Help? 36wt build squeals with anything but NOS Mullard in PI
Posted: Sat 05/15/10 11:30 pm
This is in my Weber 36wt Plexi build... It's a Weber 36wt Marshall (EL84's) with a few upgrades. I had a buddy build it to these specs for me.
It's got a post phase inverter master volume and a footswitchable mid boost with a 5-way selectable "voicing" control.
I'm glad I got the 36wt version, I'm not sure 18wts would have worked for me needing a clean tone at levels I can hear them with my loud drummer.
I had some problems with the power tubes, but after swapping them out I've ran into another issue.......
I cannot put any other tube but a NOS Mullard in the phase inverter socket. All other tubes are noisy and squeal real bad, some worse than others.
I've tried 12 different preamp tubes - GT, JJ, Mesa and a Sovtek 12ax7 as well as a GT and JJ 12at7 and they all squeal.
Any reason you can think of that would make it do this? I might add that I'm not skilled or have much knowledge in building amps, so please
don't use big words with me
Here's some pics, that jack by the PIMV is the footswitch for the mid-boost:
http://img704.imageshack.us/img704/4645/pict0190d.jpg
http://img188.imageshack.us/img188/8778/pict0187u.jpg
http://img705.imageshack.us/img705/1900/pict0146a.jpg
http://img19.imageshack.us/img19/7220/pict0145ko.jpg
http://img189.imageshack.us/img189/3243/pict0144zc.jpg
http://img121.imageshack.us/img121/1743/pict0148g.jpg
It's got a post phase inverter master volume and a footswitchable mid boost with a 5-way selectable "voicing" control.
I'm glad I got the 36wt version, I'm not sure 18wts would have worked for me needing a clean tone at levels I can hear them with my loud drummer.
I had some problems with the power tubes, but after swapping them out I've ran into another issue.......
I cannot put any other tube but a NOS Mullard in the phase inverter socket. All other tubes are noisy and squeal real bad, some worse than others.
I've tried 12 different preamp tubes - GT, JJ, Mesa and a Sovtek 12ax7 as well as a GT and JJ 12at7 and they all squeal.
Any reason you can think of that would make it do this? I might add that I'm not skilled or have much knowledge in building amps, so please
don't use big words with me
Here's some pics, that jack by the PIMV is the footswitch for the mid-boost:
http://img704.imageshack.us/img704/4645/pict0190d.jpg
http://img188.imageshack.us/img188/8778/pict0187u.jpg
http://img705.imageshack.us/img705/1900/pict0146a.jpg
http://img19.imageshack.us/img19/7220/pict0145ko.jpg
http://img189.imageshack.us/img189/3243/pict0144zc.jpg
http://img121.imageshack.us/img121/1743/pict0148g.jpg