The power supply is responsible for much of your amps sonic signature. If you send it back to CJ for these updates, I can assure you that it will sound nothing like it did. My advice is to have it restored to spec. Buy a new amp if you want the modern "teflon cap" sound.
Opinions on vintage cj amps and Teflon cap mods
I'm seeking opinions on having a vintage amp modified/updated. While I'm enjoying my conrad johnson Premier V as is, I can hear some significant differences when compared to some of the more modern amps I've heard. In my opinion, the sound I'm getting from my system is too soft, particularly the leading edge of notes and the upper base/lower mids. Decay, air, ambiance and overall musicality are great IMO. conrad johnson is offering modifications to the Premier 4&5 amplifiers which would include a new power supply and Teflon capacitors. What's crucial to me, is that I'm looking to improve the amplifiers performance, not just change it. The cj person I talked with said they've modified a couple of the Premier 4s with "smashing success". Thanks in advance for your experiences and opinions.