Having searched internet with no luck makes me think the idea of a PP (or CT) plate-choke is bad. Found a small one at Lundahl:LL1668 but nothing else.
Thought of it to be used for PP-Parafeed or ESL DD. Of course you could use a standard PP-output with terminated secondary but this does not feel optimal.
Someone who knows where the catch is?
Thought of it to be used for PP-Parafeed or ESL DD. Of course you could use a standard PP-output with terminated secondary but this does not feel optimal.
Someone who knows where the catch is?
No catch, they're just not in big demand, so you don't see them as catalog items very often. The MagneQuest's EXO-173 is based on the Peerless 17173 which was used in the Altec 1570 (load for PP cathode followers.) I know that Jack at Electraprint has wound PP plate chokes on a custom basis and has learned a few tricks.
If you really feel like experimenting you can combine two SE plate chokes so that they share a common magnetic circuit. Remove the 'I' part of the core of each and butt the 'E' parts together. Ideally you would net 2x increase in inductance, but I wouldn't expect quite that much. It might not be an ideal solution, but it might work better than separate plate chokes. It's one of those things you'd just have to try for yourself and let your ears decide.
-- Dave
If you really feel like experimenting you can combine two SE plate chokes so that they share a common magnetic circuit. Remove the 'I' part of the core of each and butt the 'E' parts together. Ideally you would net 2x increase in inductance, but I wouldn't expect quite that much. It might not be an ideal solution, but it might work better than separate plate chokes. It's one of those things you'd just have to try for yourself and let your ears decide.
-- Dave
Dave Cigna said:
Hi Dave,
Small world!!! I contacted Jack yesterday and he offered to custom wind a pair at a very reasonable price. He really seems to know what he is talking about.
This is the amp they are supposed to work in:
www.revintage.se/ScriptEL34T.pdf
Hey, if you guys are working with Jack, then you have nothing to worry about; he already knows what works and what doesn't. But, for anyone that's thinking about making these things themselves I will offer one small piece of advice: don't go nuts with interleaving. None is required and listening tests have shown that none sounds best. Just wind the two coils on a dual bay bobbin in opposite directions. Simple and guaranteed to work.
The only reason I bring it up is that I have had conversations with some people planning PP chokes that were thinking that a ton of interleaving would make it better. Some even planned bifilar winding. Forget about it! Bifilar will KILL the thing. Jack would probably refuse to wind it for you.
Lars, that looks like a very cool amp to drive ESL's. It shouldn't be too hard to make a very good PP choke for you application.
-- Dave
The only reason I bring it up is that I have had conversations with some people planning PP chokes that were thinking that a ton of interleaving would make it better. Some even planned bifilar winding. Forget about it! Bifilar will KILL the thing. Jack would probably refuse to wind it for you.
Lars, that looks like a very cool amp to drive ESL's. It shouldn't be too hard to make a very good PP choke for you application.
-- Dave
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