Tube Suggestions Onix SP3


As a rookie to tubes, one of the Melody 5881s tubes on the Onix SP3 I recently purchased on Agon has gone pzzzsst and I'm clueless and suffering without good sound. I have to keep within a reasonable budget but at the same time have a solid replacement for resale value. Can the original Melody 5881's be had anywhere? Otherwise the tube shop I called said I need to replace all four, rather than only 1 and recommended the NOS Sylvannia 5881 at nearly $90 per. I'm tempted to just buy another used Onix if that's the case. (Just kidding) Help
get2it1
Thanks for the post Tubeears. Here's an update with outstanding news. I contacted John at av123 and they are replacing my amp . . . that's how to stand behind your product! Can't say the same for my CD. I was so thrilled by the Customer Service at AV123 I went on-line and bought a sub-woofer. Now if only all the dealer/distributors would back up their product to secondary buyers like me.
What a winner! And you bought it used. Many dealers/manufacturers would not even have talked to you except to say send it in, we'll fix it, and you'll pay for it! Hope the new one works for you.
I will second that one... literally. My first amp had a bit of a problem and AV123 gave me an RA (return authorization) and sent another amp immediately (before the old one left to go back). My first one had been a "B" stock, but was screwed up in transit. No questions, no problems. They contacted the shipper and had them pick the old one up at my door. The delivery guy was listening to my new one as he left. It just does not get any better than that. AV123 is one of the best companies out there. No bull and a fantastic product at a good price. This little SP-3 will be historical little amp (Dyna 70, Aleph 3, Mac 275, and quite a few more on that list). It has already shaken more than a few heads and caused lost sales for both new and used gear... many times it's price.
I really like the amp (quite obviously) and if I do ever part with it, I'm sure it will be on of those "highly regretted" losses (my old Martin Login CLS's and Rowland 112 come quickly to mind).
I'm glad that everyone is having a good experience with the amp and the company. Nice ink for a change.

Tubby

Hey S3 lovers.....mine just died.  I think a tube is bad, but not sure which one?   First can someone recommend how I can tell?

next, where should i get my new tubes now that AV123 is toast?

Finally, which tube do folks recommend these days (seeing as OP is 14 years old...).

Thanks in advance!
Jason