[Vinnie R.]

All,

I purchased an Astell & Kern AK100 last month.  It is a high-resolution digital audio player.  It plays
files up to 24-bit /192kHz.  Here is the website of the player:

http://www.astellnkern.com/

It's a really nice design, with features like an WM8740 dac, mini-Toslink digital output (that also outputs up to 24/192k),
built-in 32GB FLASH and two mirco-SD card slots to fit another 128GB into, 12-hour battery life, charges with any USB
charger (5V), drag-in-drop of music files, supports WAV, FLAC, AIFF, ALAC, AAC, etc. 

There was a lot of controversy on Headfi.com about the 22-ohm output impedance (the thread is 140 pages and still growing!) - as this is quite high for headphones, especially low-impedance IEMs: http://www.head-fi.org/t/630288/the-new-iriver-ak100-a-high-end-dap

Last month we began offering a modification called the RWAK100.  There are the details of the modification that we posted on Facebook:

I have received many emails asking if Red Wine AUdio could modify the AK100 at the same price as the iMod ($250 + shipping). Due to the overwhelming interest, the answer is - YES!

And we are selling brand new RWAK100 modded units for $895 + shipping. Until we update our website, please email us to place your order.

Details of the RWAK100

We bypass the 22-ohm resistors in the output stage, and hard-wire (via Cardas copper litz solid core wire) from the output stage FETs directly to the pins of the headphone output jack. Besides bypassing the 22 output resistors, this also provides the shortest, cleanest path from the output stage to the headphone jack - also bypassing the tiny circuit board traces, and the header that connects the main board to the smaller headphone jack board. It's essentially a direct connection from output stage to the headphone jack. Output impedance is now under 1 ohm...

This is by far the most natural sounding DAP that I have heard so far! It is also a very portable size (smaller and lighter than an iPod) and has a super-quiet (NO background noise to be heard), built-in headphone amp that drives all IEMs with ease, as well as most full-sized headphones to adequate volume levels. There are layers and layers of details and nuances that this little DAP unravels!

Also - the RWAK100 is one fine sounding source component to either feed your portable headphone amp (set the volume to max and you'll have a line out - as the volume control sets the output level of the Wolfson d/a and is not in the signal path), or use the mini-Toslink output to feed up to 24/192 files directly to your dac. It blows away the mini-toslink out of the Macbook Pro - and sounds really sweet into our Bellina Pro dac!

All in all - I'm very proud of the AK100 and the output stage modification and just how good this unit sounds compared to many other portable sources, dacs, and all-in-one players. This is true reference quality, and iRiver/A&K deserves a lot of credit for their fine design (the internal layout is 1st rate).

Note - I have NO affiliation with iRiver or A&K. The modification will void your warranty, but I warranty the RWAK100 modification for as long as you own it, and for any service you need not related to the RWAK100 mod (e.g. replace battery, LCD, etc) - I will offer you quick servicing (price is based on parts and labor).





Pricing

Send in your AK100 for the RWAK100 modification - $250 + shipping.

Purchase a brand new RWAK100 from us - $895 + shipping (while we have them in stock - email to confirm).

Shipping:  $15 inside USA, $55 outside USA

Paypal to: vinnie@redwineaudio.com


Purchase a stock AK100 here:  http://www.aloaudio.com/ak100


Best regards,

Vinnie

[TONEPUB]

Hey Vinnie:

I've got a stock one, want to do a comparison review?

[Vinnie R.]

ABSOLUTELY! 

I'll send a RWAK100 to you with your Black Lighting....

Thanks,

Vinnie

[srb]

and two mirco-SD card slots to fit another 128GB into

Vinnie,

Astell & Kern say the SD slots accept cards of 32GB max - have you performed some modification to extend the maximum to 64GB?

Steve

[Vinnie R.]

Vinnie,

Astell & Kern say the SD slots accept cards of 32GB max - have you performed some modification to extend the maximum to 64GB?

