Preamp to pair with vintage PS Audio 100 delta?

I am tempted to scout for a matching vintage PS audio preamp to interface with my recapped 100 delta, and have started to look for 4 series (e.g. 4.5, 4.6 etc.) and 5 series units on the bay, but am wondering if this is the best choice compared to some of the newer tube offerings? I run phono and digital, so the active/passive feature of the vintage PS Audio units looks appealing. Any suggestions or feedback on the different PS Audio units would be greatly appreciated, as well as thoughts on some of the newer reasonable tube/DAC units. I use the 100 delta to drive a pair of PSB Stratus Goldi full range floor standing speakers.