[kukkurovaca]

You just need to install in your own mint tin or 3D printed case.

I'm not that handy with DIY stuff -- would I just be able to to have the case printed by a 3d printing service and then screw it together?

 

[xrk971]

Dbaldock,
Cool! Please respond in the DIYA thread to show interest.

 

[xrk971]

I am looking at option to provide the 3D printed case for a nominal cost circa $30 - depending on how many people interested. There are many onlOne 3D printing services that will print for you if you provide a file. We may be able to leverage more units to bring costs down.

 

[xrk971]

3D printed case version with 5000 mAhr battery.

 

[xrk971]

New thread on DIYA to discuss technical aspects of the new HPA with battery management system. Amp will be called the Hakuin HPA.

Block diagram of LiPo and wall-plug power management system:

https://www.diyaudio.com/forums/headphone-systems/345851-hakuin-se-class-hp-amp.html

 

[M3NTAL]

Big fan of how the Pocket Class A sounded with my IEM's and looking forward to the Hakuin. Any chance to keep us updated over here also? I'm not a DIY guy and not a member of that forum. It makes it hard to follow that thread. Thank you!

 

[xrk971]

Testing of the Hakuin is going well. I have had a lot of help from member Itsallinmyhead on DIYA. He built several prototypes and found an issue with the battery fuel gauge meter. Fortunately, the rest of the PSU works well: the smart charger, the DC-DC step up, the ultra low noise LDO regulator, and the solid state relay (SSR) anti turn on thump delay works as well. Now for the sound, I have built that myself and initial tests have revealed it to be a superb sounding amp. Much more highly resolved than almost any other amp I have heard. Despite being only 2 transistors- the sound is superb. Great bass dynamics well beyond its size and power rating.

We are about to implement the fix to the fuel gauge system (LEDs).

Here are some photos of the prototype being tested with an external PSU. Itsallinmyhead built the PSU and I’ll share those photos later.

if you look at the photos, you will notice some multi legged IC’s. Those are not opamps but dual low RDson MOSFETs used as SSR’s and their 4 pin opto-coupled controllers. Audio signal is still opamp free.

 

[xrk971]

Here is a re-post if member Itsallinmyhead’s listening impressions in case you can’t access DIYA.

Link to DIYA review

Scuse Me While I Kiss The Sky
I had the opportunity to A/B the PCA and Hakuin for a few hours while I was waiing for the Hakuin’s battery to drain down, so I could check the “fuel gauge” circuit.

Background
As I’ve said many times on these forums, I’m no reviewer. I don’t know how to apply all the “audiophile terms”, and I find them generally meaningless when others use them. I think I have tin ears vs. golden. But… I do love music, I listen to music almost constantly throughout every day, and I know what I like. With that said, my music doesn’t need to be “audiophile quality”. I listen to a lot of recordings that many would consider crap, and the vast majority of my music comes piped from a Sonos through my ceiling speakers. However, I’ve assembled a few decent loudspeaker systems over the years, and I own some purportedly decent headphones, IEMs, amps, DACs etc. So, if you’ll trust the opinion of a self-proclaimed music lover with a terrible case of GAS (Gear Acquisition Syndrome) – read on.

Intro
Man… I wish I had these amps 40 years or so ago when I would sit with a pair of headphones trying to write down lyrics. As an older guy trying to learn to play a bit of guitar, I know I can hear nuances and riffs – particularly in recordings multitracked with the same guitar over top of itself. If I could sing even a little, I’d use them to pick a singer out of a harmony to match. They are both exceptional amps IMO

Summary / Conclusion
So how do they differ?

In a few words. The Hakuin provides a bit more effortless detail and maybe a slight change in what I perceive as localization in and around my head.

In more words. What I love about both amps, is their ease of providing the music. I never want to take off my headphones. I never get that fatigue, headaches, or even pain associated with some rigs I’ve tried. I’ve used various PCAs for 100s of hours while traveling. There is NO “shouty” behavior anywhere… anytime. With the Hakuin, I feel like I get that same delivery, but with just a shade more detail and no added fatigue or harshness. I've heard some rigs where I can hear details exceptionally well, but they make me want to tear my ears off after 20 or 30 minutes, or I get a headache. These don't do that to me.

The only other difference I think I perceive is that with the one pair of IEMs I used, it seems to move a bit more of the far left and right… well … further left and right. Almost seems like edges are “stronger” with whatever is center stage in the “center of the head” becoming no louder, but more easily discernable. It’s no more “forward” in the middle of the perceived soundstage, but the parts of the recording that are right inside the old noggin’ (like lyrics) are more easily picked clean. There’s no degradation of what’s on the edges “in the ears and just outside”, but that potentially wee bit more separation allows whatever is front and center to be very easily heard and understood.

I still want to try it with other headphones and give it more time.

My Guesses

• If you have a PCA and love it, you’ll probably want a Hakuin.
• If you don’t have a PCA, and need a portable amp – Once they’re out… If you get your hands on one, you'll probably want to keep it.

----------------------------------
Notes -

Both of these were built with my amateur hands. I have no idea how they measure, but I’d give it a 90%+ shot that they perform as XRK971 intended.

