Metal Scratchplates & Effects On Pickups

Nomad

What effects do metal scratchplates have on pickups? I'd imagine aluminium would be pretty inert, but what about brass and steel?

OilCityPickups

Non ferrous metals won't have much effect ... apart from shielding the wiring underneath to a degree.  As for steel ...you can see a Telecaster bridge as a sort of mini scratchplate ... and that has a small but definite effect on the pickups inductance and therefore it's resonant peak. Steel (ferrous material) in, or close to the magnetic field smooths out treble and boosts bass slightly. 

ICBM

I think anodized aluminium guards do have a small effect on the tone, despite being non-ferrous. Even if non-ferrous, metal in the magnetic field does modify it, due to eddy currents - and although the guard is not in the direct field between the magnets and the strings, it's still in the part that 'wraps around' the sides of the pickup.

Brass ones (unless chrome plated) have the effect of making the guitar look like a modded horror from the 1970s, so should be avoided at all costs anyway.

steamabacus

I worked on a friend's guitar (Squier Strat) both before and after it having a solid copper scratchplate fitted and there was a definite change in tone.

It was a particularly nice guitar (I just remember it having 'something' special about it) with some nice Amalfitano pickups, so it was noticeable that the tone had changed slightly when (some months later) I re-fitted the pickups in the copper scratchplate (which was made by another friend). In fact, I thought it might have lost just a little about whatever was special about it in the first place - I think I preferred it before. It seemed to be slightly more rounded, slightly fuller but, at the same time, slightly less 'lively'. A little more 'reserved', maybe?

I've often wondered quite what was responsible for the change (which, I stress, was slight but seemed real). The guitar was definitely 'quieter' (in terms of buzz and interference) but was the extra screening dulling the highs a little? The new copper 'plate meant the guitar was also a bit heavier - could the extra mass be the cause? Another thought I had was that the copper 'plate was more rigid than the plastic one - was the suspension of the pickups from this (a 'stiffer', less microphonic mounting) a factor? Or a combination of causes?

Whatever the causes, the guitar sounded different with the copper scratchplate.

ICBM

steamabacus said:

I've often wondered quite what was responsible for the change (which, I stress, was slight but seemed real). The guitar was definitely 'quieter' (in terms of buzz and interference) but was the extra screening dulling the highs a little? The new copper 'plate meant the guitar was also a bit heavier - could the extra mass be the cause? Another thought I had was that the copper 'plate was more rigid than the plastic one - was the suspension of the pickups from this (a 'stiffer', less microphonic mounting) a factor? Or a combination of causes?

Eddy currents.

OilCityPickups

All metals around the pickup will have some effect ... it may be small as with aluminium ... or large as with steel ... but as ICBM says: the non ferrous stuff messes with the eddy currents, the ferrous stuff messes with the inductance/eddy currents a fair bit more. And I agree about pickup suspension ... there is a definite difference in the sound of a body mounted pickup to that of a scratchplate mounted one ... one of the reasons I find it difficult to tell customers how my pickups will sound in their instrument ... it depends how you use em!!!

Nomad

Thanks folks. Most interesting.

Minging though it may be, I was thinking of some brass sheet (allowed to naturally tarnish, I should point out). This would be for a lap steel, incidentally.

steamabacus

Nomad said:

Thanks folks. Most interesting.

Minging though it may be, I was thinking of some brass sheet (allowed to naturally tarnish, I should point out). This would be for a lap steel, incidentally.

Done right, that could look great. I'm a big fan of what James Trussart creates.

Nomad

steamabacus said:

Done right, that could look great. I'm a big fan of what James Trussart creates.

Don't think I'll be going that far.

The plan is a meranti body (got the wood in yesterday) and I'm thinking a dull matt brass plate. When I get a chance, I'll mess around with oiling an offcut of the wood and see how it looks with the brass (of which I have plenty of bits and bobs). The other option is some tort plastic, which I have a sheet of.

imalone

ICBM said:

steamabacus said:

I've often wondered quite what was responsible for the change (which, I stress, was slight but seemed real). The guitar was definitely 'quieter' (in terms of buzz and interference) but was the extra screening dulling the highs a little? The new copper 'plate meant the guitar was also a bit heavier - could the extra mass be the cause? Another thought I had was that the copper 'plate was more rigid than the plastic one - was the suspension of the pickups from this (a 'stiffer', less microphonic mounting) a factor? Or a combination of causes?

Eddy currents.

Eddies in the time space continuum.

steamabacus

imalone said:

ICBM said:

steamabacus said:

I've often wondered quite what was responsible for the change (which, I stress, was slight but seemed real). The guitar was definitely 'quieter' (in terms of buzz and interference) but was the extra screening dulling the highs a little? The new copper 'plate meant the guitar was also a bit heavier - could the extra mass be the cause? Another thought I had was that the copper 'plate was more rigid than the plastic one - was the suspension of the pickups from this (a 'stiffer', less microphonic mounting) a factor? Or a combination of causes?

Eddy currents.

Eddies in the time space continuum.

Is he, indeed? 


https://www.youtube.com/watch?v=LvQuJ1xnjhc

Nomad

steamabacus said:

imalone said:

ICBM said:

Eddy currents.

Eddies in the time space continuum.

Is he, indeed? 

Presumably because he's our overly-cheery shipboard computer.

The tort scratchplate doesn't really go with the wood with just a lick of oil on it, but the brass does. I might try a bit of stain and see how that goes, but leaning towards the brass so far.

Nomad

Duplicate post.

imalone

Edit, wink was at steamabacus for getting the HG2tG ref, though I suppose nomad should get one too. Oddly ended up accidentally winking at people twice yesterday. Explaining it probably makes it worse...