Rerurn to Romy the Cat's Site

I sent an email to Brian asking... also about how far down in frequency their largest mumetal core could go.

I see why you want those tap options now - essentially you want to be able to load down the 6e5p but still use all the secondary sections. There may be some frequency response variations in the ultrasonic range by playing the tap game, but it shouldn't make all that much difference to what you hear.

A while ago, prices were of the order of GBP 100 each for the mumetal OPTs. Assuming they haven't changed much, that's about $400 plus carriage/import duty etc for the pair.

For the HF channel transformer; well, air core would be big, with very high capacitances. You really want a very low Z tube to drive an aircore.

However, something has occurred to me. The RAAL already has a matching transformer on a small core to which you are cap-coupling; I wonder if Aleks might wind something with a much higher turns ratio and cap couple directly to the 6E5p anode on the S2 amp. Fly in the ointment: he would need to ensure the insulation between windings could handle 400+v. Where the RAAL takes over, the inductance of the S2 should be high enough so the 6E5 isn't loaded down too much.

Having said that, do you know what the DCR of the ribbon element is? I have a pair of 90:1 aircores in London designed for driving raw ribbons direct from a SET... there would be some rolloff at 20kHz, but would well be worth trying if I can get hold of them in the next few months...

Rerurn to Romy the Cat's Site