All the Lundahl transformers have a gap, including the PP version which as far as I know is the same as the LL1660/5mA version. The different suffixes in mA refer to what the gap is suited for. A 25mA gap will be bigger than a 5mA gap. But as the capacity for current goes up the induction comes down. Which is why you need to chose exactly the one you need for optimum performance. Thankfully the 4P1L has a lowish plate resistance so the induction isn't as critical as with the 26 for instance, so you can use a 25mA gap which is the current the 4P1L needs. The 26 is better off with a 5mA gap to keep the inductance high.
Dave, of course, knows of the 4P1L's existence but I do not think he has had extensive experience with it. I have asked him.
Thought it would be interesting if you or mogliaa had some "dream" specs.
I am sure DS will come up with something.
Take care,
Another 4P1L is born, still needs a few tweaks before i button it up but it's 90% done. Big thank you to KevinC and Ale for your help and inspiration!
Layout is based around the Siberian Gen 3 schematic with Kevin's shunt regular supply, Rod Coleman regulators running filament bias, and CCS plate loads with a capacitor coupled output instead of some iron. Its big and hot and sounds fantastic, just like the F4 amp its driving
Thanks all!
Layout is based around the Siberian Gen 3 schematic with Kevin's shunt regular supply, Rod Coleman regulators running filament bias, and CCS plate loads with a capacitor coupled output instead of some iron. Its big and hot and sounds fantastic, just like the F4 amp its driving
Thanks all!
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