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Posted

Ok folks, I've got to shoot off to work in a minute so I'll have to keep this brief!

I'm planning on putting 3 Lace Alumitone pickups in a guitar, in-series. One volume, one tone.

So what I want to have is three individual switches (SPST? SPDT? Help!), each effectively acting as on-off for each pickup.

I've read that in-series wiring means a loss (to some extent) of treble frequencies. Should I compensate for this by using 500k pots and .22 caps to brighten the sound instead of the 'usual' 250k/.47 combination for pickups of this type?

I'd be interested if anyone knows what values the pots/caps in a Brian May guitar have...

Any thoughts will be much appreciated!

And before anyone asks, yes I am set on the Alumitones! Either that or I'd be going for Q-Tuners which I really can't afford...

Thanks again folks,

Chris :D

Posted
I'd use whatever combo Lace recommends for those pickups. They're completely different than the original pickups in the Red Special.

Unfortunately Lace doesn't have any recommendations on their website, and if they did they'd probably pertain to strat-type parallel wiring setups. Based on that I'd just use the 'Fender' standard pots/caps, as I said above.

The reason I mention the red special, and am asking for advice here in general, is that I'm planning on wiring up the pickups in-series, something I've not done before. I know what to expect in terms of sound from these pickups. What I don't know is how much treble I'll lose by wiring in series.

I basically want to know if the bleed-off of treble caused by wiring pickups this way warrants using 500k pots and/or brighter sounding caps. I was thinking of compromising and going for a 500k/.47 combination, which in my messed up brain would lead to the ability to roll-off a lot of treble with the tone pot if need-be, but less loss of treble through the pots.

Also, what type of switches to use for the circuit is an issue. I could undoubtely stumble on it someplace online, but it's nice to have someone to verify it 'in-person'!

Thanks again for any help,

Chris

Posted

Just a thought-- many of Brian May's characteristic tones were very smooth and without high-end. Losing some treble probably contributed to this. When you want the brightness, you just use single or 2 of the pickups. With all 3 in series, you get the *benefit* (not the disadvantage) of a very different tone. :D

Other than that, I unfortunately don't have proper actual practical advice for your question.

Posted
Just a thought-- many of Brian May's characteristic tones were very smooth and without high-end. Losing some treble probably contributed to this. When you want the brightness, you just use single or 2 of the pickups. With all 3 in series, you get the *benefit* (not the disadvantage) of a very different tone. :D

Other than that, I unfortunately don't have proper actual practical advice for your question.

Interesting point, made me look at this whole endeavour somewhat differently!

Well, in any case I've ordered my components and I'm going to try and piece it all together from a 'Brian May' diagram I found online. I've gone for three SPDT switches for the pickup on/offs, 500k pots and a .47 cap. I'll just see how it goes, I guess!

  • 3 weeks later...
Posted

Ok folks, finally got the pickups from the US and put this thing together...

I've based it on this diagram, without the phasing switches...

brianmay.jpg

I've still got a couple of issues though.

Firstly, when I'm not touching the strings/bridge I get a hum/buzz.

Secondly, when I touch either the middle or bridge pickup (or their mounting screws) this creates a kind of high pitch squeal like feedback.

Neither is great. I have a theory that the neck pickup is exempt from this annoying microphonicness because it's toggle switch is directly grounded to the jack, as in the diagram. Is there a way to ground the other switches without screwing up the circuit? That is, if that is indeed to blame...

Any thoughts/advice appreciated!

Thanks again,

Chris

PS The Alumitones sound LOVELY.

Posted

The bodies of the switches need to be grounded too, preferably to a common point or "star". If you're using single-coil pickups then it's not surprising that you're getting some hum when you're not touching the strings, but it sounds like you have some major ground loopage going on if the bodies of the other switches and the pots aren't grounded.

Posted
...I have a theory that the neck pickup is exempt from this annoying microphonicness because it's toggle switch is directly grounded to the jack, as in the diagram. Is there a way to ground the other switches without screwing up the circuit? That is, if that is indeed to blame...

hi Chris, i think you theory is right.

but i think it might only explain part of the problem.

if the frame of the pickup is connected to the violet wire, you will have this problem with all pickups, except the one at the top of the drawing.

IF THIS IS THE PROBLEM, you will also have this problem with the pickup at the top of the drawing if you put it out of phase.

if that is the case, you need to find a way to separate that end of the coil from the frame. then run a separate wire from the frame, directly to ground.

i also have some thoughts on an improvement of your pickup switching. but let's address the ground issue first, right?

cheers,

unk

Posted

I'd have to listen to know how excessive the hum is, but it's very common indeed for guitars to hum more when you're not touching the strings. The very reason that bridges (and therefore strings) are grounded is to get the benefit of more silence when you're touching them. I don't know the science behind it... someone tried to tell me it's because you add yourself to the ground as an additional "shield", but I dunno about that. I just know that touching the strings on any guitar but the most seamlessly shielded ones will reduce hum.

Posted

Crafty - The bodies of the switches are plastic, so where do I solder the ground wire?

Unk - Alumitone pickups are kind of odd, there's not really a 'coil' or a 'frame' as such, the whole thing kind of is the coil. The weird part is instead of springs on the pickup mounting screws there are rubber sheaths/tubes that slide onto the screws. I think these might be helping to shield the screws from the pickup's magnetic field. Thing is I cut some of those sheaths down so maybe they're not covering the exposed part of the screw and thus creating the squeal. Again, I think the neck pickup may be exempt here... so maybe that's another reason?

GregP- The hum is serious. It's a full on buzzing. Nothing like any of my other guitars, including my old Squier tele. At least the hum was continuous, didn't come and go when I moved my hand. Plus, alumitones are meant to be 'silent'...

Thanks to all for their advice! Stay with me.

Chris

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