New Mojotone Butyrate humbucker bobbins. How accurate are they ?

[big_teee]

If it is not a Real PAF, then it is a Counterfeit Knock-off.
I would be willing to say that most of us if we did a A-B Comparison.
Would find very little Difference in a $70 P/U Compared to a $300 Sooped Up Counterfeit Knock-Off!

B_T

[JGundry]

After all, it's more than just making a good pickup, it's the marketing that gets one the golden ring. There are ton of guys out there that can make a killer pickup w/o all the BS about butyrate and copper alloy, but then, what else is going to set apart the JGundry's and DaveStephens of the world, yep, MARKETING
(cough, cough, hyperbole)

[

Redhouse,

I am real up front about how what I make differs from others in the P.A.F. category. They are real details that customers can check out. Whether these details matter is up to the customer. Personally I think they matter so I let people know about them. I also make all of my own parts and also make them all in the USA. Both of these details are a rarity for the small maker. If you want to address details specifically that you think is B.S. that would be appreciated.

[RedHouse]

I only meant that since they're not "actual" PAF's, the forum brothers who are into them should be advertising them as "best PAF repro's" and not as actual PAF's, that's all. I am certainly not against any of the aforementioned souls specializing in this field, it's all good. It's just all the secret-PAF-society BS posts, "I know but ain't telling" gets ever-so-old, but YMMV.

{edit} JG, I'm not specifically pointing at you, only used you as an example since a few posts back this kind of thing was going on with both you and Possum, that's all, nothing more.

{edit2} meaning you both had something specific to debate, but neither actually posted the fact/spec/tidbit and both fell back on the 'ol "I know, but can't say".

[JGundry]

I only meant that since they're not "actual" PAF's, the forum brothers who are into them should be advertising them as "best PAF repro's" and not as actual PAF's, that's all. I am certainly not against any of the aforementioned souls specializing in this field, it's all good. It's just all the secret-PAF-society BS posts, "I know but ain't telling" gets ever-so-old, but YMMV.

{edit} JG, I'm not specifically pointing at you, only used you as an example since a few posts back this kind of thing was going on with both you and Possum, that's all, nothing more.

{edit2} meaning you both had something specific to debate, but neither actually posted the fact/spec/tidbit and both fell back on the 'ol "I know, but can't say".

Let me just say I don't even use PAF sticker on the back of my pickups. People know that I am making a repro. IMHO what I am making is really one of a kind when you consider the winding and parts accuracy. And I think I back it up pretty clearly but people can decide for themselves what is what easy enough.

Honestly I don't care much what Possum is up to. I lost interest long ago. I watched Geraldo unlock Al Capones vault and I vowed never to repeat that mistake again. Things like that are good TV for a little while but sooner or later you have to take a shit. In the case of Geraldo he took a big one.

[belwar]

Honestly I don't care much what Possum is up to. I lost interest long ago. I watched Geraldo unlock Al Capones vault and I vowed never to repeat that mistake again. Things like that are good TV for a little while but sooner or later you have to take a shit. In the case of Geraldo he took a big one.

hahaha nice

[RedHouse]

Let me just say I don't even use PAF sticker on the back of my pickups. People know that I am making a repro. IMHO what I am making is really one of a kind when you consider the winding and parts accuracy. And I think I back it up pretty clearly but people can decide for themselves what is what easy enough...

I'd have to agree with that, no offense intended JG.

[Fuzzy Logic]

Fuzzy logic: A mathematical logic that attempts to solve problems by assigning values to an imprecise spectrum of data in order to arrive at the most accurate conclusion possible. Fuzzy logic is designed to solve problems in the same way that humans do: by considering all available information and making the best possible decision given the input.


An attempt to reconstruct the main dimensions of a vintage P.A.F. humbucker - Part 1 - Introduction


Here we go.

