REF5SE tubes

I bought mine from Tube Depot and The Tube Audio store, same prices as Upscale, "matched" supposedly- though matching on these is not so important according to ARC and others (for power tubes it is though).

Having used both Tube Depot and The Tube Store in the past, I would highly recommend Brent Jessee at audiotubes.com.  

He is well respected and can give you his personal recommendations. 

Tubes should be available now from ARC. I have a Ref 5 SE and got tired of waiting for ARC to replenish their stock. They said they had to reject 90% of the tubes they were getting in. So I bought tubes from other vendors and lost the ARC "magic" sound. While hopefully waiting for those tubes to "burn in", ARC notified me that they finally had my tubes in stock so I ordered a set for spares. When they arrived I thought I'd switch them out with the ones I had previously purchased and right away the magic was back! So I am recommending ARC's matched sets, they are picky for a reason.

I've often bought tubes from Music Direct and never had an issue.

+ 1 million for Brent Jesse. Every time I’ve dealt with him has been an excellent experience! Every single time.