Steve

Hi Steve,

It has been tested by AK100 owners that it works fine with 64GB micro SD. 

You must format the 64GB microSD card to FAT32 to see the whole 64GB. With Mac use your disk utility for that.



Best regards,

Vinnie

[Bonzite51]

Hi Vinnie,

Just your view on this mini-Toslink digital output (that also outputs up to 24/192k) please?
It is standard optical transmitter inside AK100?

Regards,
Janis

[Vinnie R.]

Hi Vinnie,

Just your view on this mini-Toslink digital output (that also outputs up to 24/192k) please?
It is standard optical transmitter inside AK100?

Regards,
Janis

Hi Janis,

I am very impressed with the mini-Toslink output of the AK100.  It outputs at the resolution that matches exactly with
the file being played.  I've tested it with our Bellina Pro dac using a glass fiber optic cable and it is very impressive.  Even when
playing Redbook files, it can easily compete with high end CD transports. 

I don't know what kind of optical transmitter is inside the AK100, other than the fact that it is built into the headphone output jack (so
it requires mini-Toslink to Toslink cable).

All the best,

Vinnie

[roscoeiii]

Vinnie,

As best I can tell, the RWA mod is just for the analog output stage? Is there any benefit to your modded units if this is intended primarily as a transport?

[Vinnie R.]

Vinnie,

As best I can tell, the RWA mod is just for the analog output stage? Is there any benefit to your modded units if this is intended primarily as a transport?

Hi roscoeiii,

You are correct - the mod is just for the headphone output. 

Best regards,

Vinnie

[Vinnie R.]

We finally have more RWAK100s in stock!

Get 'em while they're hot because the orders are coming in quick! 

[roibm]

Hey Vinnie,

could you please describe what all the changes you made do, and what their downside is (beside the obvious warranty voiding)?
I have second thoughts one can just bypass the output resistor in series and all is fine, without any secondary effects. Wouldn't it have been wiser to bypass it with a lower resistance, say 4R7 for a total of 3R9?

What other circuitry is bypassed beside the respective resistor? A picture would also be nice, I doubt it will hurt your business, quite the contrary.

Also, I got word of a AK100 follower, which is supposed to have a "much lower" impedance and dual mono DAC chips, got anything on it that you can share?

[Vinnie R.]

Hi roibm,

Welcome to the RWA forum!

The RWAK100 mod bypasses the 22-ohm resistors on the output.  By eliminating them, the player delivers
a flatter frequency response with lower impedance headphones and IEMs.  To see the problem with the stock
player, refer to this link:

http://www.head-fi.org/t/630288/the-new-iriver-ak100-a-high-end-dap/735#post_8937333

I have second thoughts one can just bypass the output resistor in series and all is fine, without any secondary effects. Wouldn't it have been wiser to bypass it with a lower resistance, say 4R7 for a total of 3R9?

I have extensively tested this without the resistor (even shorting the output to confirm the output stage does not fail), and it is proven to
work best - definitely the lower the output impedance, the better. 

What other circuitry is bypassed beside the respective resistor?

We bypass the traces in the MB that lead to a header that connects to a smaller board on top that has the headphone output jack.  So we hard-wire from the output FETs directly to the headphone jack pins.  We make the connection as short and clean as possible.

Also, I got word of a AK100 follower, which is supposed to have a "much lower" impedance and dual mono DAC chips, got anything on it that you can share?

At CES, iRiver did not mention that this is in the works.  The only new versions of the AK100 that I have seen are the "limited edition" ones in the silver and gold enclosures (I think they sold in Japan and Hong Kong).  iRiver will be at the NY Audio Show in mid-April (which we'll be exhibiting at - so we'll see if they have any additional info).  Being that the AK100 is quite new and still gaining momentum and reviews, I can't see them changing it anytime soon.  They're not Apple  But there are always going to be rumors.  I don't believe it until I see it!

Best regards,

Vinnie

[krisstack]

This is great news.
 
