IBM vacuum tubes

Joshua Rice Rice43 at
Mon Jun 15 09:03:13 CDT 2020

Hard to say, without the modules they came from. 

As far as my (limited) understanding of vacuum tube logic goes, double triodes were very common for implementing basic boolean logic functions. Therefore, most IBM vacuum tube computers and data processing machines would have hundreds/thousands of similar dual-triode tubes making up the logic. 

Basically, they could be out of any vacuum tube machine made by IBM. IBM 600 and IBM 700 series machines being the most likely.

> On Jun 15, 2020, at 2:51 PM, Guy N. via cctalk <cctalk at> wrote:
> While going through my assortment of old vacuum tubes looking for audio
> treasures, I found a handful of IBM branded ones.  Mostly 5965, but
> there's one 5963 mixed in.
> These are dual triodes with the same pinout as common small-signal audio
> tubes such as 12AX7/7025/ECC83, but characteristics closer to 12AT7 or
> 12AU7.  My RCA Receiving Tube Manual says they're designed to withstand
> being held in cutoff for long periods of time, and mentions digital
> applications.
> Anyone know what kind of IBM machine these would have been used in?

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