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6GH8A Reading Backwards on Tester?

David_NC

David_NC

Super Member
I recently received a pair of NOS GE 6GH8As to use with adapters in place of 7199's in my ST-70. I have a Hickok 533a, so I thought it'd be a good idea to test them before putting them in my amp. The first one tests fine, though I had to use 6U8 settings (I cannot find the settings for 6GH8As anywhere). The second tube pegged the meter past zero, so I flipped the meter reverse switch, and it then read very close to what the other one read in the normal section of the meter. I switched them back and got the same results. Pins seem to be fine, and the tester works properly with the dozens of other tubes I've tested.
Everything I've read about reverse readings says that there's an issue with the tester, but I don't think that's the case here, considering only one tube tests that way. What could cause this? I haven't put that tube in my amp, since I don't know if it'd cause problems or not.
 
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You are using the 6gh8's for the 7199 right?

Put them in the adapters and test as a 7199 and see what you get.
 
Oerets said:
You are using the 6gh8's for the 7199 right?

Put them in the adapters and test as a 7199 and see what you get.
Click to expand...
That is exactly what my next step will be. I was going to do it last night, but I got so involved in listening...
 
Do you have any 6U8s? How they test? For that matter, how does the 6GH8 test on the 6U8 settings? Very similar characteristics.
 
David_NC said:
I recently received a pair of NOS GE 6GH8As to use with adapters in place of 7199's in my ST-70. I have a Hickok 533a, so I thought it'd be a good idea to test them before putting them in my amp. The first one tests fine, though I had to use 6U8 settings (I cannot find the settings for 6GH8As anywhere). The second tube pegged the meter past zero, so I flipped the meter reverse switch, and it then read very close to what the other one read in the normal section of the meter. I switched them back and got the same results. Pins seem to be fine, and the tester works properly with the dozens of other tubes I've tested.
Everything I've read about reverse readings says that there's an issue with the tester, but I don't think that's the case here, considering only one tube tests that way. What could cause this? I haven't put that tube in my amp, since I don't know if it'd cause problems or not.
Click to expand...
Not sure if this will help since it's a different tester, but here are the settings for these tubes on the Hickok 600A:

6GH8.png
6U8.png
7199.png
 
David_NC said:
I recently received a pair of NOS GE 6GH8As to use with adapters in place of 7199's in my ST-70. I have a Hickok 533a, so I thought it'd be a good idea to test them before putting them in my amp. The first one tests fine, though I had to use 6U8 settings (I cannot find the settings for 6GH8As anywhere). The second tube pegged the meter past zero, so I flipped the meter reverse switch, and it then read very close to what the other one read in the normal section of the meter. I switched them back and got the same results. Pins seem to be fine, and the tester works properly with the dozens of other tubes I've tested.
Everything I've read about reverse readings says that there's an issue with the tester, but I don't think that's the case here, considering only one tube tests that way. What could cause this? I haven't put that tube in my amp, since I don't know if it'd cause problems or not.
Click to expand...
I would not be too much concerned if the tubes works and sounds fine in the amp. It's the ultimate test !
 
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