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onboard passive mid control

#6
Daniel Elliott said:
If you can do it on an amp, I don't understand why you couldn't do it on a bass. What about the pickup makes it undoable?
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the controls in your amp are active.

and also the tone control in a passive bass is only a CUT, you cant boost frerqs. so if you add a mid control it would be a mid cut and not boost
 
#8
dadodetres said:
the controls in your amp are active.

and also the tone control in a passive bass is only a CUT, you cant boost frerqs. so if you add a mid control it would be a mid cut and not boost
Click to expand...


GK amps use active eq controls, but the old fender bassman has passive tone controls.

The bluEQube does what I want but it's an on/off solution. I'd like to be able to adjust the amount of cut with the knob.
 
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#11
Its "off" position on the knob is set for a specific cut for an auto slap tone. I don't recall what level of cut it is in that position, but Im sure Sheldon could maybe answer that. Basically the off switch is no cut, with it switched on it starts at say -3db and goes up from there, if that makes sense?

Its possible Sheldon could make you one with exactly what you want too. His user name is Sheldon D., just shoot him a PM. Might have to wait a bit for a response, he is pretty busy at the moment :)
 
#13
Yeah it used to be a push/pull on the volume, but now it has its own knob and a switch instead. But yeah, Sheldon designed it as far as I know, along with his 4-way position switch for p'ups, so its very possible it could be modified to what you need.
 
#15
Daniel Elliott said:
the old fender bassman has passive tone controls.
Click to expand...
The circuits used in amps have gain circuits that make up for the losses. When you have the controls set midpoint* the entire frequency range has a loss; for your typical Fender type circuit, it's between 22 and 26dB. When you "boost" with one of these controls all you are doing is making the circuit have less loss in that frequency range of the control, not any actual gain. When you cut, it's just more loss of level. The amplifier stage before and/or after the passive tone control makes up for the loss introduced to get your signal levels (at least) back up to where they were before.

Also, amplifier stages have output impedances that are relatively constant with signal level and frequency which makes it easy to predict how the circuit would work and design so that it's repeatable in the way it works. In a bass, the (passive) pickup is very reactive, ie signal levels and impedances vary with frequency and the volume control is usually wired as a variable series resistance so the impedances seen driving the passive tone network vary a LOT, making it impossible to give a predictable frequency response, so every time you got the mids set right, and you adjusted the volume control the tone would change enough that it would be a PITA to use. Next, passive pickups have low signal outputs, usually under 100mV, so adding in a circuit that drops 26dB means you're now down towards 5mV which is going to make it a real challenge to avoid serious hum or to get a decent signal to noise ratio, especially in a stage environment.
 
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#16
Dharmabass said:
The circuits used in amps have gain circuits that make up for the losses. When you have the controls set midpoint* the entire frequency range has a loss; for your typical Fender type circuit, it's between 22 and 26dB. When you "boost" with one of these controls all you are doing is making the circuit have less loss in that frequency range of the control, not any actual gain. When you cut, it's just more loss of level. The amplifier stage before and/or after the passive tone control makes up for the loss introduced to get your signal levels (at least) back up to where they were before.
Click to expand...

That's what I'm after. With the knob all the way up I want it to be flat or no loss, with it all the way down, I want it to have -15db cut. The tone control on passive instruments now is a treble rolloff. Basically doing the same thing at a higher frequency. All I want to do is set the center frequency at 800hz instead of 4k or whatever it usually is. Obviously you would want it to be a dip instead of a shelf type eq as well.
 
#18
Well, you could do a mid-cut with a passive control. Whether or not you like the result would be another story. As for Fender amps, they aren't passive. No amplifier is passive. The tone circuits do use passive components, but you have an active circuit controlling impedance before and after the mid control. You do not have this in a passive bass.
 
#19
I got a response from William Villex! I guess my email made it through afterall. here's what he had to say.

Hi Daniel,

*

Villex pickups are exactly what you describe. Our pickups have huge dynamic range. Bottom end can easy pick C# (check on 12 string Adler bass). Highs are not overwhelming but just give "air". Villex pickups have integrated passive magnetic circuit controlled by 50 K pot. Range is +7 db - 8 db. Frequency deviate between 750 - 820. As you cut it drops to 750 Hz and as you boost it will be around 820. Output is close to active basses. Extremely resistant to hum and buzz. Practically dead quite. I am sure you will love it!

Respectfully,

William Villex
 

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