I've yet to find a portable solution that I'm completely satisfied with.  I have an iPod Classic/Cypher Labs AlgoRhythm Solo combination that I use with either UE Reference Monitors and a ALO Rx MkII or JH Audio JA3/JH16.  Of the two, I prefer the JH Audio.  While this setup sounds nice to me for redbook audio (ripped ALAC files), I find I'm getting more and more hi-rez music that I want to play, even when I'm out and about.  While I can always resample the files, as long as I'm in a peaceful location, I think I want to listen to the hi-rez.  I also thought having half of the bulk would be appealing.

So I decided about a year ago to buy an iBasso DX100.  This has not been a great experience.  The first unit was DOA, but iBasso quickly sent a replacement.  However, in the year I have been using it, I've been frustrated with the bugs.  Sometimes it works great, but other days the player app seems to crash frequently; it doesn't seem to be related to what file it is playing.  Some days it will mount as a drive so you can move music on and off, other days it won't.  Maybe it doesn't like working with OSX.  It does seem to work better when I use Windows 7.  But my biggest frustration are the drops out when playing 192/24 files.  I will say that when it works, the sound is good, though not quite as good in my opinion as the iPod stack.  It does sound better with a pair of Etymotic 4S headphones I have, than the Etymotic 4S sounds with iPod/Solo/Rx combo.  I think that classical music with the Ety/DX100 combo is better than any of the headphones I've tried with the iPod stack.  Some people have touted that it can drive a greater variety of headphones without and external amp, but this is not a feature I care about- when using a portable setup, I only want to use an IEM.

I heard the AK100 at the recent NY Audio show, and it seemed like a nice unit from my limited audition.  They were demonstrating it with some LCD2 headphones, and there were many people looking to try it, so I didn't switch to using my IEM's.  But with the mods that Vinnie has made, I'm sure it will be an improvement over the DX100 - so sign me up.

[Vinnie R.]

Hi Kris,

Your RWAK100 will ship today - it's really the best sounding DAP on the market right now, and it is the perfect size and super-quiet
background noise so a great match with all IEMs (but it plays my LCD3s, HD650s, and others just fine as well!).

Keep us posted! 

Vinnie

[Vinnie R.]

All,

We have RWAK100s back in stock and orders placed can ship this week. 

Cheers!

Vinnie

[Diegoniax]

Hi Steve,

It has been tested by AK100 owners that it works fine with 64GB micro SD. 

You must format the 64GB microSD card to FAT32 to see the whole 64GB. With Mac use your disk utility for that.



Best regards,

Vinnie

OR use fat32format-guiformat to format to FAT 32 in win 7 or 8

[nParbat]

I have read that the volume knob on the a k100 feels cheap and inconveniently sticks out. Are there any thoughts on a non /s mod that addresses this and retains the use of the internal amplifier?
Cheers,
Scott

[Vinnie R.]

I have read that the volume knob on the a k100 feels cheap and inconveniently sticks out. Are there any thoughts on a non /s mod that addresses this and retains the use of the internal amplifier?
Cheers,
Scott

Hi Scott,

The AK100/AK120 knob controls a rotary encoder (it's a digital volume control - not an analog volume pot), so it doesn't feel like a standard volume control.  It's also smaller than a typical headphone amp knob.  But I have yet to hear of anyone who has an AK100 or AK120 whose knob has broken.  It's actually very strong.

Even if I were to try to install a different volume control, there is really no room inside to fit it.  So there is not much that can be done with regards to that.  We get rid of it for the S and B mods (which convert the player into a dedicated source), but this requires a headphone amplifier.

If you want to retain the internal amp, I don't see how it could be possible to relocate the volume knob and/or use an analog volume pot due to the lack of space in there.

All the best,

Vinnie

[Brad]

Off-topic:
Vinnie - any comments on DSD sound quality through the AK120?

[Vinnie R.]

Off-topic:
Vinnie - any comments on DSD sound quality through the AK120?

Hi Brad,

It sounds just as good as the high-res PCM does on the AK120, IMO