Blue Hawaii BJT Build thread

[starcat]

Thread seems to be dead, all builders left 🙂

[mwl168]

The original design of Blue Hawaii uses 2SK170 BL grade which has the IDSS grade in the same range of LSK389B.

Double check the data sheet to confirm.

2SK170/LSK389 are JFET so using either 10K or 50K volume pot should be fine. 10K pot may be more ideal if your source can drive it.

[mwl168]

Switched from Megatron to the Blue Hawaii this morning. Different sound signature but equally as satisfying. 

This one is not the BJT version but the one that uses 2SK216/2SJ79 with cascoded CCS and adjustable plate current. 

 

[audiostar]

Very interesting, someone here is calling the BH an "Orpheus clone"... @kevin gilmore

[kevin gilmore]

that person is a moron. the orpheus has 3 capacitor coupled stages. the BH is completely dc coupled.

[chinsettawong]

Maybe he was referring to the DIY headphones he was testing.

[spritzer]

Yeah, those are the one Milos was working on. 

[simmconn]

TL; DR: I’ve wanted to build a Blue Hawaii ever since I read about it on head-wize. I finally got around building a mini BH-BJT packed into a small enclosure like a can of sardines. Many small tweaks were done in attempt to reach the measured performance of the original Blue Hawaii. The details of the journey are recorded here.

Many thanks to Dr. Kevin Gilmore for designing this legendary project. Thanks to Kerry, JimL, Joamat and many others for making it such a fun journey.

KGBH1.pdf

[JoaMat]

Jolly good work!

Thank you for the excellent PDF document. Lots of interesting stuff there.

[Kerry]

^This.  

[MLA]

On 1/26/2023 at 9:20 AM, simmconn said:

Many small tweaks were done in attempt to reach the measured performance of the original Blue Hawaii.

Working on a BH at the moment, and given what you found regarding Cob for 2690; do you think it would be worthwhile to use TTC004b instead, or is the difference too small? I guess you may have checked it but discarded it as an option?  

[Helium]

On 5/3/2024 at 9:57 AM, MLA said:

Working on a BH at the moment, and given what you found regarding Cob for 2690; do you think it would be worthwhile to use TTC004b instead, or is the difference too small? I guess you may have checked it but discarded it as an option?  

Seems that KSA1220AYS may also be replaced with TTA004B,Q? The latter also seems better.