Re: Tube tester plug-in for 576 curve tracer project

Dave Casey
 

Those common pinouts are already done for you in the RCA Receiving Tube
Manual; see the section titled "Terminal Diagrams for Receiving Tubes".
Each unique pinout is given a name and you can find all commonly pinned
tubes listed under that name. For example, the popular 12AX7 has terminal
diagram "9A". Looking under "9A" there is a long list of tubes (including
redundancies such as ECC83 and 7025), but also any other noval tube with
the same pinout like 12AY7, 12AZ7, 6AU7, etc. There are a LOT of different
7-pin, octal, and noval configurations.

Dave Casey

On Sun, Apr 2, 2017 at 5:17 PM, edbreya@... [TekScopes] <
TekScopes@...> wrote:



Thanks Dennis, I know what you mean about common pinouts. That's a good
listing - I could have used info like many times that for finding
substitutes to try out. Please do keep building on these listings.

It can certainly simplify things in a limited-arrangement system. In my
switched scheme I made assumptions about always using the same heater pins,
the most typical K pins for grounding, etc - I even tried to arrange the
different socket interconnects so that say, a 6AU6 fitted to the 7-pin
would use the same pentode lines of the 6U8 in the 9-pin. But my system
rapidly got out of hand complexity-wise, when considering a few more
different ones. An inspiration came about when I looked at the 0B2, which
shorts a bunch of pins internally. That I think was the moment I realized
that it's very important to also consider what's not connected, and that
jumper lead programming was much more flexible (PTP) than switching, as
long as you can minimize the number, and figure out what to do with them
all within each setup.

As I tinkered with different possible arrangements, it has evolved into
what I think is a pretty cool system, so I had to talk about it and see
what people think. The downside is that the spaghetti is on the outside,
but the upside is that it's pretty easy to implement the circuits, and it
can be set up for lots of different tubes (almost anything that will fit
one of the sockets) that I may encounter in maintenance or experimenting,
that I couldn't have foreseen. It's also easy to program - I can just look
at the pinout in the datasheet and plug it all in accordingly. Of course,
setting up the right heater and screen voltage etc is necessary, but that
goes with any system.

Ed

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