My devices on Tour

[jkeny]

I had promised to do this in the New Year & here it is. I see a number of forum members in two minds about the investment - maybe this will help them decide?

I'm happy to send out on tour my 3 current devices for auditioning in people's homes & systems.

The 3 devices in question are:
- a JKSPDIF MK3 - which is a device that takes digital output from the USB port of a computer & outputs SPDIF which can be plugged into any DAC.
- a JKDAC which is the MK3 device combined with a 24/192 DAC (Sabre DAC chip) which takes digital from the USB port of a computer & outputs analogue audio suitable for the input of any amplifier or preamplifier
- a JKDAC32 which is the MK3 device combined with a 32/384 DAC (Burr Brown DAC chip) which takes digital from the USB port of a computer & outputs analogue audio suitable for the input of any amplifier or preamplifier

The way I thought this would be best organised is to post your interest & the device you want to audition in this thread. I reckon a week would be long enough to audition in your system. After which time I expect you send it on to the next person in the list.

Here are the rules I wish to follow:
- this is only open to active members on this forum known to the mods
- the person accepts responsibility for the care of the device while in their possession
- the person takes responsibility for the delivery of the undamaged device to the next person in the list - either by hand delivery or registered post.
- A damaged or unworking device is immediately reported to me
- Finally, I would anticipate that the person would post their impression of the device once finished with it

Phew, didn't think there would be that many points to make :)

[jkeny]

Here's a synopsis of what's required to use one of these devices:
I will supply:
- JKDAC32/JKDAC/JKMK3
- 12 V Power Supply
- USB connectors for direct USB connection (this is a new thing not mentioned before - it improves the sound compared to a USB cable)
- USB cable (Wireworld Ultraviolet)
- RF attenuators (10dB & 15dB) for attenuation of the digital signal (for the JKMK3)
- box & packaging to contain the above

You just need to provide:
- laptop with Jplay (demo is downloadable from here http://www.jplay.eu)
- some audio files copied to disk (in WAV or FLAC format) using Exact Audio Copy
- analogue cables for DACs (or SPDIF cables for JKMK3)




Here's the user guide I send out with every DAC. Hopefully it will be of help to anyone contemplating an audition.

JKDAC32 User Instructions

Contents:
The package should contain:
JKDAC32 USB DAC in aluminium box

The User Supplies:
A 9V to 15V DC power supply through a 2.1mm barrel plug. This is plugged into the DC socket on the JKDAC32. The center pin is the positive terminal. These power supplies are commonly found as surplus PS in people’s homes

Initial Setup:
Download the appropriate M2tech driver for your computer (Apple or PC) http://www.m2tech.biz/hiface.html#driver
Install the Hiface driver for your operating system as you would any driver. The Young DAC drivers may also be used – instructions for installing it are here
Connect a suitable USB cable between the USB port (USB type A socket) on your computer & the USB port on the JKDAC32 (USB type B socket)
Turn on the JKDAC32 – blue LED should light up. The unit is supplied half charged.
It should now be recognised as a soundcard by your computer.
You may have to set the system default audio device to the Hiface AND/OR set the audio output in your audio playback software to the Hiface.
Choose the best output for your playback software ( Kernel Streaming or WASAPI for Windows).
Connect suitable analogue cable between the JKDAC32 & your amplifier or preamplifier
Now you should be ready to play music.
Sometimes when you initially connect the JKDAC32, there may be no sound – it simply needs to be turned off & IMMEDIATELY back on again. There is an initialisation timing issue which only sometimes occurs at turn on.

Recommendations:
The best source to use is a laptop rather than a PC. A laptop seems to have better controlled EMI radiation & you can also run it from its battery (see next).
It is best to not ground the laptop i.e if you notice a better sound when you run it from its internal battery then you have a grounded laptop charger.
If the sound has a haze (& slight hum) in the background when the laptop charger is plugged in but not when running off battery then you should do the following:
You should disconnect the ground of your laptop charger if you want to be able to use it with your charger plugged in & not suffer any noise issues as above. The best way to do this is to get an adapter socket that can be opened up & take out the ground connection. Be sure to mark this adapter as one that has no ground so that you only use it with the laptop.
The JKDAC32 doesn’t draw power over the USB cable & as a result any reasonable USB 2.0 cable will suffice. There is no need for “audiophile”, high priced USB cables although some report improvements in sound with these cables.
On the PC, I recommend the playback software, JPlay as easily the best sounding playback software I have heard. A demo version of this software is available for download here
Kernel Streaming (KS) seems to handle computer memory better than Wasapi?
Use DPlatency to check your computer's optimisation for audio use
If copying a CD to the computer, it should be done with Exact Audio Copy or dbPoweramp. This ensures a perfect copy even if the CD is scratched.
I recommend trying the M2tech Young DAC driver as an alternative to the Hiface driver – not only will it give you 32/384 instead of 24/192 operation but it also sounds different – see here
I find WAV sounds slightly better than FLAC but this is up to you to decide for yourself. Never use lossy compression if you want the best sound (Jplay doesn’t play lossy compressed files)
People have reported a burn-in period & improvements in the JKDAC32 with the major changes happening in the first 48 hours or week of use.


