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Fender Passive Tone Stack
- Thread starter xray
- Start date
well, I'd agree to a point. The concept of the 'classic Fender tone stack" has been around for a loooong time and players with much experience (read=old) are probably aware of this. OTOH, I guess if you were a total bass noob, it would be helpful to have this in the manual. But, if you were a total bass noobie, it would be surprising to find you were starting your bass playing life out with a Fender Superbassman.
If you are .. man, good for you. and good luck with it.
just remember "flat" is not necessarily where you want your tone, so don't get hung up on that too much.
Get this app and install it to get a visual image of what the tone stack does:
Tone Stack Calculator
I'm a big fan of that Fender classic tone stack. Ironically, the
circuit that realizes this is dirt simple.
Tone Stack Calculator
I'm a big fan of that Fender classic tone stack. Ironically, the
circuit that realizes this is dirt simple.
The classic Fender tone stack is a passive circuit. It cannot add or boost anything. It can only cut or let some frequencies through. The controls are interactive, in that if you change one control, the action of the other two controls will be different. There is no "flat" setting. The closest you can get to flat is 0-10-0 and that is not exactly flat. But do you want "flat"? There is an inherent mid cut in a Fender tone stack (and it's called a stack because that's what the circuit looks like on the schematic.) That mid cut tonality is what we know and love about Fender amp tone. If you do set it "flat" (0-10-0) it sounds pretty awful. Marshall, Mesa, Vox and many others use a similar inherent mid cut tone stack. The response is a bit different, voiced a little different, but they are a lot like Fender's.
Turn all three controls down, and nothing gets through. As you turn the bass up, bass frequencies are let through. Same with the treble. The midrange works a little differently as it lifts the ground connection from the whole stack. All frequencies are raised when the mid is turned up, but our ears hear it as a mid increase. If the mid control is large enough eventually turning it up will make the bass and treble controls pretty inactive. Fender generally uses 10k mid controls...others use 25K for more range. Generally 25k is as large as you should go with a Fender, and 50k is as large as you should go for a Marshall without losing the bass and treble controls.
Contrast this with an Ampeg or Carvin, both which use Baxandall bass and treble controls. Although passive, they act as boost and cut controls, as active controls would. Mid points are flat, and you can boost or cut the bass and treble. The controls are not interactive.
Ampeg then adds an active, inductor based boost and cut midrange which is very effective. In their guitar amps, Carvin has a simple, much less effective midrange, which works a bit like the Fender mid, lifting the bass control's ground or reducing the resistance to ground.
Most active preamps in basses use active controls with actual boost and cut controls, either baxandall (not that common) or true active. Shadowsky uses EQ like the Fender passive controls with interactive passive controls. I've only seen one reverse engineered schematic. There may be Shadowsky preamps that use active controls.
In Fender designs with no midrange control, the mid pot is replaced with a resistor set where a mid control at about 2/3's of the way up.
Turn all three controls down, and nothing gets through. As you turn the bass up, bass frequencies are let through. Same with the treble. The midrange works a little differently as it lifts the ground connection from the whole stack. All frequencies are raised when the mid is turned up, but our ears hear it as a mid increase. If the mid control is large enough eventually turning it up will make the bass and treble controls pretty inactive. Fender generally uses 10k mid controls...others use 25K for more range. Generally 25k is as large as you should go with a Fender, and 50k is as large as you should go for a Marshall without losing the bass and treble controls.
Contrast this with an Ampeg or Carvin, both which use Baxandall bass and treble controls. Although passive, they act as boost and cut controls, as active controls would. Mid points are flat, and you can boost or cut the bass and treble. The controls are not interactive.
Ampeg then adds an active, inductor based boost and cut midrange which is very effective. In their guitar amps, Carvin has a simple, much less effective midrange, which works a bit like the Fender mid, lifting the bass control's ground or reducing the resistance to ground.
Most active preamps in basses use active controls with actual boost and cut controls, either baxandall (not that common) or true active. Shadowsky uses EQ like the Fender passive controls with interactive passive controls. I've only seen one reverse engineered schematic. There may be Shadowsky preamps that use active controls.
In Fender designs with no midrange control, the mid pot is replaced with a resistor set where a mid control at about 2/3's of the way up.
that is the most concise description of the fender tone stack I've ever read, you sir, know your ----
May I add, I think the heart of Ampeg tone is the combination of the Baxandall bass and treble, and the inductor based active midrange. All Ampegs with these sound very Ampeg to me, while the times Ampeg tried a different mid scheme sound different.
I have finally come to understand the "tone stack", the link to the tone stack calculator is what helped me "visualize" what is actually going on. I no longer hate them since I can now "wrap my head around it". Steve's post is the best description I have ever read to explain it but it wasn't until I messed around with the calculator that I could actually see the interaction happen.
