Hello Lakecat!
Do you still use the Mac 2205 for the AR-LST, I had read over the foreign speakers forums some one upgraded the AMP for LST from the MAC 2205 to Mac 2500, the Guy said the mac 2500 is better than the 2205 when using for AR-LST, ME myself had owned the LST, in the past I had used the Mcintosh MC 275, a huge modern Mcintosh 402 weigh 120 pounds, 400 watts stereo 800 watts mono and fisher C-500 for the LST, I don't understand how come the HUGE Mac 402 , hooked up to the AR-LST, the bass is not tight as the Fisher C-500 tube receiver... so after using 3 amps for a while , result: 1. Fisher C-500, 2. Mcintosh mc 275 tube, 3. Mcintosh 402 ...so I temporary end up use the Fisher 500 C for my AR-LST,,, I am still looking for the Mac 2205 and the Phase Linear 700 series II amp that Frankmarsi recommended the best AMP for the LST....but not find both of it yet.