It has a Weber copper cap rectifier and I really like the punchy sound enough that I'll keep it in there. The person I bought it from played it loud through a 4x12 loaded with greenbacks and it had a sound reminiscent of an older, 4-hole Marshall. Takes pedals like a champ and is easily the most beautiful sounding amp I have ever heard, let alone had as my own! Now, I think I need to find an attenuator. This amp is LOUD.