Need tube advice

The plate fuse(KTK 1)on my Conrad Johnson LP70S has blown twice in the last week. This indicates according to the Operation Manual that one of the output tubes - 6550s - has failed. My question to all knowledgeable A'goners : Do I have to get a matched pair from Conrad Johnson or will any matched pair bought on line do? IOWs is brand etc important?
Many thanks in advance.
You don't have to buy tubes from CJ but in my opinion it is a safer purchase because of their high standards and good reputation. CJ may charge more for their tubes but if cost is an issue you can safely buy on-line if the company or individual has a solid reputation. Brand name can be an important factor for sonics and reliability. The following is a recommended on line NOS tube distributer in my opinion: Contact Jashua at ( or phone him at 713-471-5408. I'm sure there are other reliable recommended contacts which will follow my post.
CJ has very particular taste in tubes. Personally, I'd rather try something with a little less bite. Most of the reputable tube dealers out there have great tubes for the CJ. Try: for NOS usa tubes,, for quality tubes. Very pricey but reputable tubes would be from or
YES, you should replace all output tubes together. Otherwise, you will have a variety of problems from unbalanced sound to greatly reducing the life of the new tubes while they compensate for the old ones. Get your tubes tested first?
Buying the tubes from CJ may be pricey but if something goes wrong later. The first thing they will ask "What tubes are in the amp(s)?" Then you can say back "THE ONES YOU SOLD ME!"

I always buy matched power tubes plus one or two just in case, to have on hand. I recommend finding a tube dealer you trust, knows your equipment and sells products you want.

I like Kevin Deal at Upscale Audio. I have always had good luck with his product. I have gotten tubes cheaper elsewhere but in most cases there have been problems. Search the forums and many highly recommended dealers.
Many thanks for the advice/recommendations. As I live in New Delhi, India, I guess my choices are limited. Probably will buy a matched pair of NOS 6550 online and wait for a shipment from the local CJ dealer that could take ages.
Just a quick update. Obtained a quad set of Tung Sol 6550s from Singapore for Singapore dollars 140.The amp is up and running. Have also ordered a quad set of SED 6550C from the Tube store. Excellent service. Now for the interesting bit : the Singapore CJ dealer quoted Sing dollars 695 for a pair of 6550s ie in excess of USD 1000 for presumably the identical tubes that I ordered from tubestore for USD 150 or so. Go figure.
Further update: Tube Store has refunded $6 post purchase on account of a price reduction. Wow now that is outstanding customer service !!