Would this layout work?

[doran.dragic]

Hello everyone,

I'm in the process of planning the pickups and electronics layout for my custom bass. The bass will feature:
- 2 MAMA Special Quad pickups (each of the 2 pickups comes with a 5 way rotary switch for parallel / series / front coils / rear coils).
- 3 band active preamp with mid selection and active / passive.

The problem is the number of knobs. Since each of the 2 pickups comes with a 5 way rotary selector there's going to be a lot of knobs and I'm trying to minimise the number by using stacked potentiometers.

I came up with a layout solution, but I'm not sure if it is going to work:

Pot 1: stacked + push-pull
Volume + balance + active / passive on the push-pull

Pot 2: stacked
Bass boost / cut + High boost / cut

Pot 3: stacked + push-pull
Mid boost / cut + Passive tone + Mid frequency selector on the push-pull

Pot 4: 5 way rotary switch series / parallel / front / rear / split coil

Pot 5: 5 way rotary switch series / parallel / front / rear / split coil

MEC makes stacked push-pull pickups but I don't know if they can be used in a way I want them to do. Did anybody have experience with these potentiometers or maybe any other comments on this layout?
Potentiometer

 

[MidlifeBeginner]

With that pickup configuration, I would recommend buying a preamp with active blend (two pickup inputs) and not have a passive mode. If you have the pickups in different coil mode from each other, output can be vastly different. An active blend can handle that better than a passive blend.

 

[MidlifeBeginner]

I think an example would be a Nordstrand 3B-4B. That is 4 knobs in addition to the two rotary switches. You could always contact their customer support to hear what their recommendation would be.

 

[Hundred proof]

Interesting project, I greatly simplified my similar concept by using 2 separate discrete preamps for each half of the single Nordstrand quad coil pickup. Front half and back half with a single blade switch. Stacked treble/bass with individual volume for each half, the preamps are Audere Classic series powered by a single 9 volt battery.

 

[ctmullins]

That is way too many options. I predict that once you get that maze of wiring all connected and working, you’re going to use maybe four of the 250 possible tones available.

 

[Jazz Ad]

Indeed. On a custom bass you want all the options you need and only that. It's worth taking time with the instrument to know what works for you and ditch the rest.
What you want can be done it's just going to be impractical at best. You don't have presets and no way to find back a specific tone.
The multiple witing options over 2 pickups will lead to phase issues in some positions and loss of humbucking effect quite often.

 

[Keither]

Yes,
the push pull stack knobs can be wired like that.

It isn't uncommon for guitars to have all the switching options imaginable on rotary.
Legal or not nobody even calls the police on Alembic...
You can always simply the switching later if you'd like to put all of us at ease (please).

 

[jj.833]

I think this scheme will work nicely. You definitely want the mid button on active preamp; I use Audere with stacked lo mid-hi mid, and feel no need to adjust the mid frequency. Seems to me easier to use than stacked mid freq-mid volume, and way more practical than fixed frequency switch.

The biggest issue with active knobs is that you need them to be easily practical; if there's a need to be very careful with performing every adjustment, you will not use the knobs. Two tips:

Three or four of my students used Sire jazz basses; there's quite intricate preamp, see attached. They usualy have problems with the passive tone - it's easy to forget its proper position, sometimes they keep if rolled off for weeks, wondering why the bass sounds so dull. I was always wondering why such a confusing knob, as not a single one of my students ever preferred the passive tone to active EQ. I guess the answer comes from Sire's PR department. If you really need the passive tone, perhaps there's a way to wire it together with another knob (in active mode it controls, say, mids; in passive it is tone; in active the tone don't work)

I'd also think about the passive push-pull: the knobs you will use most will be volume and balance; you want these to be as handy as possible, without the need to be really careful when touching them. Perhaps the little switching lever (which is also very cheap) as on this Sire preamp might work better.

 

[sikamikanico]

I checked out the MAMA website, they do have an option for a simple 3-way switch that should give you the key options, which you can then tailor with the preamp. The 5-way rotary switch would be interesting for a passive bass, tho even there I don’t know if you’d hear much difference between the P and the J options + series probably sounds too thick.

