Paired pre amp tubes?

Laurent · #1 10-20-2010, 10:54 PM

Should pre amp tubes be the same or do you get better results with odd pre tube amps? Does it even matter?

For example two 12AX7 Tung Sol versus a 12AX7 Tung-Sol paired with a Sovtek 12AX7LPS?

I understand pairing power tubes and getting the proper bias.
My question only relates to pre amp tubes in V1 & V2 position.
Your insight would be appreciated.

I have personally always paired odd pre amp tubes with good results but this does not make it right!

JimmyM · #2 10-20-2010, 11:16 PM

no need to pair pre tubes. pre tubes don't need to be matched or biased.

Laurent · #3 10-21-2010, 01:43 PM

Quote:

Originally Posted by JimmyM

no need to pair pre tubes. pre tubes don't need to be matched or biased.

Understood. But are there any benefits in pairing same brand/same tubes?

BassmanPaul · #4 10-21-2010, 02:02 PM

Quote:

Originally Posted by Laurent

Understood. But are there any benefits in pairing same brand/same tubes?

Some people say that they can hear a difference between a 12AX7 made by one company and a 12AX7 made by another. Real or imagined I'll have to take their word. With my abused ear 'oles I've not noticed a difference.

That said when I retrofitted JJ ECC83s into the pre-amp I designed I was happier with the unit BUT I cannot tell you why.