A few posts back I mentioned that I would like to post my findings and thoughts regarding the dimensions of P.A.F. humbucker bobbins (the vintage ones, that is). The dimensions which I am attempting to reconstruct are based on given dimensions for string spacing, slug hole diameter, slug diameter, etc. and, for now, they do not include production tolerances.

There is one dimension which may be disputed at first sight and that is the dimension I use for the coil former width. Unfortuneately, I could not find a dimension for the coil former width which was derived from, or associated with, measurements on a vintage P.A.F. humbucker bobbin.

Regarding production tolerances. If one wants to recreate a (antique) plastic part by measuring it up, one also needs to know the production tolerances which were specified for that part at the time of production, or at least take this issue into account. I often read that the measurement results of vintage P.A.F. humbucker bobbins are all over the place, the results are all different, the results are not consistent, etc. Yes, I do believe that it is highly unlikely that the measurement results on 10 vintage bobbins would yield exactly the same results.

The main question here would be; are the different measurement results within the specified/assumed/expected production tolerances ?

Shrinkage after molding is not something which I have taken into account. Usually compensation for such shrinkage is taken care of in the mold construction process and thus not relevant in this exercise.

I do not claim that the dimensions I reconstruct should be considered as being THE correct dimensions for vintage P.A.F. humbucker bobbins or that they should be even considered as being accurate at all. Comments are invited to fix any inaccuracies in the stated/found dimensions.

The following dimensions were used to create a starting point:

1. String spacing: 1.9375" (31/16)"

2. Slug hole diameter: 0.1875" (3/16)"

3. Slug diameter: 0.187"
Ref: Exact PAF specs anyone? , source: WolfeMacleod
Ref: http://music-electronics-forum.com/t18441-2/ , source: JGundry

4. Coil former height (core): 0.2500" (4/16)"
Ref: PAF Mysteries and the Leesona 102 Winder - My Les Paul Forums , source: Throbak

Now, WolfeMacleod has indicated in this thread that the core height is supposed to be larger than 0.250", about 0.015" larger as he stated. I suspect that the height increase is probably something like (1/64)" resulting in a core height of 0.265". I have seen similar statements like this before:

Ref: Humbucker Question - AMPAGE Archive , source: Matt
Ref: Vintage PAF - the missing link - AMPAGE Archive , source: Mike Turk

For now I will use 0.250" for the core height, also because I will attempt to prove a bit later on that the P.A.F. humbucker slug bobbin appears to be a derivative of a P90 bobbin. In case the core height should be indeed 0.265" then this is no real problem. This does only affect the bobbin height, the other dimensions of the bobbin are not affected by this.

5. Coil former width (core): 0.2500" (4/16)"
Ref: PAF Bobbin dementions , source: RedHouse

Several core widths were reported in that thread for non-vintage P.A.F. style bobbins ranging from 0.247" to 0.259". Now, the following is a bit arbitrary but I divided all the reported values by 8 in order to see what these dimensions would look like when expressed as a multiple of (1/8)". The results were consistently very close to a factor 2 so I decided that choosing (1/4)" for the core width would not be an unreasonable thing to do, also because I will attempt to prove a bit later on that the P.A.F. humbucker slug bobbin appears to be a derivative of a P90 bobbin.

6. Magnet width: 0.5000" (8/16)"
Ref: no reference here, there are many references to this dimension to be found all over the internet.

7. Screw keeper bar width: 0.1875" (3/16)"
Ref: Exact PAF specs anyone? , source: WolfeMacleod

For the purpose of this exercise I will use 0.1875" as being the dimension for the screw keeper bar width. I have no reason to doubt the dimension of 0.190" which was reported by WolfeMacleod. However, it is highly probable that these screw keeper bars were made from standard (3/16)" flatstock. I will assume that the difference between 0.1875" and 0.190" is due to production tolerances in the manufacturing process.

Given the fact that holes are punched through a relatively soft metal, my guess is that the amount of deformation of the metal bar due to the punching process is dominant in the total value of the production tolerance.