Since im not an active bass user, I cannot comment on what layout is most practical, but I found stacked knobs cumbersome in the past unless you’re the “set it and forget it” type.

 

[doran.dragic]

With that pickup configuration, I would recommend buying a preamp with active blend (two pickup inputs) and not have a passive mode. If you have the pickups in different coil mode from each other, output can be vastly different. An active blend can handle that better than a passive blend.

Terrific, this is something I haven't considered, thanks. I think I'll discuss this with MAMA first to see what their opinion is on that topic and go from there.

That is way too many options. I predict that once you get that maze of wiring all connected and working, you’re going to use maybe four of the 250 possible tones available.

Indeed. On a custom bass you want all the options you need and only that. It's worth taking time with the instrument to know what works for you and ditch the rest.
What you want can be done it's just going to be impractical at best. You don't have presets and no way to find back a specific tone.
The multiple witing options over 2 pickups will lead to phase issues in some positions and loss of humbucking effect quite often.

Yes, I'd expect for some of this options to not be really useful. But it's hard to know which those are without trying it out first. I was hoping that this pickup combination would give me the P, the J and the MM sound in the same bass.

True, the bass doesn't have presets but I have a Line 6 Stomp on most of the gigs and it would be easy to make presets that match the gain of the pickup combinations that I use the most and the EQ that need. I do this now anyway on my current bass since my neck pickup is much louder than my bridge pickup.

The onboard preamp will only be used in situations where I don't have a pedalboard but would want to have some control over the sound of my bass (in most of my gigs I don't use any amplifier so I don't use the EQ).

I didn't realise that phase issues and loss of humbucking effect might happen. Is there any way to know, which of the combinations would be more prone to these issues?

I think this scheme will work nicely. You definitely want the mid button on active preamp; I use Audere with stacked lo mid-hi mid, and feel no need to adjust the mid frequency. Seems to me easier to use than stacked mid freq-mid volume, and way more practical than fixed frequency switch.

The biggest issue with active knobs is that you need them to be easily practical; if there's a need to be very careful with performing every adjustment, you will not use the knobs. Two tips:

Three or four of my students used Sire jazz basses; there's quite intricate preamp, see attached. They usualy have problems with the passive tone - it's easy to forget its proper position, sometimes they keep if rolled off for weeks, wondering why the bass sounds so dull. I was always wondering why such a confusing knob, as not a single one of my students ever preferred the passive tone to active EQ. I guess the answer comes from Sire's PR department. If you really need the passive tone, perhaps there's a way to wire it together with another knob (in active mode it controls, say, mids; in passive it is tone; in active the tone don't work)

I'd also think about the passive push-pull: the knobs you will use most will be volume and balance; you want these to be as handy as possible, without the need to be really careful when touching them. Perhaps the little switching lever (which is also very cheap) as on this Sire preamp might work better.

Terrific information, thanks. I guess I wasn't clear enough about how the mids would be wired or maybe didn't understand your post fully. If I understand correctly the preamp in question (MAMA 3 band) only has 2 fixed bands of mids that can be either boosted or cut and you can only choose one of them at the time. So this is why I wanted to put them on a stacked pull-push switch. The push-pull action would allow me to choose one of the 2 bands which I then either cut or boost and the other part of the pot could be used as a tone control.

Also great tip on the volume and balance knobs.

The passive tone control isn't the priority but it's a good thing to have in case it's one of those gigs that I do without the pedalboard and the battery dies.

I checked out the MAMA website, they do have an option for a simple 3-way switch that should give you the key options, which you can then tailor with the preamp. The 5-way rotary switch would be interesting for a passive bass, tho even there I don’t know if you’d hear much difference between the P and the J options + series probably sounds too thick.

Since im not an active bass user, I cannot comment on what layout is most practical, but I found stacked knobs cumbersome in the past unless you’re the “set it and forget it” type.

Just for my understanding: the reason for P and J sounding similar is that the J pickup is not a single coil in this case and the distance between the 2 coils not great enough to actually matter?

 

[ctmullins]

There is no single P sound.

There is no single J sound.

There is no single MM sound.

So the best you can do is an approximation of each of those. And that’s achievable with a much simpler circuit than what you’re proposing.

