# Matching radio tubes - what is widelly accepted tolerance in parameters?

When matching radio tubes, most important parameters are anode current and transconductance. Is there widely accepted tolerance in parameter variation? I have read an article where tubes are considered as matched if anode current is within 5% static Ip and transconductance S variation is 10%.

• I suggest you visit diyAudio.com/hollow_FETs or whatever they are presently using as a euphemism for tubes. Read their forum, for needed tolerance for left-right channel matching. – analogsystemsrf Mar 19 '17 at 22:58