I have a Audio Innovations First 2A3 tube amp. Slightly faulty at the moment and will require service. I use this with Border Patrol PSU. I got a TK2050 from Hifimediy recently to keep me going until I got the First going again. Wow! This thing is superb - I use SLA batteries and quality stepped attenuator. Question is - do I stick with TK , get First sorted and then run in biamp mode ?? Say, the TK on bass , with tubes on midrange/high ?? Is it worth the hassle and expense. Shall I get another TK for £25 and run biamp with that?? Any thoughts welcome !