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Simple Passive Bass cut

#4
I thiiiink that will be accomplished if you wire the cap and the pot in parallel. That way the cap always sends 100% of it's bass cut signal, or "wet", and then you adjust how much "dry" setting goes through with the pot. So with the pot fully opened, the entire signal is passed: turn the pot and less "dry" is sent, resulting in a bass cut.

This is all completely theory, I have never tried this or read about it anywhere.
 
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#8
Anyone else have much experience with bass cut conrols? It is my new favorite mod. Have done it on my Franken-J (Vol, Vol, Treble Cut, Bass Cut) and on a Strat.

Still experimenting with cap values but using 10% of the hi cut value seems to work pretty good (eg: .033 in parallel for treble cut and .0033 in series for bass cut).

Am getting ready now wire do my Franken-P the same way along with adding a MM pickup at the bridge (currently has a P in the sweet spot and a mudbucker at the far-neck).

The thought occurs to me that with bass and treble cut controls it might be smart to use a scooped pickup like an SPB-3 Quarter Pounder in the middle.

I have a Dimarzio Willpower Middle in it now and am not sure whether to leave it or put the QP back in after I add the MM bridge pickup and passive tone controls. Probably will try both.

I may end up going with looks over tone if its a toss up - kinda like the look of those big polepieces with the black on black body.

Any suggestions on cap values or wiring would be of interest. Was planning to have one volume for the MM bridge p/u and one for the P and the Sidewinder with a 3 way switch between the two.

If anyone knows what a fair price for doing the MM bridge route I'd be interested. I'm going to hire it out since there is no pg to cover screwups.
 
#10
walterw said:
when would you ever want a bass cut on a bass, especially a passive J?
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When you want the bass boosted for some tunes and less so on others with out having to go to the amp. Leave the amp boosted and control it on the guitar. Same way I use the Low control on my on board preamp basses. There may be no time between tunes and it's easier to dial in while playing if the initial adjustment isn't quite right.

mech
 
#11
walterw said:
when would you ever want a bass cut on a bass, especially a passive J?
Click to expand...

In addition to what mech said, both of the basses in question have far-neck mudbuckers and the bass cut makes it more useful.

I'm not certain but think G&L uses a similar arrangement on the L-2000 Tribute which has passive tone controls. With passive tones you can only cut - not boost, but as mech said, you can effectively make it a boost/cut by changing amp settings or by using pickups which are bass-heavy.
 
#13
Oh and also just to have control over the bass band, by turning the bass up at the amp and then blending to taste with a potentiometer. With a passive bass, you have some useful control over the treble, but none with the bass, if that makes sense (using the onboard knobs). That's what I was going for at the time.
 
#14
raymondl3 said:
It's been a while, but I think my original purpose for it was to "boost" the mids and highs for solos.
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Unfortunately, a passive bass control would not boost mid or high volume when in the cut position and there will be and overall loss of volume due to the roll off of the lows. May work in some situations where other instruments laid back during whatever it was you wanted to do. Although you could cut the lows and raise the volume with the volume control if time permits.

One solution may to use a dual pot where one section would be used as the low cut and the other used to raise the volume. The sections would have to be opposite tapers so the volume would be raised as the lows were cut. The overall volume on the bass would be attenuated with the control in the non-low cut position and gain would need to be added at the amp. I have no idea as to what taper or value would need to be used for the volume control section. Maybe wired in series as a rheostat?

mech
 
#15
Doner Designs said:
I'm not certain but think G&L uses a similar arrangement on the L-2000...
Click to expand...

Yep. Just a 1M pot and a .0022µF cap. They specify a reverse log taper (C), but linear will work fine.
.
 

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#16
mech said:
When you want the bass boosted for some tunes and less so on others with out having to go to the amp. Leave the amp boosted and control it on the guitar.
Click to expand...
Doner Designs said:
In addition to what mech said, both of the basses in question have far-neck mudbuckers and the bass cut makes it more useful.
Click to expand...
OK, i'll allow it :D
 
#17
mech said:
Unfortunately, a passive bass control would not boost mid or high volume when in the cut position and there will be and overall loss of volume due to the roll off of the lows. May work in some situations where other instruments laid back during whatever it was you wanted to do. Although you could cut the lows and raise the volume with the volume control if time permits.

One solution may to use a dual pot where one section would be used as the low cut and the other used to raise the volume. The sections would have to be opposite tapers so the volume would be raised as the lows were cut. The overall volume on the bass would be attenuated with the control in the non-low cut position and gain would need to be added at the amp. I have no idea as to what taper or value would need to be used for the volume control section. Maybe wired in series as a rheostat?

mech
Click to expand...

Yes I realize this, that's why I put "boost" in quotes. When you cut the bass, you carve out more room for the mids and highs to be heard. That's what I was wanting for solos, instead of actually boosting. BTW nice idea about the dual pot configuration.
 
#18
raymondl3 said:
Yes I realize this, that's why I put "boost" in quotes. When you cut the bass, you carve out more room for the mids and highs to be heard. That's what I was wanting for solos, instead of actually boosting. BTW nice idea about the dual pot configuration.
Click to expand...

I've used the dual pot thing in distortion circuits for guitar pedals. As the level of gain was raised to increase distortion the lows were rolled off to get rid of the mud. I've also used it with different values for clean onboard preamps for acoustic guitars for the same reason. Like I said, I have no idea of the values or tapers needed to give a useful and pleasing effect for a bass. It would take some experimentation.

mech
 
#19
mech said:
I've used the dual pot thing in distortion circuits for guitar pedals. As the level of gain was raised to increase distortion the lows were rolled off to get rid of the mud. I've also used it with different values for clean onboard preamps for acoustic guitars for the same reason. Like I said, I have no idea of the values or tapers needed to give a useful and pleasing effect for a bass. It would take some experimentation.

mech
Click to expand...

I'm guessing a taper around 100HZ would be good, but since a passive roll off is fewer db/octave I wonder if it might be better to start it higher, like around 250?
 

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