Since I performed the 6V6 UL optimization investigation (documented
here and
here) the most common question I've been getting is
"Are you going to redesign the Lacewood Amp?". Well, I think It's time to get going on this project. The amp will look identical above the plate, but underneath, things will be different.
The optimization point for which I'm shooting is about Vk ≈ 18v, Vp ≈ 275v, and Po ≈ 4.3W / Channel. This will mean that I can't use my favorite old style shouldered 6V6GT tubes any more, but they will get used in another amp. Now this level of bias voltage means that the driver is not sensitive enough, so it gets a new design as well. I am also going to shift the volume control to the input to reduce end to end distortion at less than full volume. The result may make the amp a little less warm, but if it's warmth I'm craving, I'll put my 4S out front with a 12AU7 (or even a 12AT7 if I really want warmth). Here is my first cut at the schematic directly out of my notebook.
Attachment:
6V6 Lacewood rewire schematic (s).jpg
Note: Ignore the currents and bias voltage on the power stage, this was when I was still considering limiting Vp to 250V.Of course, the power supply will be changing as well. I want to get the awesome soundstage I'm been seeing in my recent amps, so I'll be removing the 5H choke and inserting two 1H chokes to split the power to each channel. This should greatly increase the channel separation and really bring out the detail in the soundstage.
Unfortunately, I won't get much done this week, but this project is going to be a major focus over the Christmas break. It should be fun.