I just noticed the valves in my new Croft are 12SN7 not 6SN7 as I assumed. A I understand it's designed for a 6 I put the RCA 6s in in place of the GECs that came with it. Firstly I noticed more bass, but I thought there was a but less control over it. Also after an hour, the top was hot whereas it ran cool with the 12s. So I'm wondering if I'm taking a risk doing this, given I understand the Super Micro A was designed to use 6SN7s. Is it normal to run hot with pre tubes, it felt more like a power amp heat wise.

I'm probably going to put the 12s back in, but are there risks in running 12s in a pre designed to take 6s? From the heat issue I'm assuming not, and given I prefer the sound it's a no brainer otherwise.

Sent from my BLN-L21 using Tapatalk