[gikigill]

Happy to wait and can you give me a price please as I'm happy to put in a deposit of 20%.

 

[gikigill]

Is the LED gauge necessary if a blinking light will do?

 

[M3NTAL]

I'd be interested in a 120v wall powered version. A dedicated amp for hi-end balanced armature users. We are all stuck using an iFi adapter or reducing digital volume in the source.

 

[xrk971]

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 you can make it work as a plank amp too.

btw, in case you don’t know what anYarra is - interchangeable amp cores. The Hakuin would be a small daughterboard that sits on the main board.
Hakuin cores on a plank amp:

Yarra preamp:

 

[iFi audio]

We are all stuck using an iFi adapter

iEMatch saved many setups. It ain't that bad

 

[pure5152]

I've been an avid lover of my PCA for a couple years now and just discovered the Hakuin! It looks freaking fantastic. I saw the last update posted was on the DIYA forums with an updated picture of the proto. Given it's been half a year, any new updates about it? :O I'm very interested in it given performance seems to be a step up over the PCA.

 

[Peter19500]

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 bias current and this seems to give the sound an immediacy and naturalness that’s close to LIVE sound. It’s an experiment that is turning out superb. It’s what I am listening to at present as my main portable amp.

https://www.diyaudio.com/forums/gro...-pocket-class-headamp-gb-189.html#post5750411

Revised schematic:

This is the predicted FFT for 1.4Vpp into 55ohm headphones (THD is only 0.05%):

Test amp with new resistors and only 117uA of bias current through the input JFET:

I bought the circuit board and transistors from you on Etsy. It works very well. Could I make this modification? I only use these headphones: Gjallarhorn GH50 Jm.
Driver Graphene-coated multilayered composite

Driver Unit 50 mm

Frequency Response
10-50000 Hz

Sensitivities 116 dB

Impedance 33 Ohm

Maximum Input Power 250mW

Thank you for your response.