Anonymous wrote:Hi Shannon,
I have noticed that you have referenced in a few post here that you have been experimenting with a 6B4G version of the eiclone.
I would love to have more details or progress of this variant, will it become a reality offered to the public in the near future?
Thanks
Norris Wilson
Hi Norris,
Earlier this year I built a couple prototypes on the Ike board. One was a cathode biased version using a Hammond 270HX and Z565 (sound familiar?). I was using the open bracket 4H Hammond as input choke, with a small tuning input cap to give me a B+ around 320V. The neat thing with this arrangement, is that with a different 'tuning cap' we can use a tube rectifier like the 5AR4. The rest of the unit was basically like the Ike, except tweaks everywhere for the negative feedback and DHT filaments.
The neat thing now is that I've put a spot for the National Semi LM334 on the board, which makes a fixed bias version feasible. The grid resistors on the 2A3/6B4 are supposed to be 50K in fixed bias arrangements (though I think you can get away with 100K per some of the old schematics I've seen). The CCS allows us to get adequate drive in fixed bias, which is difficult otherwise, at least with the Ike topology.
I have a couple chassis in the shop right now (err, I'll get those drawings to you asap, Bottlehead). I'm hoping to have these be my official pair to use for releasing the finalized cathode biased design. Realistically, my goal is by the end of '04. I've got a couple projects almost done around here I must finish first. But anyone dying to tackle this project now, just drop me a line. I'll give some pointers.
Shannon