4 pots for a passive!

kipsus · #1 07-21-2007, 11:38 AM

There are four knobs right now - blend, volume, bass, treble. I want to get rid of that crappy preamp and go full passive, at least till I get/build something better than Baxandall on a TL072..

Now, the question is, how to use the holes? Standard vol+vol+tone uses only three and leaving a dummy pot doesn't sound quite right

Any suggestions welcome

i_got_a_mohawk · #2 07-21-2007, 11:58 AM

Volume/Volume/Tone/Tone would surely be the simplest?

You can also add a passive low-pass ("tone" is hi-pass)

A9X · #3 07-21-2007, 01:01 PM

Quote:

Originally Posted by i_got_a_mohawk

("tone" is hi-pass)

A standard tone control is low pass.

i_got_a_mohawk · #4 07-21-2007, 01:04 PM

My bad, got it the wrong way around then

DavidRavenMoon · #5 07-21-2007, 01:20 PM

Quote:

Originally Posted by kipsus

at least till I get/build something better than Baxandall on a TL072..

I've made some great sounding preamps with that combination. What didn't you like about it? Maybe your EQ values are off.

You can do 2 volumes and 2 tones. 4 pots in parallel will make the bass a little darker.

ibanezcollector · #6 07-21-2007, 02:36 PM

1 volume, 1 tone, 1 3 way switch, 1 series/parallel switch

Like so.. but I added a input as well as a kill switch, my favorite bass now I wouldnt sell it for the world its so much better with out the preamp.

kipsus · #7 07-21-2007, 03:28 PM

Quote:

Originally Posted by DavidRavenMoon

I've made some great sounding preamps with that combination. What didn't you like about it? Maybe your EQ values are off.

You can do 2 volumes and 2 tones. 4 pots in parallel will make the bass a little darker.

Well the thing was definitely chewing up my tone. Removed it half an hour ago and well initial play tests suggest a tremendous improvement in clarity and richness. However I do not think this is due to TL072 or baxandall, it's probably caused by cheapo caps (I see a couple electrolytics and ceramics there) and or/poorly designed circuit. After all it used to be a cheap bass.
If I decide to make it active again, it'll be something like this:
http://www.albertkreuzer.com/preamp_onboard.htm

ibanezcollector: 3 way for bridge/neck/both selection? Sounds like a good idea, I mostly use blends 100/0% - 50/50% - 0/100%
Series/parallel isn't needed I guess because it's a P/J

DavidRavenMoon · #8 07-21-2007, 05:05 PM

Oh, this was the preamp in the bass already? Probably has too high an input impedance. There are some bad preamps out there. What kind of bass it is?

kipsus · #9 07-21-2007, 11:18 PM

Input impedance was sub 100k IIRC so I'm suspecting quite the opposite. And well the preamp was a bit boomy, I only used it to slightly boost the lows and to cut highs.

The bass is Vintage V940fl (http://www.jhs.co.uk/vintagebass.html) really low end stuff but only the hardware. The neck is not perfect but okay and the body is very well made. So I figured I change stuff on it and have an OK bass

DavidRavenMoon · #10 07-22-2007, 01:40 PM

Quote:

Originally Posted by kipsus

Input impedance was sub 100k IIRC so I'm suspecting quite the opposite. And well the preamp was a bit boomy, I only used it to slightly boost the lows and to cut highs.

That's too low. I think 1M is minimum for high impedance pickups, unless you want to load them down for a muddy tone. That's probably why it's boomy. The bass shelf frequency might be too low also. Surprising they would use a bifet op amp and then cripple it with a low input impedance.

