18Watt.com

“That’s not 18 Watts.”
Uhh, but it is …err, eighteen Watts?
Two days ago I became obsessed with ECL86 tubes - the ones used in the Marshall model 1930 Popular. So over the weekend I focused on nothing but this new design. It’s a 2-tube, single ended, class A, 18 Watt amp to be built in a 5F1 chassis in a tweed 1x10 combo with a Celestion G10 Gold speaker. I’ve spec’d it with MM iron but it can be built with Heyboer, Edcor, Hammond or whatever. My new little “Turbochamp”. Now, finding the time to actually build it…

Sounds pretty cool

Looking through the RCA tube manual, it appears that this will be around 8 or 9 Watts output power, not 18 Watts. I was mistakenly originally referring to the plate dissipation rather than the power output.

ECL86s have a hifi cachet so are a bit pricy. I have used PCL86s which have 13v heaters which I ran at 12v for convenience. They cost a third as much a few years ago.
Dd

Update, the schem & layout I posted are missing a filter cap, here are the updated dox and some pix of the circuit on a stock 5F1 eyeletboard.

It’s fitting nicely into a stock 5F1 chassis, with just a few slight mods.

Here's how to build it using EL84s and a 12AX7,
sorry about the low-rez images: