My preamp experiences:
Tried a Realistic SA-2001 amp in preamp mode into a Stereo 70 - mediocre, but better than the SA-2001 as an integrated. Never buy one.
Then, found an Audionics BT-2 preamp in a pile at a pawn shop, my first real, high-end preamp. It was good, and I wish I still had it...but I traded it in for a...
Yee preamp, which I paid too much for, and nicknamed "Dull Thud." Never buy one.
After the Yee mistake, I had a Music Reference RM-5 mkIII with a custom outboard power supply. It was very nice, had it quite a while, but it was not the best I ever owned. Sold it on eBay.
In time, I got a Meridian 205 pre - it was well-made and competent, but too neutral, and not euphonic. Sold it, but I still love shoe-box amps.
After that, I made do for a while, plugging whatever source (everything I was using at the time had a variable output) into this five-watt, Magnavox, console pull, single-ended, EL-84 amp. It worked very well - sources as preamps. I miss that amp.
Then, I found cheap at a flea market, a Phase Linear 2000 mkII. Loved it, but foolishly traded it off for a Nak receiver. Stoopid!
Currently, I'm using my Arcam Delta 60 as a passive pre, and I only power it up for phono, which is excellent. You'll have to pry my cold, dead fingers off this one!