Preamp to compete with Kyocera C-910

I've managed to assemble a set of rare Kyocera 910 separates. These were Kyocera's stab at the high-end in the early 1980's, superb build quality, excellent sonics, top-notch engineering etc. (In 1984, the B-910 amp retailed for $2000, the C-910 preamp retailed for $1200)

My C-910 has been completely recapped and refurbished--but the problem is, there are certain proprietary components that are simply unobtanium, and I fear that one of these has gone south. The result is an occasional crackling and hissing in the right channel.

The thing is, when it's no sending out a crackly signal, the thing sounds superb. Both the previous owner and the tech who worked on it--Randy, aka Ezekial--said it was amongst the best they'd ever heard.

I'm flirting with the idea or simply getting something modern, but another part of me doesn't want to part with stuff so rare.

So my question is, to those few who may have experience with this gear, what do I need to be looking at to find comparable performance in a pre-amp?