winged c 6550c is not good for ref 5se??


I ordered 3 of svetlanan SED winged C 6550c from 'Upscale audio' last week and it was not shipped until today, so i call them to find out what is going on here.
They told me they didnt send it because " This tube is not going to work well with your audio research amp and it will failed almost every time".
Is it right?
brandon1103
I cannot speak for Upscale Audio but recently Wing C has had quality issues due to damage to their plant.

I bought a couple of hundred matched Wing C a few years ago and used them in my VTL amps. It provided the best sound and remains my favorite 6550 of all time, without exception.

Check with Upscale and see what's going on and what they suggest. Their testing procedures are excellent and they guarantee their tubes.
Kevin Deal is a pretty honest guy. If he declined to ship the Winged Cs, he had a good reason.

Kevin also sells the 6550 WE, which is the tube ARC is currently uses in the power supply of its Ref 5 SE linestage and other input products.

I was surprised that the Tong Sol 6550 sounded pretty good too.
Brandon-

go w/ these guys' advice. The REF5 SE is a very special piece of gear, you do not want to alter its sound/ability to deliver pure listening pleasure. Keep us posted on your tube selection. Happy Listening!
Veerapaneni ... I'm a coward. I bought 6550 WE tubes from ARC for my Ref 5 SE, Ref CD-8 and Phono PH-8 and they 'ain't' cheep. But even if Kevin Deal found a good batch of original "Winged C" tubes they 'ain't' cheap 'neither.'

If you have a hankering to try rolling, call Kevin Deal at Upscale Audio and ask his advice.

Having said that, I buy all of my 6H30s (platinum grade) from Kevin and never had a problem.

OTOH, I've had mixed results with Upscale's KT-120s. Just seems that when sourced from ARC, they bias much closer (within 1 or 2 mV between set tube and slave). It's been more hit or miss from Upscale. Dunno why??? Maybe he matches pairs using different specs than ARC.