What are these tubes

Almost all tubes are marked with the tube type, but due to environmental conditions the paint frequently falls off. If you will exhale onto the outside of the glass, the moisture in your breath will often make the obsucured lettering legible. Octal tube types frequently have the lettering on the top surface. I find this works for me all of the time. Oh, and don't let your wife catch you doing this. There will just be too many questions to answer.

Viridian should I wait till they cool off first : )?

The numbers you are referring to are mfg. codes. I'm guessing but it might be factory code (230) and date codes (5-52) may mean the tube was mfg'ed either on the 5th day or in the 5th month of 1952.

The Tung Sol 6sl7 and the two Raytheon 6SN7GT's do not require biasing. Therefore, test and replace at will! I say test because the Tung Sol 6SL7 is likely a VERY nice tube indeed. A good source of 6SN7GT, can be found at Andy Bowman of Vintage Tube Services, but Russian, and Chinese varities are plentiful and not bad at all. Try the Electro Harmonix versions, cheap and servicable. Ralph Karsten at Atma-Sphere.com can hook you up with Chinese versions, if you really can't find them anywhere else on the net (Tubeworld, Tube DepotVacuum Tubes, Inc., etc., etc.,). Just Google 6sn7gt and see what comes up. I hope that you had the KT 88's biased when you put them in. If not, get thee to a qualified technician (should not be too hard to find in the Yellow Pages of your area) Electronics professors at local technical colleges may also be able to help you. If you really can't find a good pair of 6SN7gt's, I can sell you a pair or two of mine.

Mcfarland, are the two Raytheon tubes really 6SN7GT's? There is no paint on them at all, so I have no way of determining their lineage.

I did bias the KT 88's when I installed them. I had to since one of the 6550's was pracitically blinding me,it was running so hot.

Do the numbers I gave for the Raytheon tubes indicate their age? The bases of the Tung-Sol and the Raytheon are a dark orange color, if that means anything.

There is a guy here in town that can check the tubes. He has a repair shop that is most definately not geared toward HiFi. For that reason I would be disinclined to buy tubes from him. He is looking toward functionality rather than ultimate quality. Of course you could say that about me considering the integrated amp I am using.