Sorry to be tardy - I just found this thread.
I started modding my 2805 and 2905 nearly two years ago. First I messed about with caps and resistors - metallized poly all sounded the same; the big difference came with using more film and foil. When I got up to 70uF film and foil plus 150uF metallized, the sound was dramatically improved. Duelund resistors were better than Mills WW.
The big breakthrough came with changing the step-up transformers to the Vanderveen design manufactured by Plitron. I used the 75:1. To my ears, the best sound came with using NO signal shaping other than an input resistor (as Vanderveen suggests). Best resistor in my setup was obtained by using nichrome wire as speaker cables - I have a monoblock behind each speaker, so short wires are feasible. Each of the two wires is a bit more than one ohm.
Best improvement of all was making my own low power monoblocks with low voltage rails. With this setup, it is physically impossible for the amps to punch a harmful spike into the speakers - so I could safely eliminate all of the protection circuitry. Sound is quite magical.
I hope that you are experienced with ELSs, because they can kill the unwary in several ways. Please be careful. All the best!
I started modding my 2805 and 2905 nearly two years ago. First I messed about with caps and resistors - metallized poly all sounded the same; the big difference came with using more film and foil. When I got up to 70uF film and foil plus 150uF metallized, the sound was dramatically improved. Duelund resistors were better than Mills WW.
The big breakthrough came with changing the step-up transformers to the Vanderveen design manufactured by Plitron. I used the 75:1. To my ears, the best sound came with using NO signal shaping other than an input resistor (as Vanderveen suggests). Best resistor in my setup was obtained by using nichrome wire as speaker cables - I have a monoblock behind each speaker, so short wires are feasible. Each of the two wires is a bit more than one ohm.
Best improvement of all was making my own low power monoblocks with low voltage rails. With this setup, it is physically impossible for the amps to punch a harmful spike into the speakers - so I could safely eliminate all of the protection circuitry. Sound is quite magical.
I hope that you are experienced with ELSs, because they can kill the unwary in several ways. Please be careful. All the best!