matching tubes

[wilebee]

I've bought a box of 50 new 5749's for a compressor project and aside from Plate current and mu what ofther charteristics should I be looking to match of pairs of these?

Wil

Wilebee

 

[Larrchild]

In lieu of a curve tracer, it is desirable to plot the plate current at several increasing bias points, to assure no thumps throughout the GR range and best THD.

 

[wilebee]

very cool I'll make myself a jig with a 5 position switch and stick a current meter across it. thanks

Wil

 

[Larrchild]

exactly.

I've seen excel spreadsheets make sense of it all easier later.

 

[CJ]

Don't forget microphonics and other noise in your "matching" process.

 

[analag]

I love my Tek577 D1 it's great for matching everything and it proved to me the old data sheet curves are lying.