Electronics Nerds - I Need Your Help

[walterw]

OK, so we're definitely talking about isolating the two from each other with some sort of active combiner (otherwise any treble rolloff of the neck pickup would roll off the bridge, too.)

tobias used to make a bass called the growler that had a weird setup with one bartolini music man-style pickup but two preamps! each coil of the pickup was itself a humbucker, and each one had its own bass and treble active EQ. (they were then combined at a blend/pan knob and went to a single output.)

it was kinda goofy, since the two coils were next to each other, so boosting the bass on one sounded little different than doing it to the other one, but...

on something like you're talking about with two radically different pickups, i wonder if the effect would be more dramatic?

if you could get a hold of that bart preamp, you could really kill the highs and boost the lows on one pickup and do the opposite on the other, without them interacting with each other.

you'd also avoid the resonant mid-hump that happens when you just roll off a passive tone knob.

 

[Alex Xander]

Yes, the pickups will be isolated. We are almost on the same page here...

What Derek has designed is an active preamp with a 12db/oct crossover on each pickup. I'm familiar with the bart that you are talking about (the EZQ I think, bestbassgear has them), but they aren't quite what I'm chasing. This crossover will be fixed.

I'm optimistic about the outcome. The physics all makes good sense in my head

 

[EricssonB]

Would it be within your inventory of amps and effects to run both pickups with their own output jack and have its own signal chain?

 

[Alex Xander]

Would it be within your inventory of amps and effects to run both pickups with their own output jack and have its own signal chain?

Easily.

I want the ability to plug this thing into any amp (not just my rack gear) though, hence the idea of doing it onboard.

 

[EricssonB]

Easily.

I want the ability to plug this thing into any amp (not just my rack gear) though, hence the idea of doing it onboard.

Gotchya. I must be thinking from my perspective to split my signal about half-way between the amp and bass.

 

[SGD Lutherie]

If it's a real mudbucker, there's really no need to remove the treble, as there isn't any. You can try a few different caps with the bridge pickup. .0047µF will remove all the low end. But depending on how much mids you need, you might have to go larger.

 

[Alex Xander]

If it's a real mudbucker, there's really no need to remove the treble, as there isn't any. You can try a few different caps with the bridge pickup. .0047µF will remove all the low end. But depending on how much mids you need, you might have to go larger.

I was initially considering this approach, but there would inevitably be either a frequency gap or overlap, which I want to avoid due to phase cancellations. In chasing a neat and concise cutoff between the two pickups, not a "she'll be right" approach.

The circuit Derek has designed is crossed over at 234Hz (which will just catch the second harmonic of the A on the G string). A mudbucker us still doing plenty above that frequency, so I can't just leave it as is.

 

[SGD Lutherie]

(which will just catch the second harmonic of the A on the G string).

An active crossover is the way to go, and I actually designed a system like this once, realizing that it's sometimes useful to not have the pickups over lap. On the other hand, I often use just the neck or bridge pickup, so I would want the full range response from either of those. A bright neck pickup is a tonally different tone from the high end coming from the bridge pickup. And sometimes the over lap is what you want. They all sound different.

However, it wont be the second harmonic of the A on the G string when you fret a note. And why wouldn't it be the same I'd forget that whole harmonic thing. Just tune it by ear.

The mudbucker doesn't have much in the way of midrange, so you want to cross over pretty low. The other thing with this is that the characteristic tone of the mudbucker will be missing, because you are eliminating the resonant peak. because you are using filters, you can use a regular wound neck pickup, or even better, low Z pickups for a more lows and highs. Having more frequencies to start with is better. I'd also make the break point adjustable. ;0

 

[Alex Xander]

An active crossover is the way to go, and I actually designed a system like this once, realizing that it's sometimes useful to not have the pickups over lap. On the other hand, I often use just the neck or bridge pickup, so I would want the full range response from either of those. A bright neck pickup is a tonally different tone from the high end coming from the bridge pickup. And sometimes the over lap is what you want. They all sound different.

However, it wont be the second harmonic of the A on the G string when you fret a note. And why wouldn't it be the same I'd forget that whole harmonic thing. Just tune it by ear.

The mudbucker doesn't have much in the way of midrange, so you want to cross over pretty low. The other thing with this is that the characteristic tone of the mudbucker will be missing, because you are eliminating the resonant peak. because you are using filters, you can use a regular wound neck pickup, or even better, low Z pickups for a more lows and highs. Having more frequencies to start with is better. I'd also make the break point adjustable. ;0

For this to be done easy and experimentally, I needed to pick a crossover frequency. I wanted to get the second harmonic of the meat and potatoes notes from the neck. The second harmonic if the A on the G string is 220hz, so I will get it.

Tuning by ear would be a nice luxury, but since I am not doing the electronics side of things, I can't do that. I can do it on the amp end though.

 

[walterw]

The other thing with this is that the characteristic tone of the mudbucker will be missing, because you are eliminating the resonant peak.

oh hey, i didn't think of that; crossed over like this, all of the "personality" of the mudbucker gets low-passed away.

with that in mind, i'd expect the result to just sound like the bridge pickup but with a bass boost.

 

[Alex Xander]

oh hey, i didn't think of that; crossed over like this, all of the "personality" of the mudbucker gets low-passed away.

My empirical evidence suggests otherwise...

I've tinkered quite a lot with this and outboard equipment. This is a Dimarzio Model One (tonally very similar to the Gibson it replaced). The bridge pickup is still the standard Gibson mini-humbucker, it's highs are better than the neck pickup, but still far from what I would call a bright pickup. I have done a rough "proof of concept" using rack gear or my line 6 stuff

I'm not taking a total crapshoot here lads


Link Removed

 

[Timm]

Sorry for reviving an old thread, I was just curious how the experiment turned out?

I'm considering doing something similar to my Yamaha attitude.