SWR Marcus Miller Pre-Amp - Replacing Tubes

[Barefootbassplayer]

For a while now I have been noticing the tone of the SWR becoming more distorted the longer it is left on, which actually sounds nice but I use this for a clean sound and have no control!!

I'm thinking it could be the tubes although this is not something I am particularly familiar with. I have had a friend tell me tubes should be renewed every couple of years? I have had this since they first released them back in 2008 or whenever it was and it has been very well gigged in that time!

I know it uses a 12AX7 Dual Triode tube.......what ever the hell that is, if anyone knows where I can get these from and also tell me if they are relatively straight forward to replace. I can replace fuses, make cables, diagnose a few standard faults so not a complete newb to electronics although i am no electrician!!!


Thanks for your help guys

[voxpop]

A 12ax7 is the same valve as an ecc83.
Check out Watford valves for info and prices.

[davehux]

There are a few guys on here selling valves if you search the Other Musically Related Items thread. Swapping and comparing brands is a perennial hobby for the keen valve amp owner

Normally the valves sit in a ceramic holder and it's just a matter of gently 'wobbling' them as you pull them up out of the holder. Replace the new ones in the same way, once you've lined up the gap in the pins with the gap in the holder. No soldering or physics degrees normally required