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
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.
Hi there,the other day ,I blew the 6550we in my pre.First one since ive
owned it.I bought a pair of cryoed off ebay.Hopefully that was the right
thing to do.Im happy with the sovtek sound.Not sure what do go for
next.These have got 1400 hours on them.
I had the same experience as the OP. The email response from Upscale was:

"We received your order, but unfortunately we cannot fill it. The SED 6550C used to be the best tube for your application, however the last batch of tubes to come out of the SED factory before it was shut down, have had issues with a soft vacuum. In products like ARC, Rogue, VTL, and several others, this causes the tube to fail prematurely.

We recommend, as does Audio Research, the Sovtek 6550WE..."

I was lucky in that I have a few extras so was able to use one of those.
Hi,if I put in a winged c,in with the sovetek 6h30,would it change the sound of my pre amp for the better. Thanks