Cut/Boost tone circuit for boost circuit.

[RockinRocket]

Im looking for a Cut/Boost, Treble/Bass tone circuit that will allow me to mainly boost the mids for a boost circuit. Im thinking the Vox circuit might be the place to start but was unsure if that was the best choice. I was also hoping that with the Cut/Boost was centered (12oclock) the it would neither cut or boost. Is this how The Vox circuit works? Thanks for the help!

[RockinRocket]

I found on the Duncon tonestack calculator the James tone circuit, a common circuit from Orange amps. This seems to be what Im looking for. With treble and bass centered at noon it neither cuts or boosts. However one problem is it looks very lossy. Everything at noon is negative 21 dbs. For a single 12ax7 with the tone stack after the first triode Im working on values for the first and second triode to have enough drive to boost the from end of another amp for a boost pedal.

Is there any advice any of you folks have regarding the James circuit or concern you see that might arise with this? Thanks

[wyatt]

The James tone stack is PASSIVE, passive tone stacks don't allow any boost of the signal (there is no where from the energy to come from, all they do is cut. That's why's it's so lossy...it builds in the "headroom" from the circuit to mimic the boost....it's not a boost, it's just less cut.
http://www.thermionic.info/james/James_ ... ontrol.pdf

It's usually confused with the Baxandall tone stack, many people even use the name "Baxandall" when describing a James tone stack.. The two are incredibly similar in how the controls behave. But the Baxandall circuit is ACTIVE.
http://www.thermionic.info/baxandall/Ba ... ckTone.pdf

Both are excellent circuits, are variations were commonly used by Orange, Ampeg, Sunn and others.

Since you asked about Vox...Vox used a passive, cut-only tone stack, as did Marshall, Fender, and 90-95% of guitar amps. Active tone stacks aren't uncommon, especially in large , modern "kitchen sink" amp designs but many are very complicated, using dedicated op-amps for the amplification to boost the signal.

[RockinRocket]

The James tone stack is PASSIVE, passive tone stacks don't allow any boost of the signal (there is no where from the energy to come from, all they do is cut. That's why's it's so lossy...it builds in the "headroom" from the circuit to mimic the boost....it's not a boost, it's just less cut.
http://www.thermionic.info/james/James_ ... ontrol.pdf

Well that shouldn't be a problem for a dual triode boost circuit would it? Just looking for a circuit to be able to eq for a mid bump for solos. Then the second triode would up the signal to boost the preamp of the amp. Or perhaps the tone stack is so lossy the second triode wouldnt produce enough drive as a boost?
Thoughts?

[wyatt]

Using another gain stage to boost/recover is just fine. But boosting the signal after the tone stack is different than having an active tone stack for the purposes of a technical conversation. Is this getting built into an amp? Or as a separate boost?

There is no reason your plan won't work, BUT you may be reinventing the wheel...a parametric EQ would be existing, "more perfection" solution. For tone sculpting and a mid boost, it's worlds ahead of a tone stack and gain stage. I can understand wanting to just build something DIY for the challenge or to build into an amp...but at the very least, I wouldn't be looking at tone stacks as much as I would equalizers, especially a guitar-centric parametric EQ.

[statorvane]

Well, here is some info about active tone circuits.

http://www.thermionic.info/tonecontrols ... ntrol.html

[gingertube]

Rockin',
most of the time the trick is knowing what "label" to search for.
Try searching "TILT" + "tone control". That is the usually applied name for these boost/cut controls.
Cheers,
Ian