereo and when you get home, you can just plug in the optical cable and run your home system.

 

[DGCFAD]

 
The 1st reason for my interest is the two card slots.  I never carry around a dap/amp combo, (not since I put away my old IPod).  When I'm home, I use my dap as a transport or not; depending.
Another reason for my interest is that I'm given to understand that the QPs are wheel-and-button rather than the acursed touchscreen which is difficult to impossible for me to use.
And optical is a digital type of output. 
The more I type about it, the less offputting is the thought of optical, I guess.
I'm just not quite sure what the current output brings to the table although I've heard people seem to like the idea.  Could one explain?
Thanks.

If you are using the digital output rather than the analog output, the current mode amplification does not come into play.

 

[jk47]

 
If you are using the digital output rather than the analog output, the current mode amplification does not come into play.

i think the question, which i share, is: what are the advantages/disadvantages of a current amp compared to a voltage one?

 

[JML]

Look at this thread:  http://www.head-fi.org/t/692923/review-questyle-cma800-current-mode-amplifier

 

[514077]

 
If you are using the digital output rather than the analog output, the current mode amplification does not come into play.
Sorry.  I should have put the current question in a separate post.  I was just wondering as an aside, what's the advantage of a current amp?  I hear positive reports about that kinda amplification; just wondering what it is exactly?

 

[DGCFAD]

  i think the question, which i share, is: what are the advantages/disadvantages of a current amp compared to a voltage one?

 

 

The short answer is that Current Mode Amplification has a wider bandwidth and eliminates Transient Inter-modulation Distortion (TIMD) which is what gives solid state amps that metallic sound. How it does that is a little more complex. In conventional amplifiers, the signal is modulated in voltage mode, which is relatively slow, reducing the slew rate and limiting usable bandwidth. In the majority of amplifiers, THD is reduced using a negative feedback loop, the draw back of which is that the slew rate is not fast enough to correct distortion on transient signals, creating TIMD. Current Mode Amplification modulates current rather than voltage, which is 100 times faster, eliminating TIMD by pushing it out of the audible spectrum, much in the same way that oversampling eliminates digital noise in a DAC. The disadvantage of Current Mode Amplification is that it does not work well with a variable impedance load (like a speaker), so we convert back to voltage mode at the output stage, though no signal amplification occurs in voltage mode. In practical terms, the disadvantage of Current Mode Amplification is a more detailed, less distorted and colored signal which may not appeal to some, especially with headphones designed to compensate for such shortcomings in other amplifiers.

 

[x RELIC x]

So, in layman's terms, caveat emptor............ You may not like what you see(hear) when you remove the (audio)beer goggles!

Sounds good to me.

 

[514077]

   

The short answer is that Current Mode Amplification has a wider bandwidth and eliminates Transient Inter-modulation Distortion (TIMD) which is what gives solid state amps that metallic sound. How it does that is a little more complex. In conventional amplifiers, the signal is modulated in voltage mode, which is relatively slow, reducing the slew rate and limiting usable bandwidth. In the majority of amplifiers, THD is reduced using a negative feedback loop, the draw back of which is that the slew rate is not fast enough to correct distortion on transient signals, creating TIMD. Current Mode Amplification modulates current rather than voltage, which is 100 times faster, eliminating TIMD by pushing it out of the audible spectrum, much in the same way that oversampling eliminates digital noise in a DAC. The disadvantage of Current Mode Amplification is that it does not work well with a variable impedance load (like a speaker), so we convert back to voltage mode at the output stage, though no signal amplification occurs in voltage mode. In practical terms, the disadvantage of Current Mode Amplification is a more detailed, less distorted and colored signal which may not appeal to some, especially with headphones designed to compensate for such shortcomings in other amplifiers.

The disadvantage sounds great in that I prefer clear sound to warm, anyway.
And, ya know, I rarely use a direct coax/optical output either.
I was reading on Inner Fi that John Grandburg may be posting his thoughts on the QP1, when it's out.  Looking forward to the release.
Just one more thing.  Does the player have 'folder' view?

 

[goodvibes]

Heard these today. The basic model seems a real value and the up model a bit more refined and delineated. These were not finished products in few ways and were only at axpona for audition purposes. Character was smooth, warm and controlled. The up model was not 'oh my god' better. More for a critical ear difference. Says more about the basic one that the up model. I don't think they were yet as good as the best over $1k players as they were just a wee bit 'full' sounding ( certainly not congested or lacking in detail and plenty open). I would say they sounded as good as anything I've heard at their price points, depending on one's preference. They'll likely make some other players seem less in control and a bit ringy. I could see these developing a strong following. They're certainly the right size and beautifully made which along with their sound aids in their perceived value.

 

[audionewbi]

  Heard these today. The basic model seems a real value and the up model a bit more refined and delineated. These were not finished products in few ways and were only at axpona for audition purposes. Character was smooth, warm and controlled. The up model was not 'oh my god' better. More for a critical ear difference. Says more about the basic one that the up model. I don't think they were yet as good as the top spread as they were a bit 'full' sounding ( certainly not congested or lacking in detail and plenty open). I would say they sounded as good as anything I've heard at their price points, depending on one's preference. They'll likely make some other players seem less in control and a bit ringy. I could see these developing a strong following. They're certainly the right size and beautifully made which aids in their perceived value.

did you have your lotoo with you?