Hi people,
I've got hold of a decent sized bunch of MHLD6, an old duo-diode/triode valve from the 30's. Specs are pretty hard to find for them so I thought why not trace them out myself, I've never done this before but it seems to have worked, see attached.
I'm trying to ascertain the utility of these things, as I can probably get a lot more. They are all ex-government stock, I suspect ex PMG or Victorian Railways.
mu is about 23
rp is about 7.3k
gm is about 3000 umhos
No idea of max plate dissipation but the structure is a bit under twice the size of a 6SN7.
The curves don't look bad to me, but I'm not an expert and I haven't run any loadlines as I don't have a printer at the moment.
What do other people reckon?
EDIT: I've only bothered about the triode section, obviously.
I've got hold of a decent sized bunch of MHLD6, an old duo-diode/triode valve from the 30's. Specs are pretty hard to find for them so I thought why not trace them out myself, I've never done this before but it seems to have worked, see attached.
I'm trying to ascertain the utility of these things, as I can probably get a lot more. They are all ex-government stock, I suspect ex PMG or Victorian Railways.
mu is about 23
rp is about 7.3k
gm is about 3000 umhos
No idea of max plate dissipation but the structure is a bit under twice the size of a 6SN7.
The curves don't look bad to me, but I'm not an expert and I haven't run any loadlines as I don't have a printer at the moment.
What do other people reckon?
EDIT: I've only bothered about the triode section, obviously.
That was my thought also, I was hoping it wasn't just wishful thinking on my part. It was introduced at around the same time as the 6J5 so that makes some sense I suppose.
Cheers Andreas, those pages are where I got the pinout etc. It seems to be impossible to get any more info than that though. Hence tracing it out myself.
This valve seems to have dropped out of sight very early. Neither the 1949 nor 1966 versions of the Wireless World / Iliffe Radio Valve Data manuals list it and the Mullard manual (1955 ish) gives no suggested alternative which is most unusual. Still, your measurements and the similarity to a DL63 should enable you to get some use out of them.
Barry
Barry
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