DiMarzio Model J DP123

[LawrenceH]

I was surprised to see that there were no reviews of the Model Js already posted on here. There are plenty of reviews out there already, but I thought it might be worth doing one focusing on the wiring/passive electronics side of things. There is a techy bit in the middle for those that like that...

I recently installed these in an ash CIJ 75RI with maple fretboard. Previously this bass was ok but despite the alleged US pickups the tone somehow lacked authority across the spectrum, with neither the solid bottom nor the aggressive growl and upper-mid clank of a really good jazz bass. Swapping the originals with some MIM 'vintage' alnicos as used in the HWY1 and 'Classic' series improved things somewhat (I think these are great trad-sounding pickups), but I still felt it was a little lacking compared to the snappy acoustic tone of the bass. Throughout all the changes, the strings remained the same rather ancient (2 years now?) DR Black Beauties. Not the toppiest string to start with and now very very worn. I much prefer old strings when auditioning basses, makes it easier to judge the contribution of the bass/pickups etc.

I went for the 'creme' option, the adjustable matte-black pole pieces make this extra retro snazzy, or a horrendous eyesore, depending on your taste. As other users have noted, the large ceramic magnets on the base of these pickups make them stand a good deal taller than alnico equivalents. At first I was worried they wouldn't fit at all, but after removing the Fender pickup foam and replacing this with a thin sliver of the foam the DiMarzios were supplied in (as recommended in the installation instructions) they dropped in just far enough to allow me room to adjust the height to taste.


The DiMarzios are split-coil 4-wire pickups, allowing you the option of series or parallel wiring each pickup [i]separately[/i]. This is different from the jazz 'S1 mod' where a [i]pair[/i] of pickups are giving series/parallel wiring between them. I initially chose parallel wiring, and the tone of the bass was far more 'solid' with more bottom end and low-mids in particular. However, I still wasn't completely satisfied as I like that jazz top-end bite, so last week I set about making more mods.

Before going any further, here is a link to a very good explanation of how pickups shape tone (mainly focusing on the high end) and how the different electronics options interact with this: [url="http://buildyourguitar.com/resources/lemme/"]http://buildyourguit...esources/lemme/[/url]
The take-home messages in relation to this review are:
-That [b]pickups have a resonant peak before cut-off[/b], ie they emphasise characteristic frequencies in the upper-mid/treble range.
-Pickup inductance determines the frequency/Q of the peak. You can adjust the [b]frequency[/b] [b]downward[/b] by increasing capacitive load or by [b]switching the wiring from parallel to series[/b]. This latter will [b]halve[/b] the resonant frequency of the pickup as well as boost overall output.
-Adjusting the resistive load by changing [b]pot values[/b] alters the [b]height[/b] of the peak (Q).

DiMarzio's 'standard' wiring, as far as I can tell, is series, and their standard recommended pots are 500k whereas those in my Fender are 250k. My parallel wiring will give a higher peak frequency than the standard but the Fender pots will reduce the peak height. So I decided to install 500k pots to raise the height (not frequency) of the resonant peak, and decided that if I was going to bother I may as well use push-pull (DPDT) volume pots so I could switch each pickup independently between series and parallel.

Rather than the fantastically expensive DiMarzio push-pull pots, I used cheaper alpha pots from StewMac in the US (since I was ordering some other bits and bobs anyway). DiMarzio helpfully have lots of wiring diagrams for various configurations, I used this one but altered it so series engaged with the pot out rather than in: [url="http://www.dimarzio.com/sites/default/files/diagrams/pj_2ppdualsndv1t.pdf"]http://www.dimarzio....pdualsndv1t.pdf[/url]


Anyway...the most important thing from my perspective is that increasing the pot values to 500k gave me exactly the effect I was after. The treble 'bite' is much more prominent while the low end authority of the bass is preserved. Tbh I was surprised how much of a subjective difference it made, that peculiar effect where the bass just feels easier to play. With both pickups on full I get a classic 70s and 80s-style jazz bass tone - more Larry than Marcus, with tons of character and aggressive enough to cut through a mix when I dig in hard. It doesn't quite have the airy extended top end of the real US Fender Vintage 75 pickups (which I have on another bass) but is very good and sounds like a Fender jazz nonetheless. Soloing each pickup gives very useable versions of the classic JB single-pickup tones. Switching each pickup into series mode, the most obvious effects with both pickups on full is an increase in volume. Compensating for this you can hear the shift in resonant peak, giving a more 'middy' sound with a bit more oomph in the bass. Where it really comes into its own is with each pickup solo'd or combining series/parallel. The neck pickup in series is instant 'Precision', while the bridge has a handy low-end boost making that 'Jaco-esque' sound useable in a wider range of situations at the expense of a little treble. The tone control also has a very obviously different character when the pickups are in series versus parallel.

Overall, I think if you bother to install DiMarzios at all it's worth spending the extra at least on 500k pots, ideally on the push-pull variants. You could even use a third on the tone knob either to mimic the Fender s1 mod or give phase-reverse options, though I am happy enough as is. I may at some point try a 1Meg pot on the tone for a further small increase in brightness, but right now this is at last giving me the sounds that I've been after for a very long time. It's extremely versatile, if I had to choose one setting it would be all parallel, everything on full. But I don't have to choose, woo! Playing with combinations of series-parallel/varying volume whilst playing along with various funk, pop etc tracks, I've found it fairly easy to get a tone that's a reasonable match to whatever I'm listening to, even (to an extent) with records that use a Stingray. I am now very happy indeed with these pickups.

[redstriper]

Excellent review - thanks.
It's interesting how every Jazz bass sounds different depending on the pick ups and electrics, yet they all still sound like a Jazz bass somehow.

[LawrenceH]

[quote name='redstriper' timestamp='1326672208' post='1500421']
It's interesting how every Jazz bass sounds different depending on the pick ups and electrics, yet they all still sound like a Jazz bass somehow.
[/quote]

Yup indeed they do, I'd attribute a lot of that to the characteristic comb-filtering created by the pickup spacing/position.

[DoesThisBassLookBigOnMe]

Just wanted to say thanks for this review. In my opinion, although the end result of anyone's tweaking of an instrument is always subjective, I really appreciate how you've shared the technical aspects of the installation so clearly. It's far more useful than the regurgitated marketing weasel speak usually associated with things like pickup reviews (and a very large portion of other musical products!).

[betterbisque]

Good post, thanks.
Wish I'd found it sooner. I have an old JB and in the mid/later 80's I installed a set of these. They were supposedly the best thing out then, but I didn't really know one end of one from the other, just followed the instructions and wired them in. I remember they were far superior to the old Fenders that were in there, and where those got to who knowns. Then the JB was put away for about 18 years. Recently had it out and decided I was not as impressed with them as I used to be. A bid dead and flat compared to the Joe Bardens, TV Jones and Lollars I have in my new basses. But never knew about these wiring options and 500 ohm pot ideas. So anyway, this week I installed a new set of Lollars and they are far superior. Smooth, warm, but turn the tone and blend the pups and pop, there is that JB clear as a bell.
I didn't know what the DiMazio's were until I took them out and looked then up. It's been maybe 25 years since I bought them. I was going to toss them in the parts bin, but now I am having a rethink as a result of this post.
Thanks
Steve
ExPat Kiwi in CA

[Chienmortbb]

I had one of these in my Aerodyne PJ but with the original 250K Aerodyne pot values. Change the pots to 500K as recommended by DiMarzio and it was a relevation.