From 1955 until 1965 EL81 was used in PA and early hifi amplifiers (from Philips Germany if I'm right). A push pull pair produces 20W of audio power.
20W yes, in class B, I believe most of us here do not call that "HiFi"
The Philips AG9006 was an early OTL, used on 1200 ohm loudspeakers. Very rare these days and rather unaffordable then
Yes, looks like a PL81 (or maybe EL81). PL81 and PY81 were very common in European black&white TV sets. PY82 is a supply rectifier, with no top cap.
Probably rare in the US is the Brimar 6BS7, a miniature low noise pentode with a top cap for the grid. Probably a variant of the 6BR7.
Probably rare in the US is the Brimar 6BS7, a miniature low noise pentode with a top cap for the grid. Probably a variant of the 6BR7.
Yes, looks like a PL81 (or maybe EL81). PL81 and PY81 were very common in European black&white TV sets. PY82 is a supply rectifier, with no top cap.
Probably rare in the US is the Brimar 6BS7, a miniature low noise pentode with a top cap for the grid. Probably a variant of the 6BR7.
Philips, it seems were a little confused on the subject of top-cap for the PY82; the line drawing shows the anode connection at the top of the valve, whilst the base diagram shows anode at pin 9!
I had a Marconi valve voltmeter that was fitted with 6BS7 (or 6BS8?) with grid top caps. I converted my Quad IIs to run 6BR7s as suggested by Chris Beeching. Very satisfactory.
7N7
The data sheet you linked to shows it quite clearly as a single-ended valve. The only thing on top is the glass sealoff pip.
Yes that's right - in the representation of the envelope, but above there is a line drawing showing the anode connection at the top.
7N7
Yes that's right - in the representation of the envelope, but above there is a line drawing showing the anode connection at the top.
7N7
? Are you referring to the tube schematic symbol? That's as standard a symbol as you can find; it doesn't imply a top cap.
? Are you referring to the tube schematic symbol? That's as standard a symbol as you can find; it doesn't imply a top cap.
OK my mistake, thanks, a bit over-wrought I think today
7N7
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