Quote:

Originally Posted by kipsus

The bass is Vintage V940fl (http://www.jhs.co.uk/vintagebass.html) really low end stuff but only the hardware. The neck is not perfect but okay and the body is very well made. So I figured I change stuff on it and have an OK bass

Looks like you can make it into something good. I had a Hondo II P-bass copy someone gave me once. The bass was OK, but the hardware was crap. I changed all the hardware and electronics, and it was a great sounding bass.

nuno.ka · #11 07-22-2007, 02:37 PM

My passive Warwick is: Volume - Blend - Tone - Tone, and I like this combination, it's very versatile you can roll off the treble on the P and blend in a bit of J bite.

I'd love to try, Volume - Blend - Tone - Villex mid booster (all passive).

**Marcus Willett** · #12 07-22-2007, 03:20 PM

Quote:

Originally Posted by kipsus

the question is, how to use the holes? Standard vol+vol+tone uses only three and leaving a dummy pot doesn't sound quite right...Any suggestions welcome

Two ideas come to mind. One is use the extra hole for a series/parallel mini toggle. The other (better, IMO) idea is to add the HAS-SOUND midrange plus knob. Still passive but gives you nice midrange control.

Quote:

Originally Posted by nuno.ka

I'd love to try, Volume - Blend - Tone - Villex mid booster (all passive).

Even better. Got 3 basses with the Villex system and it's awesome. One has the tone booster too (not the mid booster)...still passive and tons of tone shaping.

kipsus · #13 07-23-2007, 12:55 AM

Quote:

Originally Posted by Marcus Willett

Two ideas come to mind. One is use the extra hole for a series/parallel mini toggle. The other (better, IMO) idea is to add the HAS-SOUND midrange plus knob. Still passive but gives you nice midrange control.

Even better. Got 3 basses with the Villex system and it's awesome. One has the tone booster too (not the mid booster)...still passive and tons of tone shaping.

Those "midrange controls" seem to be simple RCL combinations

midopa · #14 07-23-2007, 07:37 AM

What about something like vol, blend, tone, and a Vari-Tone sort of thing? Would that be a viable mod? I've been thinking about doing something like that for a while now.

funkybassplayer · #15 07-23-2007, 07:54 AM

www.guitarelectronics.com is the place to go. It is ablsolutely loaded with wiring diagrams swithches, pot, PUPs, pre's, and more. i have even just called these guys to answer some questions and they were a great amount of help.

**Marcus Willett** · #16 07-23-2007, 08:37 AM

Quote:

Originally Posted by kipsus

Those "midrange controls" seem to be simple RCL combinations

OK...so..? They work and sound good. Why should I (or the OP) care that it's a "simple RCL combination"

RBasss · #17 07-23-2007, 12:54 PM

Quote:

Originally Posted by kipsus

There are four knobs right now - blend, volume, bass, treble. I want to get rid of that crappy preamp and go full passive, at least till I get/build something better than Baxandall on a TL072..

Now, the question is, how to use the holes? Standard vol+vol+tone uses only three and leaving a dummy pot doesn't sound quite right

Any suggestions welcome

I'm in the same boat as you right now with a Heritage Classic Mockingbird I'm getting ready to pickup. I'm pretty sure I'm going to go Volume, Volume, Tone, 3-way switch, but this Villex mid booster seems intriguing.

kipsus · #18 07-23-2007, 01:07 PM

Quote:

Originally Posted by Marcus Willett

OK...so..? They work and sound good. Why should I (or the OP) care that it's a "simple RCL combination"

I didn't say it should sound bad because of that. After all, having that "L" in there already makes it a more sophisticated passive design than probably 90% (or more) of what is used.

Oh and it IS cool but not cheap either

**Marcus Willett** · #19 07-23-2007, 03:59 PM

Quote:

Originally Posted by kipsus

I didn't say it should sound bad because of that. After all, having that "L" in there already makes it a more sophisticated passive design than probably 90% (or more) of what is used.

Oh and it IS cool but not cheap either

You and I must have very different ideas as to what constitutes "cheap". A pretty slick passive midrange tone filter for $16.95 is pretty cheap where I come from.

Anyway, just a thought for the OP...