The PCA has the Panasonic caps and Silmic cap changes and is running at the “standard” bias. I used sequential bugs from the reel in the build, but this one did not have super carefully hand selected/matched parts.

The Hakuin is a prototype. I don’t know whether there will be further tweaks. As with the PCA, I used sequential parts from the reel for the JFETs and BJTs. I did not go to the trouble of matching to 5 significant digits. The Hakuin does use some pretty sweet parts if you’re into that sort of thing.

Source – iPhone 6 running Qobuz. Streamed vs. Downloaded. All tracks at 16/44 or higher. HP output set to one click from max.

IEMs – Beyerdynamic Xelento

I level matched the amps using a few sections of songs and white noise by ear to the best of my ability.

I sometimes listened to 10-30s of a song before swapping amps, and sometimes I listened to a few songs. Sometimes I went back and forth a few times within a song and repeated sections. Sometimes I listened to the full song, many times I did not.

--------------------

Songs and general focus areas – I just picked some random albums and a few songs I know pretty well. It’s what I wanted to listen to this morning, plus a few things I like to use when listening for certain things. Nothing specific. I don’t “critically listen”. I don’t know how. As you’ll see – I have some eclectic? tastes…

Still Crazy After All These Years – Live in Central Park
Homeward Bound - Live in Central Park

Harmony, Guitar, Crowd Noise, and Ambience

Homeless – Graceland

Sense of space, vocals – the vocal sections and individual voices

Diamonds on the Soles of Her Shoes – Graceland

LSBM Vocals and Sibilance

Nobody Knows You When You’re Down and Out – Unplugged
Hey Hey – Unplugged

Guitar work, Bass

Midnight Rider – A Decade of Hits
Guitar work

Helplessly Hoping – So Far
Woodstock – So Far
Find the Cost of Freedom – So Far

Harmony and discernment of individual voices, Guitar work

Sexual Healing – Midnight Love

Bass, Vocals

What’s Going On – What’s Going On

Intro conversation, Vocals

Ain’t No Mountain High Enough – United
You’re All I Need to Get By – You’re All I Need

Vocals – Tammi’s specifically. Shrill or not in places?

Fade Into You – So Tonight that I Might See

Lyrics… ooooooh that voice.

Fade Into You – Playing Favorites

Lyrics… ooooooh her voice too.

Whiskey Lullaby - A Hundred Miles or More

Vocals... Emotion

Molly Bawn - A Hundred Miles or More

Intro and Vocals.. Emotion

Can’t Find My Way Home – Blind Faith
Everything…

Angry Chair – Unplugged
Over Now - Unplugged

Bass, Kick Drum, Clear Lyrics, Guitars

If I Had $1,000,000 – Gordon

Sibilance, Naturalness of voices / conversation, fiddle and accordion

One Week – Stunt

Lyrics

The Chain – Rumours

Mick’s drumming. Harmonies.

Silver Spring – The Dance

Stevie’s Voice… Piano

Flight of the Cosmic Hippo

Bass, but really all of it… C’Mon!

After 2nd cup… Mainly Used Just Because I Still Needed Music No Notes
What Is and Should Never Be - II
Going to California – IV (Runes) Whatever you want to call it
Dragula – Dragula
Thunder Kiss ’65 – La Sexorcisto – Devil Music Vol. 1
Ænima - Ænima
46 and 2 – Ænima
Jerk Off – Opiate
Opiate – Opiate
46 and 2 – O’Keefe Music Foundation - YouTube

Last song was from YouTube vs. Qobuz

Pic of "High-Tech A/B Rig". Notice the fancy cables

 

[DBaldock9]

I'm interested in how the Hakuin sounds, when driven by a Radsone ES100 or a FiiO BTR5.

 

[xrk971]

I am using an SMSL Sanskrit 10 which has a nice AK4490 DAC - one of the better ones out their IMO. Perhaps similar in signature to the Radstone's AK4375A. Sources included mix of FLAC and WAV files from either Jriver or Amazon HD streaming. You definitely can hear the difference with the Hakuin.

 

[gikigill]

I am using an SMSL Sanskrit 10 which has a nice AK4490 DAC - one of the better ones out their IMO. Perhaps similar in signature to the Radstone's AK4375A. Sources included mix of FLAC and WAV files from either Jriver or Amazon HD streaming. You definitely can hear the difference with the Hakuin.

Long time between drinks Viet, looking forward to the Hakuin now. The original Low and Hi Impedance PCA are still going strong.

 

[xrk971]

Hi Gill,
Yes it has been ages and 30 amps later. The Hakuin is a really nice amp. I still haven’t had time to finished the pocket Hakuin with LiPo and DCDC and charging system through. Just not enough interest from folks. I have a module version of it for the Yarra as a preamp and that works very well too.
Cheers,
xrk971

 

[gikigill]

Do you have any working prototypes for sale. I am definitely interested in the Hakuin.

 

[SDBiotek]

I'd be interested in a finished pocket Hakuin myself.

 

[xrk971]

Maybe I should have asked over here if folks were interested. Although this thread has been here for a while and nothing until today. I don’t have any pocket Hakuin prototypes fully working yet. The amp part works but the charge indicator LED fuel gauge still needs work.