I came across an ancient primative strobe tuner in the school storage room, oddly enough it was in brilliant internal condition. Knowing me, I raped its tubes thinking I might be able to get some use, or money, from them.

All the following tubes are in perfect condition and read

77-48-30 C.G.CONN LTD.
188-5 made in U.S.A

4 x 6V6 GT
1 x ECC83
1 x 6SC7

The following are unmarked except for their names

1 x 5U4GB
1 x 5Y3 GT
1 x 6SN7 GT3

Any info would be appreciated.
I know the 6V6 is used as a power tube in some amps. The 5U4GB sounds like it could be an exchange for the preamp tube. The ECC83 sounds familiar. I would post this in the "Gear Building and Customizing" thread if you don't get satisfactory responses here. Also check the internet. I just typed in 5U4GB and found out it is a black plate rectifier tube.
I know that the 6v6 are poweramp tubes, the 5u4 and 5y3 are rectifier tubes, and the ecc83, 6sc7 and 6sn7 are preamp tubes, but thats all I could figure out.

Think emailing Conn directly could be of any help?
You might be able to download a circuit diagram on the thing that would tell you. If its very old that may not be an option. Hang around, there are a lot more knowledgable forumites than I. You could try emailing some boutique amp makers, they might be nice enough to help, might even get an offer.
Ecc83 are the same as 12AX7. 6Sc7 is a rather rare preamp tube, used in the 50s mostly. The 6SN7 is a preamp tube, most notably used on the Komet Concorde amp, which was discontinued because 6SN7s are so hard to find.
If you can get pictures of them I may be able to identify them. I'd also be interested in buying some of these tubes, so PM/email/AIM me if you want to sell and we can work out a price.
Last edited by Roc8995 at Sep 26, 2007,
I will get pictures to you tomorrow, tonight I need my sleep. Thanks for the info!