Tube ID and test question

[Planobilly]

Hi guys,

I have a Fender late 60's silver face twin reverb amp. Three of the pre amp tubes are marked RCA 7522 in red and near the top on the other side of the tube they are marked USA 7025.

I can not find a setting sheet for this tube on my TV-10 Navy tube tester.

The data sheet says they are just like a 12AX7 but used where low noise and hum is a requirement.

Can I use the same settings to test as a 12AX7??


Thanks,

Billy

[med6753]

7025 = 12AX7. Use the settings for 12AX7.

[Planobilly]

Thanks,

I assumed as much.

Billy

[gadget73]

The 7025 is an industrial low noise version of the 12ax7.  Basically its a premium part.  Absolutely interchangeable with a 12ax7 though. 

[TimFox]

You may find that the TV-10 and similar military tube testers use too much grid AC drive for a high-mu low-current tube such as the 12AX7 and its variations.
Can you set up a test circuit with another socket?  Measuring the plate current vs. plate voltage at a fixed grid voltage (as on the data sheet characteristic curves) is tedious, but trustworthy.