Re-tubing my ARC reference 1 preamp

What type of tube are talking about? 6922?

For "warm" versions of the 6922 type you might want to consider some NOS Mullards, probably the warmest of the lot, next in warmth would be Amperex. I think the Siemens and Telefunken tend to be the most neutral and linear. I agree about the 6H23 which you can get from Upscale Audio, they did sound better to me the current production Sovtek, and they are not too expensive.

Slates, I think you have a good starting point. The 6H23s are only $15, so you can try and decide.

You will get warmth with those Mullards. Good sources for NOS in my experience have been Brent Jesse and Vintage Tube Services. Hardes part is getting closely matched and balanced pairs, but these guys seems to do a good job.

I bought a matched pair of Amperex White Label and they sound great in my amp. Since I don't have my own tube amp measuring equipment, I have no idea whether or not the tubes measure as he says, but he has a reputation for being fanatical about measurment and quality. You probaly need to hear from someone that has measuring equipment to know that what Andy says he is selling measures as he says. All I know is they tubes came as described and sounded very good in my amp.