M5V Pickup Swap (w/ Shielding Lesson!)

[RocketMusic]

After recently receiving this Mike Lull M5V with single coils, I was convinced that I need to try single coils in one of my basses. I've been paranoid for years about noise, but I finally decided that the tonal improvements might be worth a little extra effort in the shielding department (and maybe still having to live with a little more noise than usual in some environments).

I already had a set of Nordstrand NJ5 single coils pickups in stock. Since they fit in my Lull and not King Koa, my Lull M5V got to be the guinea pig.



Here's tip #1: not all 5-string J pickups are the same size!! There are two fairly common variants: the NJ5's are the shorter variant, and the neck and bridge pickups are the same size. Mike Lull uses this size on most (all?) of his 5-string J & PJ basses. The other variant is usually called something with "Fender" in the name. These types (Nordstrand NJ5FS, for example) are longer, and the bridge pickup is even longer than the neck pickup.

Here's what the NJ5's looked like right out of the box. These are upside down, so you're looking at the bottoms of the pickups.



Notice anything strange? If you do enough pickup swapping with pole-based pickups, you get used to seeing the poles grounded/shielded together. These pickups don't come that way. It won't necessarily cause a problem, but if it does it would likely be that you get some crackling when your fingers touch the exposed pole pieces. It's easy enough to cure with some copper foil tape. I could have just taped over the pickups black ground to make the connection, but I don't trust the adhesive to stick forever. So I added a wire from the copper foil to the existing black wire on the pickup. CAUTION: heat can de-magnetize alnico magnets, so solder the wire to the tape BEFORE you stick the tape on.



The last thing I'll do to the pickups is add a wider strip of tape to shield the entire back of the pickup, and I'll add a wire than I can use later to connect all of this pickup shielding to the pickup cavity's shielding.



Tip #2 - the adhesive on the back of most copper foil is conductive. If you lay one piece of tape across another, they will be shorted together.

OK, that's all we have to do to the pickups, they're ready to be installed. But first, in the next post, I'll add some shielding to the pickup cavities.

[RocketMusic]

The next step was to remove the existing pickups. I de-soldered them from their connections in the control cavity, and then I pulled them out:



Mike Lull uses conductive paint to shield the pickup cavites and the control cavity. He also sprays the paint on the control cavity cover. Conductive paint is certainly good, and it's what you usually see in a production sort of environment. When I'm doing stuff to my own basses, though, I like to break out the copper foil.

So next I scraped out the self-adhesive foam in the pickup cavities, and then I laid in a nice layer of copper foil on the bottom and sides of the pickup cavities. I also ran a wire from the pickup cavity shielding into the control cavity. Later, I'll ground that wire in the control cavity so that all of the shielding (back of PUP, PUP cavities & control cavity) are all tied/grounded together. Hopefuly that's up to Vroom-Vroom's CDO standards. It's certainly as neat a job as I've ever done.



Lastly, I attached the ground wire from the pickup's shielding to the shielding in the pickup cavity.



After that I installed some new foam in the pickup cavities, ran the pickup wires into the control cavity, and finally installed the pickups in the pickup cavities. So at this point, the pickup magnets, the pickup common wires, the shielding on the back of the pickups and the shielding in the pickup cavities are all shorted together.

Next up - I'll work on the control cavity shielding a little bit and make the final connections!

[RocketMusic]

As I mentioned earlier, Mike sprays the inside of the control cavity cover with conductive paint (that's the gray stuff you see in the photo below).



That's all well and good, but I decided to cover it with copper foil. I'm the Anal Retentive Electrical Engineer!! I'll have to make sure I wrap my garbage in a little baggie that I put inside a second baggie.

Mike has a nice metal ground hook in the control cavity. I ran a piece of tape to that, and then I ran the tape up over the lip of the control cavity. The tape on the cover should hit that piece of tape, and once again all the shielding gets shorted to ground.

My next project will be yanking out the Bart NTMB and installing an Aguilar OBP-1 preamp. For that reason, I didn't bother shielding the control cavity any further just yet. I'll do some more foil taping in there when I get around to that part of the project.



The last thing I did today was make the final connections in the control cavity & put the bass back together with strings (still TI jazz flats).

I recorded BEFORE and AFTER clips, and I'll post those next!

