Reliable source for 6550WE tube - Audio Research Ref 6


Re-tubing an ARC Ref 6 and seems like the 6550WE tube is hard to come by these days. Upscale only sells to Primaluna owners, Tube Depot has it on backorder. 
The only other source for this tube that I was able to find is The Tube Store. Any comments on quality of their tubes?

Also, thinking to replace the Sovtek 6H30 with EH 6H30 Gold Pin tubes.
Thoughts?
 

Thanks in advance!

128x128audphile1

Another lesser known source is Amplified Parts. They cater mostly to the musicians crowd but have lots of tubes.

Ended up ordering the EH 6550 from Upscale Audio. 
After 10 hours of “on” time, I like what I’m hearing so far and it’s an improvement over the stock Sovtek 6550. Now, that tube had about 2400 hrs on it and may be this is an improvement just because the Sovtek was at end of life, not sure, but I am hearing a more balanced presentation top to bottom, a but more air and more extended highs. Mids are a bit more relaxed. Slight improvement in bass definition and speed as well - it’s less loose now. Didn’t know what to expect but that’s what I’m hearing and it’s very nice!

Probably worth swapping the stock Sovtek 6H30 tubes for a fresh set of EHs as well.