Baxandall tone stack mod

C

Classic 59

Member
Has anyone ever done a Baxandall tone stack mod on their amp?

It's my understanding Steve Vai does this to his amps.

I am interested in doing it to my Metro 12,000 amp.

Thanks!
 
If a Baxandall tone stack sounded any good, Bogner, Friedman, Cameron, Fortin, and everybody else would be doing a "Baxandall mod" and charging big bucks for it.

They're not.

Because it sounds like poo in a guitar amp.

Don't waste your time.
 
The Baxandall tone stack is much more powerful and versatile than the FMV tone stack.
I have a few amps with it and much prefer it.
I did not modify anything. The amps came stock with the baxandall tone stack.
 
If you can shoot me a solid resource, drop by a link. I am capable of Googleing but I want a solid resource.
 
Everyone calls it a Baxandall, but it's actually a James tone stack. Baxandall is active. The James is very similar and passive.
I don't have a link.... I just know them from using them for over 40 years.
I've never played on a amp that was modified to the Baxandall tone stack.
Ampeg, Orange,THD, etc....have all made amps with the Baxandall tone stack.
 
Yeah, the original Baxandall was an active tone stack, and the passive version as you would use in an amp is the James. Less insertion loss than a TMB stack, and you basically only control the bass and treble. The mids zoom right through ( minus the insertion loss ).
I suppose it might sound OK if the amp was designed around it as mentioned above.

A better idea if you want to mod a TMB style amp might be to install a tone stack lift switch, where you disconnect the mid pot from ground, essentially lifting the stack out of the circuit. Bogner did this on the Helios, but I can't remember what he called it.
I like this mod with an increased resistance to ground vs a complete lift. I've had success with anywhere from 15k - 27k inserted between the mid pot and ground. You can tune to taste.
This will give you a large mid and volume boost when engaged.
 
fusedbrain":3nedce8r said:
Yeah, the original Baxandall was an active tone stack, and the passive version as you would use in an amp is the James. Less insertion loss than a TMB stack, and you basically only control the bass and treble. The mids zoom right through ( minus the insertion loss ).
I suppose it might sound OK if the amp was designed around it as mentioned above.

A better idea if you want to mod a TMB style amp might be to install a tone stack lift switch, where you disconnect the mid pot from ground, essentially lifting the stack out of the circuit. Bogner did this on the Helios, but I can't remember what he called it.
I like this mod with an increased resistance to ground vs a complete lift. I've had success with anywhere from 15k - 27k inserted between the mid pot and ground. You can tune to taste.
This will give you a large mid and volume boost when engaged.
Click to expand...

are we talking literally adding a switch that grounds from the mid pot? what style switch would you recommend? like a traditional fender bright or deep switch?

is this how the orange rockerverb mki's are? (i love mine).
 
On all TMB tone stacks one side of the mid pot is connected to ground, and this is the ground point for the entire tone stack.
So to do this mod, you would remove the wire from the mid pot's ground connection and connect it to a switch, then connect the other side of the switch back to the ground point. When the switch is open, the tone stack is removed from the circuit creating a large mid and volume boost.
If the boost is too much, the other way to do it is to replace the mid pot's ground connection with a suitable resistor, and then use a switch to jumper the resitor. Again, when the switch is open the mid pot will be partially grounded through the resistor giving you a mid and volume boost, and when the switch is closed the resistor is shorted and you have a normal TMB stack.
Any good quality mini toggle will work, or you could replace one of the tone pots with a pot of the same value but with a push / pull switch on the back.
Obviously, this mod is suggested for turret board / handwired amps like the OP's 12 series Metro or similar. It would be much much harder to implement on a PCB based amp.
Not sure about the Rockerverb you mentioned, I haven't looked at a schematic for that amp.
I know this type of switch is standard on the original Bogner Helios, and can also be seen in the Vox handwired series amps as a "Hot /Cool" switch. On my AC 30HW, the full lift was too much so I have a 22k resistor in there now.
I know a couple of guys that loved the sound of the original Helios with the EQ bypassed. It's a really in your face raw tone for sure, and sounds killer on Plexi style amps.
 
A few people said they real like the tone stack bypass used as a lead channel. I have not tried it other than the amps that have it stock mentioned above.
 
stephen sawall":f9j0pntj said:
A few people said they real like the tone stack bypass used as a lead channel. I have not tried it other than the amps that have it stock mentioned above.
Click to expand...
Very similar to all tone knobs cranked. Personally I think it sounds bad in room, but good recorded
 
scottosan":16usdha6 said:
stephen sawall":16usdha6 said:
A few people said they real like the tone stack bypass used as a lead channel. I have not tried it other than the amps that have it stock mentioned above.
Click to expand...
Very similar to all tone knobs cranked. Personally I think it sounds bad in room, but good recorded
Click to expand...
Yeah, not a tone you would want to use all the time. Nice on a switch though.
It's foot-switchable on the Vox's.
Would have been great to have it on a foot switch with the Helios, but they missed a whole bunch of opportunities on that amp.....
 
When I get around to it I will see if I can do it on my blue voodoo lead channel. It has been modded a ton and is my gunnea pig for a lot of things.
 
I think the Framus Cobra is a SLO with a James stack
James stacks get used more often on clean channels, after the first gain stage e.g. Marshall 2210 etc
 
You must log in or register to reply here.
Back
Top