"K118" Semiconductor - HELP?

[GlidingDutchman]

Hi there

I need some info on a semi-conductor simply marked as "K118" in a tube pre-amplifier (feeding one half of a 12AX7 tube - two units for the single tube).

Is this some kind of regulator? or what?

I have searched and Googled but couldnt find any concrete info.

D

[AndrewT]

could it be a 2sk118?

[GlidingDutchman]

Originally posted by AndrewT
could it be a 2sk118?

Could be - I am not sure. It is a tiny unit with three pins like a TO-92 package but squared off at the top.

D

[scott wurcer]

That's the standard marking for the 2SK118 look on top for the "color" grade, it will be a single letter.

[GlidingDutchman]

Under the simple "K118" there is also printed in very small font "0 46"

D

[scott wurcer]

For us that might mean year 2000 week 46 date code. Pretty easy to test non-destuctively with a voltmeter.

[GlidingDutchman]

I did download the 2SK118 data sheet and it seems like it. Certainly looks the same.

Now what do you think it would function as? Buffer amplifier or voltage regulator?

D

[analog_sa]

Originally posted by GlidingDutchman
Buffer amplifier or voltage regulator?

Most probably neither. CCS.

[GlidingDutchman]

Originally posted by analog_sa

Most probably neither. CCS.

Okay... whatta CCS? Engris pleas...

D

[analog_sa]

Constant current source. Active load for the the 12AX7. IDSS @5.6mA matches quite nicely the expected plate current of 1-2mA.

You can verify this from your boards - there should be a resistor between gate and source and the fet should be the plate load of the tube. Well, just a guess.