Next: Part 2 - Slug bobbin, the calculations

[Fuzzy Logic]

An attempt to reconstruct the main dimensions of a vintage P.A.F. humbucker - Part 2 - Slug bobbin, the calculations


The width of an individual P.A.F. humbucker slug or screw bobbin should ideally be identical to the distance between the centers of the slug and screw bobbin:

Width of bobbin = (slug hole diameter/2) + magnet width + (screw keeper bar width/2)
Width of bobbin = (0.1875"/2) + 0.5000" + (0.1875"/2)
Width of bobbin = (0.1875"/2) + 0.5000" + (0.1875"/2)
Width of bobbin = 0.09375" + 0.5000" + 0.09375"
Width of bobbin = 0.6875" (11/16)"

Now we can proceed to determine other dimensions. I will start with the slug bobbin.

The maximum winding depth along the length of the slug bobbin can be defined as:
((width of bobbin) - (width core))/2

Maximum winding depth (l): (0.6875" - 0.25000")/2
Maximum winding depth (l): 0.4375"/2
Maximum winding depth (l): 0.21875" (7/32)"

Given the diameter of the slug hole and the width of the core, the minimum thickness of the butyrate between the perimeter of the slug holes and the outside of the core can be defined as:
((core width) - (slug hole diameter))/2

Minimum butyrate thickness core: (0.2500" - 0.1875")/2
Minimum butyrate thickness core: (0.0625")/2
Minimum butyrate thickness core: 0.03125" (1/32)"

I now assume that the minimum thickness of the butyrate between the perimeter of the slug holes and the outside of the core does not change along the whole perimeter of the core. The length of the core can now be defined as:
(butyrate thickness) + (diameter slug hole)/2 + string spacing + (diameter slug hole)/2 + (butyrate thickness)

Coil former length (core): 0.03125" + (0.1875"/2) + 1.9375" + (0.1875"/2) + 0.03125"
Coil former length (core): 0.03125" + 0.09375" + 1.9375" + 0.09375" + 0.03125"
Coil former length (core): 2.1875" (35/16)"

Assuming that the maximum winding depth along the length of the slug bobbin is equal to the maximum winding depth along the width of the slug bobbin, the length of the slug bobbin can now be defined as:
winding depth (w) + length core + winding depth (w).

Length slug bobbin: 0.21875" + 2.1875" + 0.21875"
Length slug bobbin: 2.6250" (42/16)"

Now, as for the height of the bobbin. Back in 2008 there was a post which listed the measurement results on several different bobbins (non-vintage).

Ref: PAF Bobbin dementions

Several bobbin heights were reported in that thread ranging from 0.367" to 0.380". Now, again, the following is a bit arbitrary but I divided all the reported values by 8 in order to see what these dimensions would look like when expressed as a multiple of 1/8". The results were consistently very close to a factor 3 so I decided that choosing (3/8)" for the bobbin height would not be a unreasonable thing to do.

A bobbin height of 0.375" implies a butyrate thickness of a flange of the bobbin of: (height bobbin - height core)/2

Butyrate thickness flange: (0.375" - 0.250")/2
Butyrate thickness flange: 0.0625" (1/16)"


Next: Part 3 - Slug bobbin, the summary

[Fuzzy Logic]

An attempt to recreate the main dimensions of a vintage P.A.F. humbucker - Part 3 - Slug bobbin, the summary


Summary of the reconstructed (vintage) P.A.F. humbucker slug bobbin presumed main dimensions (see also parts 1 and 2 above):

String spacing : 1.9375" or (31/16)"
Slug hole diameter : 0,1875" or (3/16)"
Slug bobbin length : 2.6250" or (42/16)"
Slug bobbin width : 0.6875" or (11/16)"
Slug bobbin height : 0.3750" or (6/16)"
Slug core length : 2.1875" or (35/16)"
Slug core width : 0.2500" or (4/16)"
Slug core height : 0.2500" or (4/16)"
Maximum winding depth slug bobbin: 0.21875" or (7/32)"
Butyrate thickness flange : 0.0625" or (1/16)"

Now, these are the dimensions without production tolerances taken into account. That is, production tolerances due to tolerances in the mold and tolerances due to the whole molding process itself. It does not seem to be unreasonable to assume a production tolerance on the dimensions of +/- 0.005".

