Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: bnwitt on February 22, 2018, 03:44:51 am

Title: Ever Seen one of these Flip Flops?
Post by: bnwitt on February 22, 2018, 03:44:51 am

Quite some time ago I inherited a couple of cardboard boxes full of old electronic stuff from someone who thought I might have some use for it.  I'm still going through the stuff (most of which is junk) but I came across an 8 pin to 9 pin adapter device made by Electronic Engineering Co. of California which is an adapter that converts an 8 pin socket to a 9 pin tube.  It is labeled a Flip Flop, ZA 8336, 12AU7-5963 and I have put some photos of it in the Dropbox folder at the link below.  I'm just wondering if anyone has ever seen one of these or know what it was used for.  It had a very nice 12AX7 RCA black plate tube in it which I still have in my stock  Any ideas?


https://www.dropbox.com/sh/kza6ndrxvvo0c1o/AAAsG45HzSOB3Q8ZPW3UdXaHa?dl=0

Title: Re: Ever Seen one of these Flip Flops?
Post by: sluckey on February 22, 2018, 06:53:14 am

It's a flip/flop (bistable multivibrator) module with set and reset inputs and 1 and 0 outputs. They were common during the early 'digital' days before transistors had taken over. It's not just an adapter. There is an actual bistable multivibrator circuit inside the can.

Title: Re: Ever Seen one of these Flip Flops?
Post by: shooter on February 22, 2018, 10:18:49 am

here's where you can find "where it went"  start with the Univac 1 or 2 :icon_biggrin:

Fortunate for me I started with the 1218 version, smoking computer!!!  to date one of the finest computers I've worked on  :think1:

Title: Re: Ever Seen one of these Flip Flops?
Post by: bnwitt on February 22, 2018, 02:03:06 pm

Wow!  There must have been thousands of these made.  I wonder what the pin out was?  I found a youtube video on the memory assembly:

https://www.youtube.com/watch?v=kignGE77l_I (https://www.youtube.com/watch?v=kignGE77l_I)

Title: Re: Ever Seen one of these Flip Flops?
Post by: PRR on February 22, 2018, 08:16:48 pm

> They were common during the early 'digital' days before transistors

They are still common: a modern CPU has millions of flops. A flop is a 1-bit memory, handy for holding part of the problem you are chewing on. In BJT form:
https://www.electronics-tutorials.ws/waveforms/tim17a.gif
Today MOSFET structures can be printed smaller.

Ah-- here are bi-stable flip-flops done with tubes, from the Eccles and Jordan patent 1918.
(https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Eccles-Jordan_trigger_circuit_flip-flip_drawings.png/300px-Eccles-Jordan_trigger_circuit_flip-flip_drawings.png)

As you see: two triodes and some other stuff. The parts in your can are the other stuff. The 12AU7 is the two triodes to make it flip and flop.

Title: Re: Ever Seen one of these Flip Flops?
Post by: bnwitt on February 23, 2018, 11:23:53 am

Thanks PRR