Does anyone recognise this component (Teladi K120 mic)

Hi!

Does anyone recognise the small glass tube component on the bottom left? It's a small tube with two electrodes, one shaped like a cup.



From its context it should do the job of a voltage regulator or zener diode.

Thanks!

z50

Hi,



  I think it'll be a neon. iirc, there is one in the meter circuit in an LA2a . . . .



    What mic is, anyway?



    Kindest regards,



      ANdyP

strangeandbouncy said:

I think it'll be a neon.

Click to expand...

Most likely candidate. And hence, basically a zener diode. Someone on the forum, maybe SSLTech mentioned that neons can be "hideous" sources of noise, and that a zener replacement is always an improvement.

Could well be - Thanks.

Kingston said:

can be "hideous" sources of noise, and that a zener replacement is always an improvement.

Click to expand...

That figures - certainly something here is a hideous source of noise!

strangeandbouncy said:

    What mic is, anyway?

Click to expand...

Teladi K120, with a quite different circuit to the one next to it. Notably the output cap would be in the PSU so you have many volts DC on the audio out. The other has the cap in the mic. Could cause trouble!

Well, they certainly look amazing! How big is the capsule? . . . .and how do they sound?


    lucky man . . .



    ANdyP

strangeandbouncy said:

Well, they certainly look amazing! How big is the capsule? . . . .and how do they sound?

Click to expand...

Capsule is about 3/4 inch across, so 'medium', and it looks to be nickel rather than gold coated. Sadly they're both unusuably noisy in their current condition. Both capsules look well so I'm trying to work out the best way to make them usable and still be sympathetic to the original.

Nice!

I like the ECC82. Are these plate-out then?

Yup - uses both sides of the tube to give two stages, both stages are plate-out. Got one of these about a year ago and the second last week.

First one is like this....



But the component values are different, mic no.2 has the neon and there's something funny going on around the capsule polarisation.

I'll draw up a schemo for the new one and see what we can learn.

PS I posted some info in this earlier thread but forgot - there are a couple of good comments there.
http://www.groupdiy.com/index.php?topic=29657.0