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.

Thanks in advance!



I sourced my tubes from Tube Amp Doctor when I owned Ref 6. If you can swing it, try the ultra rare Reflector 6H30n-DP (made before end of 1992) tubes that includes gold grids. As far 6550, I highly recommend trying SVETLANA Winged "C" 6550C is an amazing rectifier. It has very controlled sound - nothing offensive can be found in any part of the frequency response. Also very consistent in detail and separation, with clean highs and exceptional balance throughout.

@lalitk thanks but that’s a bit higher than the budget for new tubes. Will keep this info in mind though just in case. Is there a difference between 6550WE and C?

@facten thanks! Have you had good experience with Viva Tubes?


The SVETLANA Winged 6550C was definitively better for the aforementioned improvements heard over the stock Sovtek 6550WE.

I’m going to give ARC a call tomorrow..but…

What is the difference between Sovtek 6550WE, Svetlana 6550C and the Electro-Harmonics 6550EH? Does anyone know if the 6550EH is compliant?

@audphile1 Yes I have purchased KT88s ,as well as ,NOS 7189A tubes from VivaTubes, no issues and quick shipment.


@testrun  I was also going to recommend BrentJessee but unless audphile1 is interested in NOS GE 6550s Brent doesn't have any others in stock according to his webpage

I’ve bought a few sets of power tubes from Viva Tubes, and they’ve all been good. They’ve been low on Russian power tube stocks for months, but still have some of those Sovteks, plus EH and Mullard KT88. You can also use KT88 or KT90 in the Ref 6 btw. I’ve heard EH KT90 is the best sounding choice (I’ve used Gold Lion KT88 in Ref 6, but not an EH KT90 myself) but you’ll have to run with acrylic top off due to height.

I’ve also used Brent Jesse GE 6550 in the Ref 6 and those are excellent, and reasonably priced. The Sovtek 6550 is OK but I’ve preferred the other tubes I’ve tried.

I bought some EH Gold 6SN7 from Tube Store a couple years ago and they almost immediately sputtered in my amps. That’s soured me on them as a source.

Upscale Audio tubes have always been 100% reliable and I’ve bought a TON of them over the years. If you’ve been a regular customer of theirs in the past, give ’em a call and they’ll work with you.

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.