[RocketMusic]

Before I started tearing things apart this morning, I first recorded the bass with the original Seymour Duncan Hum-Cancelling pickups that were in the bass. These are custom wound for Mike Lull, and as you will soon hear... they sound pretty darn good compared to real single coils.

Here's a clip with the Duncan HC's:
"M5V Demo Clip" (Duncan HC's & Bartolini NTMB)

Here's the same clip with the Nordstrand NJ5 single coils:
"M5V Demo Clip" (Nordstrand NJ5's & Bartolini NTMB)

In both clips, the chords were played with the bridge PUP solo'd and the bassline was played with both pickups blended equally. I didn't change any of the EQ/compression/panning/etc in my DAW. Everything is presented as apples-to-apples as I could make it.

I hear the Duncans sounding a little fatter, warmer and darker. The single coils are brighter and more articulate to my ears. So far I think I prefer the single coils, but we'll see how I get on with any noise situations down the road. Let me know what you think! Hopefully, I'm not just pissing in the wind.

[Darkstrike]

Nice, detailed work, a lot more exhaustive than I've ever gone when shielding.

[RocketMusic]

One more fun fact. You can access larger/higher resolution versions of all of these photos by appending "-HI-RES" to the file name. For instance, if the linked photo is called:

"http://www.rocketmusic.net/images/SHIELDING-EXPLAINED-NJ5S-IN-BOX.jpg"

then try downloading this to see a much larger image:

"http://www.rocketmusic.net/images/SHIELDING-EXPLAINED-NJ5S-IN-BOX-HI-RES.jpg"

[RocketMusic]

Originally Posted by Darkstrike

Nice, detailed work, a lot more exhaustive than I've ever gone when shielding.

Yeah, it's a bit overkill, but I've done enough pickups installs now that I'm sick of getting everything done only to find a little buzz and then having to go back to the bench and take stuff apart again. Bleah! Get it right the first time is my new motto. Over engineer and get rid of all that noise.

[RocketMusic]

Also - here are a couple of fantastic articles from Audere Audio that are good reference material!

The first article talks about grounding pickup pole pieces. Just keep in mind that some of what he talks about is only necessary when you have a floating ground (which most preamps don't, but Audere does). You can just take the pickup magnet shielding straight to ground for the Bartolini and Aguilar preamps.

The second article is about shielding pickups and pickup cavities, and really WHY you need to do it. It's a GREAT article if it doesn't go over your head.

[Darkstrike]

Originally Posted by RocketMusic

Yeah, it's a bit overkill, but I've done enough pickups installs now that I'm sick of getting everything done only to find a little buzz and then having to go back to the bench and take stuff apart again. Bleah! Get it right the first time is my new motto. Over engineer and get rid of all that noise.

Oh, don't get me wrong, I applaud you, it's definitely the better approach.

FWIW, I've always found shielded single coils to be quiet enough, or humbuckers switched to single coil.

Might even swap the humbuckers in my Roscoe J to singles, to get a 100% classic J vibe in passive mode.

[VroomVroom]

You only use two baggies?

Beautiful work, Cochise.

FWIW. I've got the Duncan humcancelling pickups in my alder/rosewood M5V, and that bass sounds 100% like a 60's Fender J to me. Fortunately it doesn't play like one.

If you don't mind sharing, I'm actually more curious about the, "why" behind the OBP-1.

[RocketMusic]

Originally Posted by VroomVroom

You only use two baggies?

Beautiful work, Cochise.

FWIW. I've got the Duncan humcancelling pickups in my alder/rosewood M5V, and that bass sounds 100% like a 60's Fender J to me. Fortunately it doesn't play like one.

If you don't mind sharing, I'm actually more curious about the, "why" behind the OBP-1.

I had the chance to play Jeff Moote's Roscoe PJ that has Aguilar pickups and an OBP-1 preamp. Whoa! That's a killer bass. What I really dig about the OBP-1 is it does very little to the tone when neither boost control is boosted. With everything down, it basically sounds passive. So you essentially have a passive sounding bass with the option of some bass and/or treble boost. Stick a passive tone control in front of the preamp so you can roll off some highs, and it's fully functional. The treble on the OBP-1 is really sweet sounding, too.

