Strange Valve Circuit - Redrawn for Clarity

Sorry. My mistake.

Have you? You are broken mentally so it wouldn't show.

Reply to
John S
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Just look it up online. Type in 6AC7 and see what comes up.

Reply to
John S

I don't really need to do that. I know what the 6AC7 is/was. I was just trying to clear up the confusion over how many grids are shown on the original drawing.

Reply to
Pimpom

I will help you. There are *three*.

Reply to
John S

Read my post above. I said "The original drawing shows 3 grids." I even explained how the poorly drawn symbol could have been mistaken as having four grids.

Reply to
Pimpom

I saw that but was counting the cathode!

NT

Reply to
tabbypurr

Yet you're the one ragging on someone else for a mistake that you're making right in your bitch. Amazing. But such stupidity is expected from you.

Reply to
krw

This is what I was thinking Bill. Having equal length leads "60 inches or less" on the input and output implies to me that feedback may have been intended. The circuit would thus oscillate and effectively become a transmitter.

This assumption seems to be supported by the very high gain and (deliberate?) lack of bypass.

Unfortunately, I have no further details on the device itself.

But I do have a similar circuit, also using four 6AC7's, from another source which I will redraw and post on a new thread in a day or two.

Robert Miller

Reply to
Robert Miller

The circuit as drawn will do nothing. There's no cathode connection to ground. Assuming anything (ground at the bottom of the 200 ohm resistors ?) with this odd circuit may lead one down the garden path ...

Ed

Reply to
ehsjr

The redraw is not accurate - in the original drawing the cathode resistors all connect to the supply transformer centre-tap (0V) via the

100 milliamp-ammeter.

piglet

Reply to
Piglet

50 years ago we wouldn't even be having this discussion. It just goes to show how very seldom these devices arise in designs nowadays.
Reply to
Cursitor Doom

AFAICR, the cathode does count. So if this tube has 3 grids, it's a

*pentode*. We don't bother about heaters.
Reply to
Cursitor Doom

Some illegible (and possibly vital) text from the original is also not clarified or even included in the redraw.

Reply to
Cursitor Doom

And how slow the Internet was in 1967. ;)

Cheers

Phil "O brave new world that has such people in't" Hobbs

Reply to
pcdhobbs

I think what tabbypurr meant was that he mistook the cathode for another grid.

Reply to
Pimpom

Hehe! You're a funny guy, Phil. :)

Reply to
Cursitor Doom

An understandable mistake. Could have happened to *any* blind person.

Reply to
Cursitor Doom

Thanks for the comments. That's the return for the 6.3V across pins 2 and 7. I left it out for simplicity. I should have mentioned that. Sorry.

Robert Miller

Reply to
Robert Miller

Fine. But four grids does not make a PENTAgrid .

Reply to
John S

I admit I made a mistake (essentially a typographical error). My response was not to correct a typo, but to correct a mistake in understanding.

Are you on the rag?

Reply to
John S

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