Quote from: EBK on December 02, 2022, 07:16:25 PM
Interesting. Glad you got it sorted out.
Yes, me too! I thought I was losing it because I couldn't find anything physically wrong with the build.
I did some more experimenting and tried a couple of late '90's Yugoslavian Ei brand and an unknown brand of old stock tube that has "Britain 12AX7A/ECC83" stamped on it. Both are longer plate tubes similar to the old German Telefunkens. Huge volume boost with these.
There's something about how the circuit is designed that favors certain tube types. The Russian one that is commonly available and worked well is an EHX 12AX7EH that has the short dual parallel plates. I settled on the old stock "Britain" tube because it provided the most output; about 20%-ish more than the EHX. The Ei tubes were good as well, but I liked the sound of the Britain tube better.
I'm curious to find out what tubes are used in the actual B.K Butler pedals. I wonder if anyone in the forum has one that they could open and find out?