2A3 SETs with Edcor Iron

[kmaier]

I started another side project recently, a 2A3 SET based on an old classic schematic similar to the Fi series of 45/2A3 SETs (with a slight change). I wanted to try some Edcor iron so I picked some of their current lineup and ordered it... then went for coffee.

Ah, after the iron arrived I did the mechanical layout and opted for two separate chassis; one for the power supply and one of the amplifier, so 4 chassis mirror-matched.

Here's a couple pics of the final mechanical assembly. I used one of the newer 1590DE series Hammond die-cast series... metric dimensions and black powder coat. They survived drilling to 3/8-inch and Greenlee punches to 1-1/8" without issue.... and just manage to support the 25W SE OPT from Edcor... it's a monster.

Wiring is next

Regards, KM

[Pano]

Cool setup!

[Ryssen]

+1

[kmaier]

Wired up one of the supplies yesterday. It works... then again, not much to it.

Regards, KM

[kmaier]

Have wired up the second power supply and one of the amplifier chassis. Both supplies perform as expected... the amplifier circuit (basically what the Fi SET uses) is somewhat underwhelming. Output power is light (barely 3 watts before clipping), THD is pretty high and frequency response is down a few dB at 20KHz. The default biasing on the 6SF5 input/driver is ~ 0.45ma which is pretty low. I'll re-bias the amp a bit and see if I can get an acceptable level of performance but there will be limits.

Regards, KM