Any one tried to use subminiature for input tubes?

[DJNUBZ]

Just wondering if anyone has tried this before. Seeing as they were some of the last tubes designed and were supposedly well made I figgure they may be an untaped resourse.

[nuvistor]

Do you have any? The types with glass envelopes and wire pins aren't all that common. 6111 is mu=20, 6112 is mu=70. I have some used 6111s that I haven't fired up yet.

If you mean nuvistors, like 6CW4 mu=65, 7586 mu=35, I used to find these at hamfests before eBay, not so much any more. They are rather microphonic, ring at about 10kHz.

For low-level input, good 12AX7 or 12AY7 are by and large not microphonic, low flicker noise, well suited to phono input. Nuvistors are probably OK for line level but I'm wary of their microphony

[Eli Duttman]

FWIW, the 6DS4, with its low noise and high gain, has me thinking about phono stage service. Putting a drop of silicone or acrylic caulking on top of the envelope might tame the microphonics.

[RE 604]

Hello ,
suminiature tubes ? Yes , look here :



and here is the complete projekt :

http://www.ak-tubes.de/Vorverstaerke...ube_preamp.htm

and another little amp is here :

http://www.roehrentechnik.de/html/kolibri.html

Regards , Alex .

[Tubes4e4]

Hi Alex,

Originally posted by RE 604
Hello ,
suminiature tubes ? Yes , look here :

K³\/\/L wiring / parts placement technique

That reminds me I have a few TFK 5676 in the drawer

Tom

[SY]

Those are the Tektronix ceramic terminal strips? If so, how did you mount them? The ones I have are secured to the original Tek chassis by a little plastic o-ring which does not seem to be removable without destroying it.

[EC8010]

Originally posted by RE 604
Yes , look here:

That's a lovely construction.

[RE 604]

Hello Sy ,
it it very easy to remove this Tektronix terminals , they are only pressed in their plastic holders . You need only a screwdriver to pull them "carefully" out . I had no problems to do this .

@EC8010
Thank you for your nice comment for my little preamp , I had great fun , building this , but the pcb version is easier to build and works also very well .
Regards , Alex .

[SY]

Were you able to re-use the little plastic o-rings?

[wa2ise]

Submini's work well. They are really not different than regular tubes, just smaller and cute looking

Look at my web page using subminis in radios and in CD players as input tubes

Only ones I've seen as microphonic were filament DHT types. Indirectly heated subminis are designed to take a beating (like in rockets and warheads and such). Well, not literally but they are designed for high G forces.