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How Important is Tube Matching?

I was wondering how important tube matching is for a preamplifier. I had read somewhere that tube matching is extremely important if the tubes were used in an amplifier but was less critical for the preamp. Is this true? I've recently acquired a tube preamp and want to upgrade the tubes but wasn't sure it was worthwhile to pay the big dollars to get matched set(s)...It's a six channel preamp! Any advice would be appreciated.
Thank you!
calgarian5355
calgarian5355
gregm
3,409 posts
 
Do you know how to bias the tubes? If so, don't worry about matching the tubes. It's primarily each channel's L/R that has to be balanced -- which it is in yr Copland (it's one tube)
stevecham
3,340 posts
 
The preamp tube(s) you will benefit from having matched triodes within the twin triode tube itself are the driver tubes. They are responsible for splitting the signal into two 180 degree halves and sending the resulting split signals onto the power amplification stages. This of course is push-pull configurations.
marakanetz's avatar
marakanetz
5,473 posts
 
Tony,
You're wrong.

Preamp tubes don't operate peak to peak. Moreover they often have a large headroom to reach such. Therefore no matching is required.
Don't spend extra on that.
calgarian5355 OP
146 posts
 
Thanks for your help guys! I won't spend the extra $$$ on matched tubes.
marakanetz's avatar
marakanetz
5,473 posts
 
To make this issue(small signal v.s. large signal) more clear first I'll make some definitions:

Small Signal operation is when the tube or transistor operate in the most linear region and never even near peak values.

Large Signal operation is when the tube or transistors operate peak to peak or close to it.

Unmatched large signal tubes will likely have different peak values.
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