replacing 2SK78 fet in a Yamaha preamp

[unclejed613]

As I said a long time back - junk the stupid idea, and build a decent preamp in the same box with the same facilities.

that depends on if you only want a functional preamp, or if you plan to some day sell it to a collector... Yamaha audio equipment seems to be very collectible, especially anything before 1990 vintage.

 

[Nigel Goodwin]

that depends on if you only want a functional preamp, or if you plan to some day sell it to a collector... Yamaha audio equipment seems to be very collectible, especially anything before 1990 vintage.

Never really been a great name in audio, nice musical instruments and motorbikes though

 

[vtech]

Hi everyone,
Sorry to bring this old thread back but I'm facing the exact same situation here.
I'm having the hardest time finding a proper match for 2SK78C transistor that fried on a Yamaha C1 pre amp.
The one shown on the attached picture.
Did you end up finding a good replacement for this one?
Thank you for any help you could bring!!
Greetings from France!!

I happened to be involved with Yamaha Audio at the time ...
2SK78/2SJ24 were made by Yamaha utilizing the SVJ technology and were exclusive to some of the their Home Audio products during the "low noise" contest era.
There were couple of packages(T092, T05) along with A/B/C suffixes which mainly changed the power dissipation.

 

[unclejed613]

I happened to be involved with Yamaha Audio at the time ...
2SK78/2SJ24 were made by Yamaha utilizing the SVJ technology and were exclusive to some of the their Home Audio products during the "low noise" contest era.
There were couple of packages(T092, T05) along with A/B/C suffixes which mainly changed the power dissipation.
View attachment 133982View attachment 133983

what do you think about the idea of replacing those devices with depletion mode MOSFETs?