Topic: Will Nak 300 mics tolerate 12V?

[notlance]

Since LR44 cells can be bought for about $0.10 each, I was thinking of using a stack of them to power my Nak 300s.  A stack of 8 cells work out to be about the correct height, but that results in a 12V battery.  Will 12V harm the mics?  I suspect not, but I thought I'd ask before I do the smoke test.

[runonce]

Nak 300s use 2SK118, which is rated up to 50V.

I believe you are refering to the FET?

[SmokinJoe]

I think I read somewhere that 12V is considered an absolute max.  I wouldn't push it.

I would go with a 6pack= 9V and some sort of metal slug to take up the space.  Or I suppose you could take one battery and flip it around, thereby dropping the voltage of the 8-stack down to 9V.

[notlance]

Thanks for the help.

Since the LR44s would rattle around inside the mic, I'll have to make some kind of PVC holder for the batteries anyway, so I guess I could plug one end with a 12 mm bolt.  Then I could make the holder work with 6 or 7 cells.  Sound like a nice Winter afternoon project.

[Roger Gustavsson]

I have used up to 15V without any problem. Chris Church have reported that anything beyond 7V or so will not be needed. You can use two 3.7V/1200mAh Lithium cells in series. They will last about 1000 hours.
Nakamichi-guru Stephen Sank, told that he used up to 15V if the JFET was a 2SK35 and up to 28V for 2SK118. He also replaced the series capacitor with a higher voltage rated one. You can also cut down the microphone housing and use three 3V CR1632 in series. 

Roger