Pickup Experts - adding a baseplate to a Jazzmaster Pickup

jellybelly

Hi guys, and specifically Pickups experts! Was thinking about getting the bridge pickup on my JM re-done AGAIN. Its a slightly overwound A3 type from Mojo - sounds great, don't get me wrong, but I wish it had a bit more of an emphasis on the lows and low mids rather than the bright bark it's currently got - it's brighter than either my Jaguar (Oil City A5s) or Esquire (Mojo A3). Pots all the same or roughly so, so it's not down to this. (I kind of feel JM Pickups sense too much of the string right by the bridge - would a narrower strat/tele/jag pickup be less bright if centred on the same polepieces?) 

Anyway, I was considering adding a brass baseplate to achieve a little bit of what the Jag and Tele have going on but maintaining the basic tone of the pickup - I'd use a flat P90 plate as they're pretty much the right size and are cheap and easily available. As a test I believe I just stick it to the bottom with something between the magnets and plate like electrical tape and ground it. If I like it I'll pot it. 

Will this work? For the sake of a couple of £ I'm willing to take a punt but as always I'm interested to hear opinions and alternate options. Cheers! 

MartinB

I'm no expert, but I think a big part of what a tele baseplate does is related to its magnetic properties, being made of steel.  I have messed around with sticking a strip of mild steel to the bottom of a strat bridge pickup, and it did seem to thicken things up a bit.  I'm not sure a brass baseplate would have the same effect. 

impmann

MartinB said:

I'm no expert, but I think a big part of what a tele baseplate does is related to its magnetic properties, being made of steel.  I have messed around with sticking a strip of mild steel to the bottom of a strat bridge pickup, and it did seem to thicken things up a bit.  I'm not sure a brass baseplate would have the same effect. 

Its brass or copper under some Tele pickups...

I'd imagine that it would have *an effect* but whether it will have the desired one will be a matter of experimentation. I'd also venture that the baseplate on a Tele pickup is a bit thicker than the bassplate of a P90... I think.

ThorpyFX

I have a mojo humbucker (in a JM cover) in the bridge position. For me it has removed the icepick nature of that pickup and has given me a really versatile guitar.

earwighoney

jellybelly said:

Hi guys, and specifically Pickups experts! Was thinking about getting the bridge pickup on my JM re-done AGAIN. Its a slightly overwound A3 type from Mojo - sounds great, don't get me wrong, but I wish it had a bit more of an emphasis on the lows and low mids rather than the bright bark it's currently got - it's brighter than either my Jaguar (Oil City A5s) or Esquire (Mojo A3). Pots all the same or roughly so, so it's not down to this. (I kind of feel JM Pickups sense too much of the string right by the bridge - would a narrower strat/tele/jag pickup be less bright if centred on the same polepieces?) 

Anyway, I was considering adding a brass baseplate to achieve a little bit of what the Jag and Tele have going on but maintaining the basic tone of the pickup - I'd use a flat P90 plate as they're pretty much the right size and are cheap and easily available. As a test I believe I just stick it to the bottom with something between the magnets and plate like electrical tape and ground it. If I like it I'll pot it. 

Will this work? For the sake of a couple of £ I'm willing to take a punt but as always I'm interested to hear opinions and alternate options. Cheer! 

No idea, but I know that Jese Loureiro makes a JM pickup with a baseplate

http://jlguitars.eu/shop/index.php?id_product=38&controller=product&id_lang=4

Alegree

MartinB said:

I'm no expert, but I think a big part of what a tele baseplate does is related to its magnetic properties, being made of steel.  I have messed around with sticking a strip of mild steel to the bottom of a strat bridge pickup, and it did seem to thicken things up a bit.  I'm not sure a brass baseplate would have the same effect. 

Bang on. Although copper will have a damping affect on the treble (like adding a brass cover to a humbucker, albeit lesser so). Magnetic baseplates seem to affect the lower frequencies as well as the high ones.

