Mod50 preamp tube replacement...thoughts, recommendations?

[bkd_guitarist]

I've been a bit uninspired by the tones coming out of my SL2 module lately. It's sounding rather soft and unaggressive, and it's pretty noisy...lots of hiss on the higher gain channel. My power tubes are relatively new, so it occurred to me that a replacement of the preamp tubes in the module might be in order. These are the original 12AX7's that came with the module when I bought it new in 2007...I know preamp tubes don't need to be replaced as often as power tubes, but does it sound like it might be time?

If so, any recommendations on particular preamp tubes? For frame of reference, I play classic rock covers, modern alt rock and pop covers, and I play in a loud, rock-oriented P&W band. I favor pretty raw Plexi and JCM800 tones with aggressive mids. Hope that helps. Thanks!

 

[drewiv]

In gain module, such as the SL2, I generally like a Ruby HG+ in V1 (if you're looking at the module from the front, it's on the left). I find very little difference no matter what tube I use in V2, just make sure it's a good tube.

 

[bkd_guitarist]

In gain module, such as the SL2, I generally like a Ruby HG+ in V1 (if you're looking at the module from the front, it's on the left). I find very little difference no matter what tube I use in V2, just make sure it's a good tube.

Thanks, those look pretty good. Any other recommendations before I pull the trigger?

 

[drewiv]

In gain module, such as the SL2, I generally like a Ruby HG+ in V1 (if you're looking at the module from the front, it's on the left). I find very little difference no matter what tube I use in V2, just make sure it's a good tube.

Thanks, those look pretty good. Any other recommendations before I pull the trigger?

Oh, man. Check out the MTS forum. All kinds of tube tomfoolery going on in the modules.

 

[bbaug14]

Also, don't forget about the preamp tube and PI tube in your MOD50. V1 is actually in the amp, not the modules.

 

[drewiv]

Also, don't forget about the preamp tube and PI tube in your MOD50. V1 is actually in the amp, not the modules.

While technically true that V1 is in the amp, it has minimal influence on the tone. The tube you really want to mess with is V1 in the module. The PI in the amp can make a big difference.

 

[webrthomson]

Ruby's are great - nice tubes. I'd stick a 5751 in the amp PI (the JJ's are pretty cheap, but the JAN Philips are good too, if very expensive) ;-)

Like Drew says check out the MTS forum, tube madness that way lies...

 

[bkd_guitarist]

In gain module, such as the SL2, I generally like a Ruby HG+ in V1 (if you're looking at the module from the front, it's on the left). I find very little difference no matter what tube I use in V2, just make sure it's a good tube.

Thanks for this recommendation. I went with a Ruby HG+ in V1 of the module as you suggested, and a Ruby 7025SS HG in V2. Dramatic improvement in the noise level. My band plays pretty loud - I run the Mod50 in full power mode with the master volume around 2 o'clock, and the B channel of the SL2 module sounded like a roaring waterfall with the old tubes. MUCH quieter now, and it seems to have restored some of the bite. I experimented with replacing the tubes in the amp chassis as well...didn't hear any differences there, so I'm leaving the old tubes in there for now. Thanks again!

 

[drewiv]

In gain module, such as the SL2, I generally like a Ruby HG+ in V1 (if you're looking at the module from the front, it's on the left). I find very little difference no matter what tube I use in V2, just make sure it's a good tube.

Thanks for this recommendation. I went with a Ruby HG+ in V1 of the module as you suggested, and a Ruby 7025SS HG in V2. Dramatic improvement in the noise level. My band plays pretty loud - I run the Mod50 in full power mode with the master volume around 2 o'clock, and the B channel of the SL2 module sounded like a roaring waterfall with the old tubes. MUCH quieter now, and it seems to have restored some of the bite. I experimented with replacing the tubes in the amp chassis as well...didn't hear any differences there, so I'm leaving the old tubes in there for now. Thanks again!

Glad I could help. I've never noticed much difference with the tubes in the amp either, but it does sound as though you had a bad tube somewhere in your module (from your description). I do like a Sovtek 12AX7LPS in the PI location in the amp, other than that - not much to my ears.