Look, I understand the appeal of a “Swiss Army knife” bass. I was right there with you twenty years ago. But after tinkering a lot, my personal experience is that less is more here.

 

[doran.dragic]

There is no single P sound.

There is no single J sound.

There is no single MM sound.

So the best you can do is an approximation of each of those. And that’s achievable with a much simpler circuit than what you’re proposing.

Look, I understand the appeal of a “Swiss Army knife” bass. I was right there with you twenty years ago. But after tinkering a lot, my personal experience is that less is more here.

What would be your suggestion?

 

[MidlifeBeginner]

The onboard preamp will only be used in situations where I don't have a pedalboard but would want to have some control over the sound of my bass

My recommendation is to just wire the bass passive. For the rare situation that you won't take your Line 6, buy a Zoom B1Four. It is a relatively cheap, small backup for your Line 6. With all the options available with that bass wired passive, you might find you can do a gig fine without touching active EQ.

The alternative is just wire it active, and throw a new spare battery into your gig bag once a year.

 

[sikamikanico]

Just for my understanding: the reason for P and J sounding similar is that the J pickup is not a single coil in this case and the distance between the 2 coils not great enough to actually matter?

yup, basically. Regular J neck vs P sound already sound very similar, and it’s more similar in a Quad pickup. Even neck vs bridge coil is not that different on their own, but the differences are emphasized when you have two pickups. Like setting 2 vs 4 on Musicman HH Stingray (outer coils vs inner coils), that’s a noticeable difference. Yet both kinda sound like a version of the jazz bass.

 

[ctmullins]

What would be your suggestion?

Well, first of all, I apologize if I'm coming off as negative, and raining on your parade.

But since you asked - my preference is no more than a series/single switch for each pickup, paired with a two-band active EQ. A battery box makes a passive switch unnecessary. For me.

But it sounds like you're already committed to these particular pickups? And they already come with the rotary switches? In that case I would skip the onboard active circuit entirely, as @MidlifeBeginner suggests above, and just go full passive. I wouldn't even need a tone control, but that's just my personal preference.

If this helps, I have three basses that each have three pickups, with a six-position switch and a master volume. That alone is enough tonal variation to meet all of my needs. Six switch positions means quick and repeatable tones in a live environment.

 

[doran.dragic]

Well, first of all, I apologize if I'm coming off as negative, and raining on your parade.

But since you asked - my preference is no more than a series/single switch for each pickup, paired with a two-band active EQ. A battery box makes a passive switch unnecessary. For me.

But it sounds like you're already committed to these particular pickups? And they already come with the rotary switches? In that case I would skip the onboard active circuit entirely, as @MidlifeBeginner suggests above, and just go full passive. I wouldn't even need a tone control, but that's just my personal preference.

If this helps, I have three basses that each have three pickups, with a six-position switch and a master volume. That alone is enough tonal variation to meet all of my needs. Six switch positions means quick and repeatable tones in a live environment.

No problem at all, I really meant it when I said it that any input or concern is appreciated.

Why does a battery box make a passive switch unnecessary for you? Wouldn't you want an option of having a backup plan if you don't carry a spare battery?

And in all honesty, something like a switch might work better for me as well since I think I'll be either using one of the two pickups or both together. So this is a great idea and something that I haven't even considered.

About my commitment to these pickups: I mostly chose them because they've been designed exactly for this purpose and I thought that installing them won't be a problem. I'm not 100% sure on those yet - mostly because there are no sound samples. All I could find was a positive review on Reddit. I'd be willing to consider other alternatives.

But the fact that they come from the European Union plays a significant role because I don't have to pay extra money for expensive shipping, customs and import tax.

Another important factor, maybe the most important, is the EMG shape of the pickup. I strongly dislike the feeling of the mounting tabs on the standard MM 4 string pickups. And in case that I hate the way the bass sounds they'd be easy to replace.

 

[ctmullins]

I always carry a spare battery. Usually always two of them.

And I've never once felt that the passive tone was better than the active tone.

So for me it's full-active all the time, and a battery box with spare batteries is my insurance.

(Oh - and a spare bass too! )