[Darkstrike]

Originally Posted by RocketMusic

I had the chance to play Jeff Moote's Roscoe PJ that has Aguilar pickups and an OBP-1 preamp. Whoa! That's a killer bass. What I really dig about the OBP-1 is it does very little to the tone when neither boost control is boosted. With everything down, it basically sounds passive. So you essentially have a passive sounding bass with the option of some bass and/or treble boost. Stick a passive tone control in front of the preamp so you can roll off some highs, and it's fully functional. The treble on the OBP-1 is really sweet sounding, too.

That does sound like a gorgeous pre-amp setup, how would you compare it to the OBP-3?

[Jeff Moote]

I have both the OBP-3 and OBP-1, though in different basses with different woods/pickups. My take is that set flat they sound the same. Start boosting and cutting and the differences come out. Besides the mid band on the -3, the boost/cut on the treble and bass have a different characteristic than the boost only bands on the -1 and certainly a different vibe when actively cutting treble vs. the passive tone roll off.

Both are totally valid approaches and have their place, but for me the -1 and passive tone does it, especially when you want a more vintage sound with a bit of active edge in a J/J or P/J bass. The 3 band preamps from Aguilar, Bartolini, etc. seem more at home in more modern sounding basses IME/IMO.

As for the Lull experiment above - well I definitely dig both sounds! I played it with the Duncans and they rock, but in a not-so-vintage J-bass sounding kind of way. They almost do their own thing to me, which is great but the NJ5s nail the vintage vibe better and swapping out the NTMB should complete that thought.

[RocketMusic]

The treble boost on the OBP-1 starts at 4kHz, while the treble boost/cut on the OBP-3 starts at 6.5kHz. The 6.5 kHz is pretty darn high, that's getting into "air" range (you'll often hear folks suggest that you add 6-7kHz to make something sound more airy). The 4kHz is more in the meat of the upper end of a bass's tone.

[Darkstrike]

Sounds like I need to order myself an OBP-1, some control knobs and stuff, rewire my Gadow once more, and see for myself.

Forgot about the soundclips, sorry, just listening through my speakers at the moment, and to be both sound great, but I slightly prefer the single coils, a touch more lively to me.

[RocketMusic]

The only trick with the OBP-1 is the tone pots: they need to be 25K audio taper with no center detent. Aguilar provides two separate pots with the OBP-1, but if you need to stack because of having just 4-holes (say you want vol, vol, passive tone, and then stacked treble boost & bass boost) then you've got to hunt a bit.

EMG sells such a pot with solder lugs, and they're the only source I've been able to find.

[VroomVroom]

Ok, at the risk of getting into gossipy stuff (shhhhhh), how does Sadowsky do this, do you know? Their layout is just as you described. Would Aguilar be willing to customize something for you, do you think?

Total FYI thing, but I've struggled with every Sadowsky J bass I've played/owned (boy howdy, there've been a few), so I'm anxious to hear your thoughts, especially in a live mix. I've found that the tone either cuts too much or not enough, and it's very difficult to dial in the right happy spot. My Lulls, on the other hand...

FWIW, here's from a recent trio hit (with an amazing pianist visiting from the UK). Lull M5V, alder/rosewood, Duncan hum-frees, Bart NTMB, bridge pickup biased, totally flat EQ. Steamer - flat, but with the low EQ @ 10 o'clock, and Berg HT112ER.

The Chicken

[RocketMusic]

I grabbed 5 of EMG's stacked pots, and I'm guessing that will be a lifetime supply for me...

[Darkstrike]

Originally Posted by RocketMusic

The only trick with the OBP-1 is the tone pots: they need to be 25K audio taper with no center detent. Aguilar provides two separate pots with the OBP-1, but if you need to stack because of having just 4-holes (say you want vol, vol, passive tone, and then stacked treble boost & bass boost) then you've got to hunt a bit.

EMG sells such a pot with solder lugs, and they're the only source I've been able to find.

In my case it's one pickup, so Vol/Tone/EQ, I'd not have a probem with stack Vol-Tone/Bass/Treble if it came down to it though.

Cheers for the EMG ref. though, stacked EQ would be the tidiest, I think, and my preference.

Funny you mention the Sadowsky, Jerry, IIRC, I've heard before that the OBP-1 and Sadowsky pre are very closely voiced.

[RocketMusic]

Man! Nice groove on "The Chicken"! I'm listening on laptop speakers tonight, so I can't really speak to the tone... but who cares?!? It feels good!