Pickup Magnets - How Big A Difference?

ESchap

ICBM said:

I think it's due to them being made like that in the 50s, therefore they must sound better.

Actually, surface roughness of a magnet does affect it's magnetic anisotropy, coercivity, magnetoresistance,

and magnetic domain structure  ... not sure any of those were invented in the '50's though ....

Following quote from Tim Mills on his forum in 2005 makes more simplistic sense ....

• Unpolished magnets where used in all the early P90s and PAFs-predominantly Alnico II, III,and IV-the move to using alnico V didn't come till about '61.
  An unpolished magnet has a rough finish to it and is also longer at 63.5mm as opposed to the newer polished magnets at 60mm.
  The magnets are made individually and cast in sand, the magnetic axis are then ground for a flush fit up to the pole shoe on one side and slugs on the other.
  
  There are various claims of benefits of unpolished over polished/ground magnets but for me the slightly longer length imparts a more balanced response from the pickup. It's particularly noticeable in the unpolished Alnico Vs we use, probably because they're the most powerful, the tone isn't as hard/blunt as a polished magnet and string sustain is better too.
  
  Also they're nicer to work with

imalone

ESchap said:

ICBM said:

I think it's due to them being made like that in the 50s, therefore they must sound better.

Actually, surface roughness of a magnet does affect it's magnetic anisotropy, coercivity, magnetoresistance,

and magnetic domain structure  ... not sure any of those were invented in the '50's though ....

Following quote from Tim Mills on his forum in 2005 makes more simplistic sense ....

• Unpolished magnets where used in all the early P90s and PAFs-predominantly Alnico II, III,and IV-the move to using alnico V didn't come till about '61.
  An unpolished magnet has a rough finish to it and is also longer at 63.5mm as opposed to the newer polished magnets at 60mm.
  The magnets are made individually and cast in sand, the magnetic axis are then ground for a flush fit up to the pole shoe on one side and slugs on the other.
  
  There are various claims of benefits of unpolished over polished/ground magnets but for me the slightly longer length imparts a more balanced response from the pickup. It's particularly noticeable in the unpolished Alnico Vs we use, probably because they're the most powerful, the tone isn't as hard/blunt as a polished magnet and string sustain is better too.
  
  Also they're nicer to work with

Domain structure might be influenced during formation by the surface, but it's a bulk property, so polishing afterwards wouldn't make much difference, it's a big determinant of the other things. That's why I'm wondering about the sintered vs sand-cast thing. Materials scientists did know about this stuff in the 50s (and earlier), but manufacturing types might not and pickup builders probably didn't worry much.
This is the first old paper (a thesis from '66) I managed to turn up on it, but refers back to earlier work in the 30s too, which would have all been by people who understood crystal structures and things. http://alexandria.tue.nl/extra3/proefschrift/PRF1A/6701749.pdf

I guess 5% more magnet might make a difference too

Van_Hayden

The rough cast ones tend to display magnetic irregularities along the face, the machined ones are much more consistent.

I've got it all in my little black book but like most things trust ears. You can hear a difference but it's small (like most things with much mojo attached)

Although most magnet suppliers use rough cast as an excuse to make a poor magnet these days. Cermag won't do them as they can't guarantee the magnetic performance, most of the far eastern stuff is pants.

OilCityPickups

Van_Hayden said:

The rough cast ones tend to display magnetic irregularities along the face, the machined ones are much more consistent.

I've got it all in my little black book but like most things trust ears. You can hear a difference but it's small (like most things with much mojo attached)

Although most magnet suppliers use rough cast as an excuse to make a poor magnet these days. Cermag won't do them as they can't guarantee the magnetic performance, most of the far eastern stuff is pants.

Quite right ... I get mine from the US and they are consistent .... but ow what a premium!!!

An alnico 4 polished (destined for an oil City Nightfighter) nestles next to an alnico 4 rough cast

ICBM

ESchap said:

ICBM said:

I think it's due to them being made like that in the 50s, therefore they must sound better.

