Closed faced Mini humbuckers are associated with one guitar usually - the Gibson® Firebird! They actually turn up on a few other makes and models, but its the Firebird® we all think of when we see this style of cover/pickup.
The pickups in that guitar, originally, were actually a bit of a departure from what had been before - rather then using a bar magnet and steel poles (either poke screws and slug, ala a "normal HB", Pole Screws and steel bars, ala a "traditional mini HB" or even the modern Firebird offerings, which simply use 2 steel bars!) the real deal Firebird® Mini humbucker used 2 bar magnets, slotted into the housings on the bobbins.
Theres plenty of debate as to what magnets they actually used originally, but whatever they were, its certainly an important part of the construction if you're going for historically correct re-winds and re-designs.
Either way, these are the covers for those types of jobs! No holes for poles, just a completely solid face, nicely finished over a base of German Silver.
So lets get straight into it.
This is where we can actually get back to speaking about our covers!
For all of our covers, we use Nickel (what I’m going to call “German silver” from here on out) – it’s a fantastic metal to electroplate, so you can have a fantastic range of colours, and it’s the most “tonally neutral”, so has the least impact on the sound of your pickup, because, lets be honest – if you’re going to the trouble of putting a cover on the thing, I bet you quite like how it sounds now right?!
The alternative “base” material, would be brass – not without its charms, but far from tonally pure – it has this weird habit of muddying the pickup – no one seems to know why (if anyone cares to enlighten me, I’m all ears!), but brass parts on humbuckers seem to attenuate the top end – so for the time being atleast, we avoid it (maybe in the future, it’ll be something we expand into)
On top of the base, at least with the plated covers, you’ll find a very fine layer of highly conductive copper that’s used to give the best possible finish to the Electroplating, and then on top of that, you’ve got the final colour, the electroplated finish
For the tonal purists out there, it’s worth noting that copper “under plate” – it doesn’t make a massive difference to the sound of the things, and it really does help give the best possible finish – but I know there are those who don’t like it, so, full disclosure – its there! (obviously, excluding the unplated version – that’s just pure nickel)
So we know what the things made of, and we’ve got a good idea of what size we need! How do we fit them?! Well – the unavoidable answer is by soldering them to the base of the humbuckers. I wish it wasn’t the case, but it really is the best way to do it!
An ungrounded cover (that’s basically what you’re soldering them for) is prone to act as an antenna that will pick up every scrap of interference in and around the guitar – so as well as acting as a solid point to affix the thing; it also saves you from ending up with a noisy pickup.
Its not too bad a job really – you need to raise the screw poles a little on the pickup, remove the cloth backed tape around the edge of the bobbins , and port the cover into its final position over the pickup. Mark the centre points on either side (between the D and G poles is usually a good spot – but no need to be accurate), remove the cover, and sand down to expose the nickel underneath the plating and copper.
Once you’re through, you can put the cover back in place, and solder in in place, and you’re job done – securely mounted, and grounded.
Now, there’s also the contentious matter of wax potting – I’m going to stick my neck on the line and say “yes, you will definitely need to re-pot a pickup once you’ve fitted a cover” – but I know full well, its not strictly true. Chances are your coils are already potted pretty well, and you’ll be fine if you don’t… but we all know that we don’t live in a perfect world – so if you do notice your pickup is feeding back more often with covers fitted, then it might be time to research wax potting. (I’ll skip the intricate details for now)
Right – this is the fun part! The purely cosmetic part where its completely up to you what you go for! (No tech support required!) We’re really just including this to make sure theres no confusion when it comes to the more subtle differences.
It is what it is – fairly low karat gold is usually the case when it comes to plating (atleast outside of jewellery) – interestingly, the variation between different parts in gold comes down to the karat of gold used in the plating – the darker, more orange gold colours come from higher quality gold. Ours are fairly middle of the road “guitar part gold” to be honest. Worth nothing that whilst gold normally wont tarnish, it will get dirty, and cleaning gold plate is the very devil, because its soft and thin (we’ve all seem gold humbuckers where the platings rubbed off – that’s why! Its not that its cheap gold, or “not gold” (granted, its low karat usually)) – it’s possible to just rub straight through most gold plate with a bit of force and abrasion. So go for gold (all gold, not just our humbuckers covers – but anything gold plated!) with caution – looks great, but If its getting used and abused everyday, its going to show its age.
Black is Black – it’s commonly thought to be power coating or painted, but it is actually Electroplating (in a fashion anyway), and as such, offers all the benefits/drawbacks there within – it’s actually a process that causes oxidisation of the base material (that copper layer) which is then converted into Cupric Oxide. Its not exactly common with humbuckers covers, but it looks fantastic as long as you keep it clean!
These are just the unfinished covers, no copper under plate, no electroplate, as pure as they come – just a shaped hunk of German silver, completely with little tool marks and scuffs from manufacture. A nice little part to use as a “ready made” relic, but they can be polished up with a metal polish to a mirror shine. Without an electroplating, they age very quickly – so aftera year or two of serious playing, expect to see that zebra stripe pattern where you’ve hit the cover with your pick, but never under the strings.
You’ll see Cosmo being called “Black Nickel” or “Ruthenium” – but its all the same thing, a sort of gun metal grey, somewhere between Chrome and Black. Really nice colour, and often turns up on Ibanez® guitars, but its very rare as a humbuckers cover colour. It’s a fairly stable element though, decent scratch and wear resistance, and not overly reactive, so it won’t tarnish too easily. Again, just like black – got to keep it clean – it shows up finger prints.
Chrome & Nickel
Now Chrome and Nickel are a strange one – you ask 90% of guitarists what colour hardware they’ve got on their guitar, and they’ll answer ”chrome” – but it’s actually much rarer then you think (or at least it was, its becoming more common because it’s a great material for plating!) – High wear resistance, good scratch resistance, and very little reaction to acids (that’d be out sweat!) – it’s a great choice if you like silver.
Weirdly though, it wasn’t really used until recently – most “silver” hardware you’ll see on guitars before the 1990s, will have been nickel plated. Not a clue as to why. It’s not too tricky a job to ID though if you’re in any doubt. Chrome has a certain blue tint to it – think about a screw driver, a pair of pliers, that’s chrome plate. Nickel has a slightly more yellowy tint to it, if you’re looking for examples – normally turns up on more decorative stuff, but if you’re struggling, the low strings on your guitar will be nickel wound.