Blue Circle BC3 vs BC21.1

I think some of the advantages the BC3 might have are dual volume pots and an external power supply. I'm using the older BC21 which uses 6SN7 tubes. Used Galateas sell for under $2000 and Despinas even cheaper.

Do both units have the stock tubes? That would make for a more objective test. Do you own the BC22 mkI or mkII? It never occured to me that the BC21.1 and BC3 Despina might have different output impedances, but your experience indicates that might be the case. With most solid state amps I've partnered my BC21 with, the volume knob is set to around 8 o'clock. There have been a few exceptions where I needed to crank it past 9 o'clock to get the same perceived volume.

It should be fun test progression for however long your comparison lasts. Please keep us updated. I'll add that changing to WWII era NOS 6SN7s in my 1st gen BC21 resulted in monstrous improvements. In your case, I believe it would be 6922 tubes for both preamps.

Have fun!