What are these tubes

Mcfarland, the integrated amp had 6550's in it when I bought it, but I replaced them with KT 88's last year and they're still in good shape.

The unit is not self biasing, and the manual is POOR at best. I don't know how to bias the Raytheon or the Tung-Sol tubes, and the manual doesn't have any information about them. Based on the condition of the power tubes when I got them, I wasthinking it would not be a bad idea to replace the pre-amp tubes.

I don't have any way to take pictures or post them. Sorry.

I don't really do anything on Audio Asylum - I haven't found it to be very user friendly. I'm not really very good at this computer business.

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.