A wall powered Hakuin? That’s actually available as a daughterboard module on the Yarra preamp/headphone amp main board. https://www.diyaudio.com/forums/group-buys/334457-yarra-preamplifier-hpa-melbourne-db-buy-124.html It just needs a 24v single rail supply. Provide inputs and outputs and...

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.

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...

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.

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

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...

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

3D printed case version with 5000 mAhr battery.

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.

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

Hi Folks, I haven’t been here for a while but thought you all might be interested in a new project brewing over on DIYA. It’s going to be a new PCA Mk II. This time fully assembled and tested and ready to run (RTR) all SMT design. You just need to install in your own mint tin or 3D printed...

Here’s the new Muscle Amp - uses eight OPA1622 in parallel. Can drive speakers even down to 4ohms. About 10w into 8ohms. Tested T 47ohms and listening with 50ohm HE400i. Fantastic dynamics. Zero noise or background. Powered with 25va 15v trafo through a cap multiplier for low noise power source...

New Balanced Drive 2 Transistor SE Class A Headphone Amp with beautiful harmonic profile and ability to drive 50ohm cans. https://www.diyaudio.com/forums/headphone-systems/338656-balanced-drive-2-transistor-se-class-headphone-amp.html Measured FFT for 2Vpp itno 49ohms:

Here’s a new spin on this amp. Using an ultra low 117uA bias current in the JFET (via new DC setpoint resistors), the sound is sweeter (lower third harmonic relative to second) and lower overall THD, and more dynamic through higher gain. It seems that the input signal had to control a much lower...

I was wondering when you were going to build the balanced DCA’s. Do you have 6 boards?