Roland

If you trust yourself with a hacksaw then you could cut some simple plates yourself and experiment. They don't have to be full plates with screw holes. You can cut then to fit inside the screws, and fix underneath the pickup with double sided tape (being careful not to short any contacts). That will give you an idea of the effect without the cost of new pickups.

Alegree

Roland said:

If you trust yourself with a hacksaw then you could cut some simple plates yourself and experiment. They don't have to be full plates with screw holes. You can cut then to fit inside the screws, and fix underneath the pickup with double sided tape (being careful not to short any contacts). That will give you an idea of the effect without the cost of new pickups.

Must be very thin double sided tape though. Any gaps severely reduces the affect.

Roland

As it happens I've got an offcut on my workbench which will do. It's 3cm x 8cm, and 2mm thick. If you're interested then PM me an address and I'll post it.

OilCityPickups

Ferrous baseplates increase the inductance of a pickup and thus shift it's resonant peak slightly downward, fattening the sound up.

impmann said:

MartinB said:

I'm no expert, but I think a big part of what a tele baseplate does is related to its magnetic properties, being made of steel.  I have messed around with sticking a strip of mild steel to the bottom of a strat bridge pickup, and it did seem to thicken things up a bit.  I'm not sure a brass baseplate would have the same effect. 

Its brass or copper under some Tele pickups...

I'd imagine that it would have *an effect* but whether it will have the desired one will be a matter of experimentation. I'd also venture that the baseplate on a Tele pickup is a bit thicker than the bassplate of a P90... I think.

Tele pickups have copper plated steel baseplates (early ones were steel with no plating at all ... these rusted hence the plating) ... some cheap copies have brass ones which generally sound pants. 

jellybelly

@Roland I'll take you up on that mate, worth a shot! Thanks all for info, great to have such knowledgeable people offering advice freely . 

jellybelly

Alright guys, had a bit of an experiment this evening. 

Mr @Roland ;;; true to his word, sent me a roughly p90-sized piece of metal with some sticky-back tape.

Before taking it apart, I gave my JM a good 15 mins on the bridge pickup through my THR's 'lead' mode (plexi-style) set for a little breakup. Pickup as-is has present highs, upper mid spike and a relatively thin low end (compared to my Tele and Jag anyway). For reference, i generally run the volume (300k) between 8 and 10, and the tone (500k, 0.047mf) between 4 and 7 on the bridge pickup. 

Unstrung, and pickup cover removed, I installed the metal plate. The magnets protrude very slightly from the bottom so I may need to do something about that if/when it comes to making it permenant. Doesn't matter for low volume testing - the covers and foam underneath kept everything in place but potting it I imagine would be a minimum requirement. 

So, strung it back up and adjusted the pickup to the same height as before and plugged it in...

Firstly, its louder, more aggressive, and the whole frequency response has shifted toward the bass and low mids, with the highs being chunkier with, surprise surprise, some of that telecaster attack. It also seems a bit more compressed, though it might just be an effect of increased output. I'm having to roll down the volume to about 8 to get it sounding 'clean', so it's less responsive from this perspective than before. The lows are the biggest change, it's got that thunk to the lows that a Jazzmaster always hints at. My reference 'aggressive Jazzmaster bridge tone', the intro to Kool Thing, is definitely there now with no massive eq adjustments. 

All in all, I'm happy with the change (I'm hesitant to call it an 'improvement'), I just need to figure out what needs to happen to make it 'permanent'. 

I will also endeavour to pay a good deed forward to another member of the Fretboad community whenever I'm able to . 

Alegree

That's great, confirming that we're not just talking hot air

I'd imagine if you were running on the normal double 1 meg pots you'd notice a more significant difference.

jellybelly

So, will I experience noise with the pickup as-is, or will I need to drill to accommodate pole pieces and pot it to ensure no microphonics? It's pretty snug at the moment with plenty of foam keeping it in place but no idea how it'll react in a live/loud situation!

Alegree

I wouldn't worry about it if you've got it pressed up against foam. 
If you're really bothered you could melt a candle and press it on with some molten wax to hold it, but I doubt it'll be necessary.