when are magnets too strong?

[black_labb]

hi guys, i have picked up some magnets for some pickups for a bass. the pickups will be passive singl coils. the neck pickup will be 2 6mmx20mm long alnico 6 magnets per string (for a 5 string) and the bridge, which is the one i am a bit worried about uses 1 10mmx30mm long magnet. i was hoping to get them 20-25mm long, but the place i got them from only had 30mm long, and the 8x24mm were out of stock. would you guys think this would be too much string pull? it is a bass, and the bridge pickup, but they are very strong for alnico mags due to their size.

do you think this size mags would start to create "wolf tones" even in the bridge position?


thanks

[David Schwab]

do you think this size mags would start to create "wolf tones" even in the bridge position?

I've never seen that problem with alnico bar magnets on a bass. I use two neodymium magnets in my passive pickups, and I have them very close to the strings. They are listed at 4480 Gauss.

I did have a P-bass pickup that did the "stratitus" thing when I get it really close to the strings.. but it was really close.

[black_labb]

thanks for that, i should be fine then.

for some reason the place i've been getting my mags from has massively increased the price of alnico's. when i went in last time the guy discounted some things, but they are rediculous and not logical.

prices are in australian dollars (about 90 or so us cents atm)
the 5mmx20mm alnico rods have gone up from $2.10 to $7.60
the 10mmx30mm have stayed at 6.30,
thats exactly 6 times the magnetic volume for less money!!

the only other size that seems reasonably priced is the 8mmx24mm at 5.04 (or cheaper over 10)

all the small ones that seem reasonable for making guitar pickups are way overpriced, the sizes only suitable for bass seem ok. might have to start using a different supplier for my guitar pickups, but its kind of nice as the place is just near the luthier i get my fretwire from and i can walk in and ask for what i want.

http://www.amfmagnetics.com.au/produ...ctionName=Rods

[chevalij]

Check out the world prices on Cobalt. It's gone through the roof in the past few months.

[chevalij]

I just checked that website. Are those prices for EACH? That is absolutely freaking wrong. Even at his 100+ price I can get about 25 times the qty for the same cost!

[black_labb]

yep they are, when i went in last i didnt realise the price went up, but i got a discount (because i was taking the alnico's he said). he said the reason for the uneven prices is that when they get a big order of a certain variety they will order extras to sell to people with smaller orders.

just out of curiousity, how would 1.20 per rod (the 100+ price before the hike) have compared to your sources? things like magnets and materials like this tend to be priced a fair bit higher in australia due to the small and relatively isolated market. on the other hand, basic wages are higher which is good in a way.

in reality, they probably dont sell that much alnico and want to see if they can get some profit by upping the profit margin a huge amount, or just stop stocking them.

[mick]

AMF are fucking useless , I asked them for a quote on 5000 mags and they couldn't be bothered answering , mind you at those prices they probably thought I wouldn't be able to pay for them..nor would I want to..

Mick

[black_labb]

they never really seemed to be that great, but so convenient for me.

having said that ill probably be buying some more parts from you, especially if i cant get the odd magnets i like to experement with without spending the cost of a mass produced pickup just on the magnets. i havent wound those 4 humbuckers that i ordered parts for from you yet, as im back at uni and have less time and more instrumens to build before the pups can go in.

by the way, the bobbins for the filister head screws seem to be too tight for the screws, do they need to be tapped? i could screw the screw into the material, but it was a bit strained and the screw head wasnt perfect after that. sorry to ask such a silly question, but ive never would any pickups that i didnt make the bobbin for.

[David King]

BL,
You say you are using 2 of the 6 x 20 mm magnets for each string?? that seems like a lot more magnet than is necessary. I think you will get serious problems with wolf tones, (Dave S. seems to think you are using 2 rectangular magnets down under the coils with polepieces to transmit towards the string but that's not what I read.)
30 x 10 mm long single magnets is also pretty extreme. I'd be tempted to cut those in half or just degauss them all. You only really need the double magnets with the B and E strings that have the long excusions. a single 6 mm ought to work for the high strings but I doubt you could get all the strings to balance without a lot of futzing around.

Your magnet dealer is robbing you blind. I'd try ordering straight from HK or China. Those 5 x 20mm mags should cost about about $.50 ea at current global prices from a China source.

[David Schwab]

(Dave S. seems to think you are using 2 rectangular magnets down under the coils with polepieces to transmit towards the string but that's not what I read.)

Yeah, I was. There was too many "mm's" in his description and I got lost lol

Obviously Fender used two magnets per string. I'm not sure how necessary that is. Besides picking up the wide excursion of the strings, it also prevents the magnet from being directly under the string at the attack, which was the reason I have read for them doing that.

My first two prototypes used an arrangement like that, but with steel poles. Only I pushed them closer together so they actually touched. I was interested in one wide pole piece more than two.

[mick]

Hi BL

I tap my bobbins..but used to just screw the pole screws in without , if you use a good fitting screwdriver and keep the screw straight they do go in ok , I found the trick was once you got it started not to stop ,
I get my mags from allstar and likely pay a lot less than I would from AMF , allstar are pretty quick with postage etc , plus they answer my emails promptly most of the mag sellers are expensive if you buy small amounts though..
I have some bigger mags here , A5 8 x 20mm , not sure if you can use them but a guitar builder used some and made bass pickups so they may be ok..
Tell AMF to fuck off..greedy twats..email me if you are interested..

Mick

[black_labb]

those 8mmx20 seem like a good idea, i may just order some of them.

reguarding wether the 10x30mm mags are too large, are musicman pups not 10mmx20 or so? and have 2 of them in a humbucking config? or are they 8mm.


you guys are saying that it is overkill, but are you meaning the sound will suffer/stratitus, or are you thinking its just overkill?

[David King]

I'm saying it's overkill but it's true that the first couple of years of Music Man pickups had 19mm poles under the E and G string and longer, maybe 25mm poles under the A and D strings. The original diameter was nominally 3/8" which is about 9.5mm. They didn't use very many turns and I always thought that sounded a bit thin and nasal which is probably why they added that crappy active bass and treble control.
My bet is that Leo was really just trying to simplify the design to save a buck. I've heard other versions of the MM that sounded great. The Delanos with the alnico rods sound really nice.

[chevalij]

just out of curiousity, how would 1.20 per rod (the 100+ price before the hike) have compared to your sources? things like magnets and materials like this tend to be priced a fair bit higher in australia due to the small and relatively isolated market. on the other hand, basic wages are higher which is good in a way.

At $1.20, they would still be 3 to 20 times more expensive, depending on were I buy. Some may not believe it, but I have bought 5mm x 0.710 Alnico V at $0.07 each.

[David King]

I just ordered from Rob Paar at Allstar this morning and had to pay $.39 ea for 3/16" x .750" (4.8mm x 19mm) A5 rods. He's a talker, and has been in magnet manufacturing since 1981. They sell a lot of magnets to Fender among others...