Actually, surface roughness of a magnet does affect it's magnetic anisotropy, coercivity, magnetoresistance,

and magnetic domain structure

Ha! I don't doubt that there could be physical properties which are genuinely different - although probably subtle - I just meant that whatever way something was done in the 1950s is assumed to be better than whatever way it was done later. If they'd been smooth-ground in the 50s and rough-cast in the 70s, guitarists would attach 'mojo' to smooth magnets, and call the rough ones 'cheap' or something...

Nomad

Put the A2s in late last night. Anyone working on the Wilkinson WVC pickups may like to know that they're wax potted. The swap was easy enough once I managed to get the covers off (desoldering braid and a gas-powered soldering iron with a big chisel tip did the job). I had already marked the magnets with the type and orientation of north, so everything went in properly. I also marked the Wilkinson magnets as they came out.

I decided to leave the covers off for now, on the basis that I'll probably be trying the A4s and A8s at some point. They're nickel silver, but I'm not sure how much effect they would have on the tone.

Been twanging on and off for most of the day. The guitar is the aforementioned Vintage Lemon Drop (with 22nF tone caps), amp is a Laney Cub 10, and I used a TC Nova Drive into a TC HoF reverb. Amp gain set low, volume from half way to 3/4. Not been playing rhythm or riffs - just lead.

My initial impression was that everything is much brighter and the neck pickup sounds a bit thinner. Turning the amp's tone down to about half way helped to tame the brightness, but I felt the neck pickup still wasn't producing the sort of thick distorted lead sound I like. The bridge pickup seemed a bit better, however. I think I'll need to work on the distortion sounds for a bit - the Nova Drive has programmable presets, and mine were made with the original magnets. I'll copy my patches into new banks and tweak things to suit.

When I switched off the distortion pedal, the difference was much more evident. Definitely a sweeter sound from the bridge pickup - it now has a lovely 'ooo' sound (something I call toffee tone). Before, it just didn't have this to anything like the same extent. With the A5 magnets, the toffee tone was much more evident on the neck pickup than the bridge, but I felt it lacked a bit of top end. Switching this to A2 has certainly added top and the toffee tone comes across better. As with the distortion, it also sounds a bit thinner than before when played clean, but this might explain the better definition I hear in the low notes (first few frets on the E and A strings). With A5, these tended to be a bit woolly, but now I can twang quite hard on them and the notes are much clearer. Before, the toffee tone tended to be most evident around the 10th-15th frets and less noticeable lower down, but it's now evident all over the neck (if lacking that little bit of body around the octave).

Overall, it's like playing a different guitar, especially with the clean sound. Response to picking dynamics was already pretty good, and seems to have improved with the A2, not necessarily in terms of dynamic range, but the toffee tone seems to work really well when digging in, especially with string bends. Words like "warm", "sweet" and "tuneful" come to mind.

The plan is to keep the A2s in for a week or so to get used to the sound and then try another grade. As things stand, I like the tone from the A2s, especially in the bridge pickup (transformed, really), but I'm curious to see what happens with the neck pickup (I either adapt to the new characteristic tone, or discover something I prefer with a different grade of magnet).I find myself wondering if the Cermag A5s will sound noticeably different from the original A5s.

Nomad

Did a recording...

Guitar straight into clean amp, no effects. Amp tone on 2/3rds. Recorded with a Rode M3 midway between cone edge and centre, EQ flat during recording and mixing (no EQ at all). Some compression on the guitar in post (vintage DBX165 according to the button I clicked in the software), and a touch of fairly spacious reverb. Mild overall reverb applied to the mix.

richardhomer

The added brightness is likely - at least in part - to be down to having removed the covers. My experience of Alnico II pick-ups is that their 'very' high-end is soft and somewhat attenuated, compared to say Alnico V.

This gives them a very 'musical' tone which takes drive well.

I appreciate you may be happier with the sound you now have but to meaningfully compare the effect of the new magnets with the original, you need the covers on.

