Hey Gewehr98...

[280plus]

Must be the dual knob model...

[Gewehr98]

AND, a 30 year old RCA 12AX7 driving the gain in the preamp :-)


only bummer is: it's the only one i have.... when it goes out, it's back to new manufactured tubes :-(

Not so.

There are LOTS of NOS (New Old Stock) tubes out there to be had, in their original boxes, even.

The 12AX7 was/is fairly common.  I'll bet I could find a replacement NOS RCA variant that shipped the same year as yours without too much trouble.  In fact, I have one sitting in front of me right now, sans box.

[seeker_two]

Must be the dual knob model...

Best kind when you're "tuning in Tokyo"....

[Gewehr98]

Scratch that idea.

That Eimac is a serious RF output tube. 

The filament runs at all of 7.5 volts, but draws between 20 and 22 AMPS!

That tube's best left for its intended purposes, or kept looking good on a shelf somewhere.

As for NOS RCA 12AX7 preamp tubes, look here:

http://cgi.ebay.com/Pair-of-RCA-Boxed-12AX7-Tubes-Tested-Strong-Matched_W0QQitemZ200255205272QQcmdZViewItem?hash=item200255205272&_trkparms=72%3A1207%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

[K Frame]

"The filament runs at all of 7.5 volts, but draws between 20 and 22 AMPS!"

Holy CRAP!

[Nick1911]

Scratch that idea.

That Eimac is a serious RF output tube. 

The filament runs at all of 7.5 volts, but draws between 20 and 22 AMPS!

That tube's best left for its intended purposes, or kept looking good on a shelf somewhere.

As for NOS RCA 12AX7 preamp tubes, look here:

http://cgi.ebay.com/Pair-of-RCA-Boxed-12AX7-Tubes-Tested-Strong-Matched_W0QQitemZ200255205272QQcmdZViewItem?hash=item200255205272&_trkparms=72%3A1207%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

Wow; bet the power output on that sucker would be up there.  Hook it up to an oscillator and start jamming certain parts of the radio spectrum for half the US!