Normal Operation:
The JKDAC32 works completely off-grid from its 2 internal A123 Lithium Nano Ferrous Phosphate (LiFePO4) batteries so it can be used anywhere.
A battery charger is internal to the JKDAC32 box. This will require an external 9V or 12V DC power supply with 2.1mm plug (center pin positive). Details will be found here . This is best plugged in at all times as it will charge the batteries when the JKDAC32 is turned off.
When charging hard the LED light will turn red & faint green when topping up or finished. The charger automatically stops charging once the batteries are full. To explain a bit more - the battery charger works initially in constant current (CC) mode, if needed i.e it keeps the current fixed at 2 amps & varies the voltage as needed. It's at this stage that the LED is red. As the voltage approaches the set voltage it changes to constant voltage (CV) mode & varies the current - the LED shines green at this stage
There is about 18 hours continuous playtime from fully charged batteries.
The LED doesn’t decrease in brightness as the batteries are used – it stays bright as the batteries continue to output around 3.3V until discharged. When discharged the output voltage is about 2.7V – 3V so the LED will still light but there will be no sound or spluttering sound form the JKDAC32.
Full top-up recharging will take about 4-5 hours whereas normal top-up recharging takes about an hour.
See next page for a discussion of jitter & how to evaluate the sonic effects of reduced jitter

Warnings:
PLEASE don’t plug any other power supply into the aluminium box other than the specified one.
PLEASE don’t run the batteries to depletion – it shortens their life (20 years expected) & may damage them!
The build inside the box is tight & cannot be opened without breaking it electrically.
Opening the box voids its warranty.


A note about the sound of low jitter:

This is a quotation from Bob Katz, well known recording & audio mastering engineer posted herehttp://www.digido.com/audio-faq/j/jitter-better-sound.html

After an engineer learns to identify the sound of signal-correlated jitter, then you can move on to recognizing the more subtle forms of jitter and finally, can be more prepared to subjectively judge whether one source sounds better than another.

Here are some audible symptoms of jitter that allow us to determine that one source sounds "better" than another with a reasonable degree of scientific backing:

It is well known that jitter degrades stereo image, separation, depth, ambience, dynamic range.

Therefore, when during a listening comparison, comparing source A versus source B (and both have already been proved to be identical bitwise):

The source which exhibits greater stereo ambience and depth is the "better" one.

The source which exhibits more apparent dynamic range is the "better" one.

The source which is less edgy on the high end (most obvious sonic signature of signal correlated jitter) is the "better" one.

And a reply:
The better one, and it is better, is also easier to listen to. . . less fatiguing. I would also add to this that the low end just "feels" bigger and more solid. This is perhaps a psychoacoustic affect more than a measurable one. It may be that the combination of a less edgy high end and greater depth and width makes the bass seem better.
All of this makes sense if thought of in terms of timing (that is what we're talking about isn't it ;-]). With minimal jitter nothing is smeared, a note and all its harmonics line up, the sound is more liquid (a term probably from the "audiophile" crowd but one which accurately describes the sound none the less), and images within the soundstage are clearly defined. 

[tony]

Hi John, Great to see you going ahead with this I would like to register my interest in the JKDAC32. Rgds Tony

[jkeny]

JKDAC32 List:
1 Tony - received 11th Feb
2 Mick - received 26th Feb

[jkeny]

JKDAC List:

[jkeny]

JKMK3 List:

[jkeny]

I've started 3 lists of names - one for each device & will keep these lists updated as well as I can
I will add a name to the relevant device list when someone posts their interest.
I will record against their name the date when they receive the device
I will delete them from the list when they have posted their brief synopsis of impressions.

Tony, I have added your name. Please PM me your address & phone no.
I hope to begin to send these out next week

[jkeny]

Ivor has kindly offered his off-license as a very convenient drop-off & pick-up point for the exchange of these devices in Dublin. Much appreciated, Ivor, maybe you could give some instructions on location of your premises & times of opening?

[tony]

Hi John, I cant find the original message advising what option to take when ripping cds to disk. Should I use flac or wma? If my memory is correct its flac but?

[Fran]

yes, either flac or else wav