Interesting DAC/ headphone amp option for B2

[Davywhizz]

Hi all

This is about the Fiio K5 Pro (link below) DAC/headphone amp/preamp which I think is ideal for integration with the B2 in a range of ways.  

LINK: https://www.fiio.com/k5pro

The K5 Pro (not to be confused with their earlier K5 model) is primarily a DAC/headphone amplifier. I'd been looking for one for a while, to use with my higher impedance headphones. I'd found, as many do, that most dedicated hifi headphone outputs are just not  powerful enough for headphones which are harder to drive.

I'd been interested in the Fiio company for some time.  One of its stated ambitions is to improve the reputation of "made in China" and I sensed a genuine commitment to good design and manufacturing standards, which was supported by the company website and the many positive reviews I read of the K5 Pro. So I ordered one from Amazon, though it was supplied by a Fiio re-seller called the AV Shop, and have been very impressed. 

You have a choice of three input options on the back: optical/coaxial, USB and analogue RCA (if you just want to bypass the DAC and use the preamplifier section). You could leave three devices plugged in all the time, then select between them using one of the toggle switches on the front panel. 

There's another switch on the front to select three levels of gain, to match your choice of headphones. The big volume knob (it's also the on-off switch) has a ring of light around it, which changes colour depending on the resolution of the audio signal. The headphone socket is 6.3mm, but you get a 3.5mm adapter in the box. 

Finally, there are RCA outputs on the back, as well as all the inputs, so you can send the analogue signal to powered speakers or a hifi amp. There's a recommendation to unplug your headphones when using speakers, as you might accidentally overload them if you crank the volume. I think it's unusual that the headphone output stays live when the line out is used, but it does.

With my reference headphones I'm getting all the volume I need, good stereo imaging, excellent detail and separation of instruments and voices. The timing is good too. I can't hear any background noise between tracks. 

A lot of thought has clearly gone into the design, including of the (included) power supply: more detail on that in the link above for the technically minded. I've listened to all the familiar tracks, some in high resolution, which I use to audition speakers and the K5 Pro passes all the tests very well. Maybe I should say it's "great for the price" (150 pounds/dollars) but I don't like to, it's great regardless and looks the part too. Is it really a "Pro" piece of kit? Not really (how could it be?) but not too far away.

[PMB]

Hi Davywhizz,

Thank you for the feedback on the FiiO. Looks an interesting device.

Paul

Brennan Support.

[JAC]

Hi, and glad you found a DAC that worked well.

My experiences have been mixed.  I tried an Optical input  "eSYNiC 192 kHz DAC Converter" which has a volume control and headphone jack.  It worked OK on its RCA analogue outputs, but produced laughable levels of second harmonic distortion on the headphone output at any reasonable output level.  Clearly the designer didn't know what they were doing.  For these tests I used my 1990's Alan Parson's "Soundcheck" Test CD (remember those) and an oscilloscope. Pity really, as it's a smart looking thing.

The next Optical DAC I tried was a £10 cheapie from ebay.  You know the ones, about the size of two matchboxes stacked. No headphone option, just RCA line outputs. The sound quality was surprisingly good, but the output from the DAC had minimal filtering.  I am suspicious that the high level supersonic components pushed out by such devices may give some audio power amplifiers a hard time, depending on their own internal filtering or lack of.  This might explain why people are sometimes disappointed.  Remarkably, inside the DAC were PCB tracks for a passive low pass filter which were bridged out. I was able to design a suitable filter with one inductor and two capacitors per channel, and fit the components into the spaces. I'm now entirely happy with sound quality.

It seems to me that quite a lot of far east gear has been poorly designed or executed and never tested.  A bit like a restaurant where the chef never tastes the food !

[Daniel Taylor]

For £10, I wouldn't expect much design.  ;o)  It's interesting that they left space for a filter and that you found it and took advantage - well done.