Best Used Tube Preamp (under $750)?


I need a used tube preamp under $750, and am having trouble deciding which. I have yet to listen to these, but the price has determined these suggestions. Audio Research LS7, Sunfire Classic Tube Preamp, Rogue Audio 66, and that's all I've found so far. If you have an opinion of one of these, or a unit I haven't mentioned, PLEASE post a follow-up. Thanks all.
zorathustra
Counterpoint SA1000, SA3000 or the all tube SA5.1 w/separate tube power supply unit for about $500. All excellent value and is upgradeable.
OLDER CONRAD JOHNSON PV5. EXCELENT AND A NICE PHONO STAGE... (JUST IN CASE). CAN FIND THEM FOR $650.00 OR SO.
I have owned many of the CJ PV series and think they all have their merits. In your pricerange the PV-10 is a great performer. The sonic equal to the PV-10 and the better of many others is the Van Alstine Super Pas 4i Buffered. Don't let all the hype sway you...this pre is a killer. You can have a new one for your budget and live happily ever after. A tube phono section to boot. Go to AVAHIFI.com and take a look. Best time you will spend today on this subject.
I agree with Sonic Frontiers SFL-1 or SFL-1 Signature-- used one myself for several years. The single tube makes tube rolling inexpensive. Luck. Craig