Ash at Oil City answers pickup questions:

jaymenon

Is it true Ash - that with a symmetrically wound humbucker, the slug coil has more inductance (is more powerful)?

So there is some integral ‘asymmetry’ due to the fact that one coil is screw and the other coil is slug?

OilCityPickups

jaymenon said:

Is it true Ash - that with a symmetrically wound humbucker, the slug coil has more inductance (is more powerful)?

So there is some integral ‘asymmetry’ due to the fact that one coil is screw and the other coil is slug?

You can see it on a meter - but if you can hear it - you are a bat. :-)  You can hear the lack of asymmetry when it's caused by a difference in hundreds of turns, which directly affects that's coil's respective volume but remember it's iron mass that causes inductance in this case, and while the pole screws are smaller and lighter, they are coupled into a 'keeper bar' or 'pole shoe' on the screw side that ups that mass considerably. There is ultimately very little difference and none that you can hear unless you are expecting to :-) 

There is nothing wrong with matched coils if that is the tone you want mind.   

earwighoney

OilCityPickups said:

earwighoney said:

@OilCityPickups I saw you made a Thunderbird spec pickup in a HB case for someone here.  Sorry to ask but what is the difference between that pickup and a Firebird (in a HB case).  Does a Thunderbird pickup have longer alnico blade magnets than a FB?

Yep Thunderbirds use normal sized 63mm humbucker magnets but on their sides in the middle of the bobbins. My HB sized ones use shorter sixties Gibson style 58mm magnets to fit under the covers.  

These seem pretty cool, maybe what I am after!  Would it be possible to come back at some point with an order for this and something else?

OilCityPickups

earwighoney said:

OilCityPickups said:

earwighoney said:

@OilCityPickups I saw you made a Thunderbird spec pickup in a HB case for someone here.  Sorry to ask but what is the difference between that pickup and a Firebird (in a HB case).  Does a Thunderbird pickup have longer alnico blade magnets than a FB?

Yep Thunderbirds use normal sized 63mm humbucker magnets but on their sides in the middle of the bobbins. My HB sized ones use shorter sixties Gibson style 58mm magnets to fit under the covers.  

These seem pretty cool, maybe what I am after!  Would it be possible to come back at some point with an order for this and something else?

Of course - I may take them into my normal pickup range anyway .... I've been playing with a pair of late and I really like them myself. 

Seziertisch

Ash, what impact does an air coil have on the sound of a pickup compared to using a bobbin?

Say you had a PAF style pickup and you wound it to a certain spec with air coils instead of bobbins, how would you expect it to differ in sound from  a pickup wound to the same spec using bobbins?

Cheers.

Everythingon10

Can you explain how a triple-coil design, like one of your nosieless P90s, is hum cancelling?

I have a Strat with an RWRP middle pickup and a button to add the neck pickup to any position on the selector switch. If you turn on all three pickups at once, it's as noisy as one single coil by itself. I can't get my head around how three coils can equal silence, or why a two coil design can't achieve this tonal result.

OilCityPickups

A two coil design can achieve a silent result ... hence ordinary humbuckers. 

Let me start at the beginning. What makes hum cancelling pickups hum cancelling is having equal amounts of wire wound on bobbins with opposite magnetic polarities. Now with your Strat when you turn on that third coil you have a two to one ratio of wire two coils with much more wire collectively than the other - so you won't get hum cancelling. 
You can have a humbucker with any number of coils you fancy so long as the number of turns at one polarity match the number of turns of the other you get hum cancelling. So for the sake of example you could have 15000 turns spread over three coils 'south up' and a fat coil with 15000 turns on it only 'north up ... and you have a four coil humbucker.
A three coil humbucker just has the same amount of wire on one coil as the sum of the other two ... hey presto. 

The reason for using the triple coil design is in keeping the collective coil shape as close to that of a P90 as possible ... because coil shape is a major part of tone.  

Seziertisch

Seziertisch said:

Ash, what impact does an air coil have on the sound of a pickup compared to using a bobbin?

Say you had a PAF style pickup and you wound it to a certain spec with air coils instead of bobbins, how would you expect it to differ in sound from  a pickup wound to the same spec using bobbins?

Cheers.

You might have missed this one, Ash. Thanks.

OilCityPickups

Seziertisch said:

Seziertisch said:

Ash, what impact does an air coil have on the sound of a pickup compared to using a bobbin?

Say you had a PAF style pickup and you wound it to a certain spec with air coils instead of bobbins, how would you expect it to differ in sound from  a pickup wound to the same spec using bobbins?

Cheers.

You might have missed this one, Ash. Thanks.

Currently been in bed for four days with what would appear to be the worst case of Covid I've had to date ... really not doing too well ... will respond when I can  

OilCityPickups

Seziertisch said:

Seziertisch said:

Ash, what impact does an air coil have on the sound of a pickup compared to using a bobbin?

Say you had a PAF style pickup and you wound it to a certain spec with air coils instead of bobbins, how would you expect it to differ in sound from  a pickup wound to the same spec using bobbins?

Cheers.

You might have missed this one, Ash. Thanks.

