What will removing some preamp tubes do?

[Pink Unicorn Horsey]

I've got an AC30 RI and read someplace that I can get more gain from one channel if I remove the preamp tubes from one of the others.

This amp has three channels: Normal, Brilliant and Vibrato. There are six preamp tubes; we'll call them 1, 2, 3, 4, 5 and 6. The Normal channel uses tubes 1 and 3, the Brilliant channel uses 1, 2 and 3, and the Vibrato channel uses 4, 5 and 6. I never use the Vibrato channel but would like to continue using the Normal and Brilliant channels. I specifically would like to use the Normal channel for overdriven, Brian May-esqe tones while using the Brilliant channel for chimey Beatlesque tones.

My hope is to increase overdrive by removing the Vibrato preamp tubes. Will doing so achieve the desired effect? Are there any dangers? Any side effects? Should I ask my doctor or pharmacist?

- Keith

 

[Gearjoneser]

Re: What will removing some preamp tubes do?

Those amps are fairly prone to tube related breakdowns, so I wouldn't even think of doing that. It's very likely that if you remove any, you won't get any sound. You could probably remove the reverb/trem driver tube, but I doubt it would have any positive effect on the tone.

The best idea is to get a high quality clean boost OD to push the amp a little harder. Also, change out all the stock tubes to JJ EL-84's and GT12AX7C's.

 

[Pink Unicorn Horsey]

Re: What will removing some preamp tubes do?

Those amps are fairly prone to tube related breakdowns, so I wouldn't even think of doing that. It's very likely that if you remove any, you won't get any sound. You could probably remove the reverb/trem driver tube, but I doubt it would have any positive effect on the tone.

The best idea is to get a high quality clean boost OD to push the amp a little harder. Also, change out all the stock tubes to JJ EL-84's and GT12AX7C's.

My understanding is that the best tubes for this amp are NOS Mullards (on the endangered species list), Sylvania or GE.

 

[James Rock]

Re: What will removing some preamp tubes do?

JJ's are really chimy sounding so for beatlesque sounds i would use them.

 

[The Golden Boy]

Re: What will removing some preamp tubes do?

Dropping a Mullard into the V1 slot will do wonders for whatever else tubes you have.

 

[the guy who invented fire]

Re: What will removing some preamp tubes do?

an AC-30 (or any Vox for that matter) is not an amp you really want to mess with...they are just very finicky amps that always seem to be running on the edge...be very careful with your Vox...

 

[Pink Unicorn Horsey]

Re: What will removing some preamp tubes do?

Dropping a Mullard into the V1 slot will do wonders for whatever else tubes you have.

You got any spare Mullards hangin' 'round the house?

 

[The Golden Boy]

Re: What will removing some preamp tubes do?

Sorry bro, the ones I've been able to scavenge are in use!:34:

 

[Pink Unicorn Horsey]

Re: What will removing some preamp tubes do?

Sorry bro, the ones I've been able to scavenge are in use!:34:

B*stard! You dangle the carrot...

 

[jdm61]

Re: What will removing some preamp tubes do?

I have a spare Mullard that came out of my stereo preamp.....would i get any benfit from puitting it in the first slot of my newly aquired 50w plexi RI?

 

[Gearjoneser]

Re: What will removing some preamp tubes do?

My understanding is that the best tubes for this amp are NOS Mullards (on the endangered species list), Sylvania or GE.

It depends on what you want. I suggested tight sounding highgain pre tubes, only because I know it'll 'kick it up a notch!' Chinese pre tubes will do that.
NOS Mullards will give it a nice sweet sound. GT Mullard copies will give you even more gain than NOS versions, but aren't as focused sounding as the GT-C's, and not quite as sweet as old 'made in Britain NOS Mullards.

Even still, the best option is to start listening to different clean boost OD's with AC-30's, and see which one has the right kind of gain.

 

[Pink Unicorn Horsey]

Re: What will removing some preamp tubes do?

Sage advice, my gear-jonesing friend. I'm always curious why and how different modifications affect tone. This particular question came after reading some things about Brian May's AC30 mods. I'm curious about what variations on these mods would accomplish.