ICBM

richardhomer said:

I appreciate you may be happier with the sound you now have but to meaningfully compare the effect of the new magnets with the original, you need the covers on.

+1. Covers can have a significant effect on the tone, which varies depending both on the cover material and the pickup type - Alnico II is more affected by covers than Alnico V, and both more than ceramic, in my experience. Higher-wound pickups seem to be more affected than lower-wound ones.

I'm actually not a fan of Alnico II for lower-wound pickups, I find it sounds thin. I do very much like the Duncan Custom Custom though - Alnico II, but a very high wind by traditional standards (14.4K). It's one of the pickups most affected by a cover, too.

Nomad

Agreed that the covers should be on if I want the guitar to end up with the covers on (which I would prefer). However, how much effect can be expected from nickel-silver? (If it helps, the metal is 0.5mm thick, and one cover weighs 24g.)

I feel I should mention that my comments about thinness and brightness were my first impression and were the result of playing at reasonable volume about half an hour after waking up, so there is a possibility that my ears weren't responding as favourably to the sound as they might have been doing later. There certainly is a difference, and I think my thoughts on needing to rework the distortion sounds are probably valid. Playing with distortion set up for a different base sound isn't really the best way to assess the pickups themselves.

I have to say that when I switched to the clean sound, it was something of a revelation. My impression here was that the sound is clearer, brighter but still smooth. Even if there is a small change in top end with the covers, I should be able to compensate (if desired) with the amp's tone control. The compensation might not result in getting exactly the same sound as I do at present, but I don't think that's terribly important right now. For me, the tone hunt is more about striking a balance between getting something I like and working with what I've got, so a small change in tonal balance due to the covers is neither here nor there if the end result is still close to the bigger change that has come about from swapping the magnets.

There is certainly no paradigm guitar tone (in my head or on a recording) that I'm trying to get to - it's much more about finding a sound that I gel with. Although I talk about something I call toffee tone (something mellow but clear, with an 'ooo' character), if there is such a sound in my head, it's somewhat vague and is likely a distillation of many guitar sounds that I've heard over the years. Getting comfortably into whatever that ballpark is will be good enough - there are other factors that affect what one hears at any given moment (volume, room, position, MkI lug-ole, mood of the player, etc) to spend time chasing after something that's supposedly 'perfect'.

Right now, I'm really pleased with the change in tone. Last night, I kept listening to the recording and trying to affirm that this is what my guitar now sounds like. I sometimes wondered (and still am) if I had been missing something all along with the A5s and that I'm kidding myself about the difference.

Comparison is all very well but it can become a somewhat academic or analytical affair with a risk of spending forever tweaking and adjusting things. What really matters, for me, is my emotional response to the sounds I hear when I play, and my ears are telling me that it sounds good. I'm very tempted to just put the covers back on and call it done.

richardhomer

Whether you are delighted with the sound now or not, all ICBM and me were pointing out was that some of the difference you are hearing will be down to the covers - some will be down to the magnets.

If you are trying to establish how much difference the magnets themselves make, you will need to put the covers back. The only reason I bothered to post this in the first place was because added brightness is not a characteristic I associate with Alnico II.

Incidentally, when Paul Reed Smith started making the McCarty model, the pick-ups were Dragons with covers on. His view was that they significantly dampened high-end - which was what he was after.

Nomad

As I said in my previous post, the differences between magnets might be interesting, but they aren't the most important thing for me - the end result is what matters. The A2s sound better to me than the original magnets, so the original ones are essentially forgotten. They will never go back into the guitar. What counts is what it sounds like now. I may well change from the A2s to something else in the future, but until then, I'll see how things go with the A2s.

The covers are back on, and I would say that, if there is a difference, it isn't exactly huge. Recording...

https://soundcloud.com/nomad-z/jazzy-jam-2

Exactly the same settings throughout, including mic position. (Both guitar clips were normalised to -3dB after cropping to the selected section.)