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6SL7 Double triode


6SL7 Double triode

Post by RobJKMannering » Thu Sep 01, 2011 4:19 pm

Sorry Mods if this is in the wrong section, Could not find anything for specific radio components.
I would like to attempt a one valve receiver from an American book using an 6SL7 double triode. I have found this is a AF freq. triode and wonder what I could use that would be easier to aqquire.
It is only a simple TRF so would any double triode be okay as long as heater voltage and HT are suitable?

[mod]Have moved this to "In the Workshop" which seems to be the best place for discussions about components, valves etc. Perhaps we should make this a bit clearer. Apologies for accidentally locking the thread during the move. Now fixed. ppppenguin [/mod]

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Post by Michael Watterson » Thu Sep 01, 2011 4:56 pm

Pretty much, yes any correctly wired valve.

HT isn't critical actually, as long as you increase or decrease Anode resistor.

The bias may need adjusted with a different valve. The data sheet will show. But likely not critical.

It's really a two valve radio though!

A pair of 70c Russian Rod Pentodes will even work in Triode circuits at low voltage HT if you tie G2 and G3 to Anode. A 1j24b takes 12mA @ 1.3V filament. At 9V to 22V HT I've used the 1j18b as a triode by ignoring or earthing Anode and using G2 as the Anode.

My Hergé radio is really a one valve radio with a 3 valve audio amp added:)

An ECC82 will work.

None of these designs are very critical. The most you need to do is change value of cathode (bias) and/or anode (gain/load) resistors to improve performance.

Have you a link to the schematic?

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Post by rob t » Thu Sep 01, 2011 5:08 pm

nearest (easy to get) would be ecc83 but as ivon said almost any double triode audio valve would do
rob t


Post by RobJKMannering » Thu Sep 01, 2011 5:11 pm

Thanks, the circuit is in a book I borrowed.
Having read your posts, I realise your fondness of Russian valves, the price of which may lead me to experimentation.
I have an ECC82 so will try that first. Of course it is a two valve set, just in one bottle!

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Post by Michael Watterson » Thu Sep 01, 2011 5:20 pm

I'm a Cheapskate.

Must be the Scottish chequebook I inherited. No perforations.

Also I'm lazy. I have some regular valves I've been meaning to do stuff with. But I have to get a Baking tin from Tesco (€2.50) and put holes for the valve sockets. Get some tag strips. etc.

It's very handy testing valve designs on an IC breadboard and then making them on Veroboard!

I feel the need for a DM70 now as it's a wire ended "magic eye". :)

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