Tube Tester


Just replaced vacuum tubes in my amp. Had a power fault. Replaced the whole right channel because I did not know which tubes actually failed.  
 

Brought back up the idea of getting a tube tester. I have searched for them a few times and have a hard time figuring out their differences and quality.

Any of you have recommendations for me on how to navigate a tube tester purchase?

 

Thanks in advance 

pgaulke60

Agree with Viridian that you want a tester that measures transconductance. And that usually means Hickok or B&K (often made by Hickok.) Transconductance of a given tube varies with plate voltage and current. Unfortunately very few vintage testers are capable of providing adequate voltage and current for power tubes. Hence you may get a misleading reading for transconductance. Best to test power tubes in the amplifier where you can know plate V and current by direct calculation. And measure grid bias as a guide to tube wear. For big bucks you can get a modern tester that does a proper job, but IMO it’s not needed.

Searching for a bad tube is pretty easy. I always have a spare set. You just substitute one at a time until you find the bad tube... or eliminate the problem from being a tube. Most companies that supply matched tubes write down their electrical test results on the box or tube, so you can order a single tube matched replacement. 

Recently purchased a BK Dyna Jet 707 tube tester on Ebay.

Sent it off to another 

Ebay gentlemen that refurbish and calibrated it. All in less than $350.

Works great.