Hm, which order to replace 2 out of 4 tubes?

[hugz]

I have a 2 channel preamp with 2x 6sn7 per channel (4 total). Presumably push/pull?

Unfortunately 2 of the tubes (1 per channel) are horribly microphonic so I'm going to buy 2 new tubes to replace. I'll buy a fancy brand, so I can only afford 2 at a time

For sake of the example, we'll assumre I've thrown out the bad ones, and the remaining tubes are "cheap" but the new ones will be "fancy"

Which setup would be more sensible:

1. Have one "fancy" and one "cheap" tube per channel
2. Have 2 "cheap" ones in one channel and 2 "good" ones in the other channel)

The essence of the question is really "is it a waste of a good tube to put it in the same channel (presumably push/pull) with a cheaper tube?

[tomchr]

I would install them such that you have two identical channels in your amp.

[Michael Koster]

Did you try swapping the 2 tubes within each channel to verify that it's not just the first gain stage that's sensitive?

[hugz]

Originally Posted by Michael Koster

Did you try swapping the 2 tubes within each channel to verify that it's not just the first gain stage that's sensitive?

Both channels were noisy so I moved both of the bad tubes to the same channel. now one channel is noisy and the other is quiet.

Did you mean though to just sap the positioning of the tubes within each separate channel?

Eg the tubes are as follows

..left....right

..1.........2
..3.........4


1 & 2 were both /microphonic, so I moved tube 2 to where tube 3 was. This gave me a noisy left ch and clean right ch

You're suggesting swapping 1 & 3, and 2 & 4 ?

What would I be looking out for if I did this?

Thanks