Okay so between coughing bouts and pain killers ... 
a proper air coil has a roughly circular or oval cross section and is almost the most scatter wound and loose a coil can be within a pickup ... it's not even the same as winding around a magnet, as the coil when taped up is a sort of floppy, amorphous  doughnut that just sits around the magnet in the centre. Old air coils were seldom potted though some like Burns did use self amalgamating wire from time to time.
All this means it's actually impossible to put as much wire of a given gauge in an air coil of a comparable size to a normally wound bobbin. Generally air coils are low to very low output and use fine wire (an exception being Burns)  - the advantage being a very warm and 'woody' tone - which is great because some of the best jazz guitar pickups are air coils or versions of air coils.
Winding an air coil humbucker is certainly possible, though by necessity it's much larger than a conventional humbucker. On a specially made, custom Jazz box one would do wonders ... and if anybody want's to ask me to make one for that ... great, but it would almost certainly have to be a one off form factor. 

NickBotfield

Apologies if this sounds massively dumb and basic!

How does a pickup transfer the acoustic sound of a guitar to the amp?  As I understand it the ferrous mass of the strings passing through the magnetic field of the pickup creates an electrical current.  How do all the non-magnetic (mostly wooden) bits of a guitar have an effect on this signal coming out of the guitar?

earwighoney

OilCityPickups said:

Seziertisch said:

Seziertisch said:

Ash, what impact does an air coil have on the sound of a pickup compared to using a bobbin?

Say you had a PAF style pickup and you wound it to a certain spec with air coils instead of bobbins, how would you expect it to differ in sound from  a pickup wound to the same spec using bobbins?

Cheers.

You might have missed this one, Ash. Thanks.

Currently been in bed for four days with what would appear to be the worst case of Covid I've had to date ... really not doing too well ... will respond when I can  

Sorry to this chap, good luck with your recovery.

OilCityPickups

NickBotfield said:

Apologies if this sounds massively dumb and basic!

How does a pickup transfer the acoustic sound of a guitar to the amp?  As I understand it the ferrous mass of the strings passing through the magnetic field of the pickup creates an electrical current.  How do all the non-magnetic (mostly wooden) bits of a guitar have an effect on this signal coming out of the guitar?

Not dumb at all:
 This is due to the fact that all but some fully epoxy potted guitar pickups are microphonic - even at levels that don't translate handling noise - but do translate resonances from the body into electrical signals.  The mechanism for this is simple, a guitar pickup is exactly the same 'gadget' as a vocal microphone except it has no diaphragm. In a guitar pickup every single loop of wire, magnet and screw has a small amount of movement, and that movement acts like a diaphragm. This is so pronounced on some pickups you can turn up your amp and shout into your pickups and your voice will be audible through your speakers!  

Now of course too much microphony is bad as you get squeal and feedback - this is why we pot pickups ... however not too much so as to kill off the 'good' microphony. 

NickBotfield

OilCityPickups said:

NickBotfield said:

Apologies if this sounds massively dumb and basic!

How does a pickup transfer the acoustic sound of a guitar to the amp?  As I understand it the ferrous mass of the strings passing through the magnetic field of the pickup creates an electrical current.  How do all the non-magnetic (mostly wooden) bits of a guitar have an effect on this signal coming out of the guitar?

Not dumb at all:
 This is due to the fact that all but some fully epoxy potted guitar pickups are microphonic - even at levels that don't translate handling noise - but do translate resonances from the body into electrical signals.  The mechanism for this is simple, a guitar pickup is exactly the same 'gadget' as a vocal microphone except it has no diaphragm. In a guitar pickup every single loop of wire, magnet and screw has a small amount of movement, and that movement acts like a diaphragm. This is so pronounced on some pickups you can turn up your amp and shout into your pickups and your voice will be audible through your speakers!  

Now of course too much microphony is bad as you get squeal and feedback - this is why we pot pickups ... however not too much so as to kill off the 'good' microphony. 

What a brilliant explanation, thanks so much Ash!  Massive lightbulb moment!

OilCityPickups

NickBotfield said:

OilCityPickups said:

NickBotfield said:

Apologies if this sounds massively dumb and basic!

How does a pickup transfer the acoustic sound of a guitar to the amp?  As I understand it the ferrous mass of the strings passing through the magnetic field of the pickup creates an electrical current.  How do all the non-magnetic (mostly wooden) bits of a guitar have an effect on this signal coming out of the guitar?

Not dumb at all:
 This is due to the fact that all but some fully epoxy potted guitar pickups are microphonic - even at levels that don't translate handling noise - but do translate resonances from the body into electrical signals.  The mechanism for this is simple, a guitar pickup is exactly the same 'gadget' as a vocal microphone except it has no diaphragm. In a guitar pickup every single loop of wire, magnet and screw has a small amount of movement, and that movement acts like a diaphragm. This is so pronounced on some pickups you can turn up your amp and shout into your pickups and your voice will be audible through your speakers!  

Now of course too much microphony is bad as you get squeal and feedback - this is why we pot pickups ... however not too much so as to kill off the 'good' microphony. 

What a brilliant explanation, thanks so much Ash!  Massive lightbulb moment!

You are most welcome