Ref: Plastics Today

The following may be a bit questionable... In order to determine the range of variation in the various slug bobbin dimensions when taking a production tolerance of +/- 0.005" into account, a quick and dirty way is to just add/substract this tolerance to/from the dimensions as above. This is more intended for illustrative purposes. A true assessment on a design for tolerance issues should be done in a more accurate/proper fashion.

String spacing : 1.9425" to 1.9325"
Slug hole diameter : 0.1925" to 0.1825"
Slug bobbin length : 2.6300" to 2.6200"
Slug bobbin width : 0.6925" to 0.6825"
Slug bobbin height : 0.3800" to 0.3700"
Slug core length : 2.1925" to 2.1825"
Slug core width : 0.2550" to 0.2450"
Slug core height : 0.2550" to 0.2450"
Maximum winding depth slug bobbin: 0.21875" or (7/32)" , assuming an equal distribution of tolerances
Butyrate thickness flange : 0.0675" to 0.0575"


Next: Part 4 - Screw bobbin, the calculations

[Guitarist]

Just lost a lengthy opinionated writeup trying to attach something.

I was wondering, why not return to larger 38 guage wire? We insist on such "quality" everywhere else and that Lollar Rayo pickups sounds amazing, but would be nice with a tap there + a hefty extra overwind of say 35%.
My solo tones are always darkened a bit so a 7K sound with a 10K tap tone might rule under finger.

[Fuzzy Logic]

An attempt to reconstruct the main dimensions of a vintage P.A.F. humbucker - Part 4 - Screw bobbin, the calculations


Some dimensions of a screw bobbin are reported to differ from the dimensions of the slug bobbin. Although I have come across a number of references regarding this issue I will list only one:

Ref: Premier Guitar magazine has the latest in guitar information and equipment along with music interviews, product reviews and much more. (at the bottom of the article)

As it appears, the coil former (core) of a screw bobbin has different dimensions when compared to the dimensions of the core of a slug bobbin.

I am now going to make the following assumptions:

1. The width of a screw bobbin is identical to the width of a slug bobbin (0.6875" (11/16)") ;

2. The length of a screw bobbin is identical to the length of a slug bobbin (2.6250" (42/16)") ;

3. The minimum thickness of the butyrate between the perimeter of the screw holes and the outside of the screw core is identical to the minimum thickness of the butyrate between the perimeter of the slug holes and the outside of the slug core (0.03125" (1/32)") ;

4. The winding depth along the length of the core is identical to the winding depth along the width of the core ;

5. The height of the screw bobbin is identical to the height of the slug bobbin (0.3750" (6/16)") ;

6. The butyrate thickness of a flange of a screw bobbin is identical to the butyrate thickness of a flange of a
slug bobbin (0.0625" (1/16)") ;

7. The core height of a screw bobbin is identical to the core height of a slug bobbin (0.2500" (4/16)").

The dimensions for the screw bobbin which still need to be reconstructed are: winding depth, core width and core length.

Ok.

It may be clear, a pole screw has different dimensions than a slug. On itself, steel/iron alloy composition aside, the pole screw appears to be nothing special. It is a nickel plated 5-40 machine screw with a slotted fillister head and having a length of 0.75". I am not going to add a specific reference here to confirm a source of this information. The amount of topics here dealing with P.A.F. type pole screws is frightening to say the least, so one should have no trouble finding a confirmation about the type of pole screw which is to be used on the screw side of a P.A.F. humbucker.

The head of this 5-40 machine screw is the part of the screw which has the largest diameter and inserts partly in the
core of the screw bobbin. The dimension for the diameter of the fillister head of 5-40 machine screws is stated as ranging from 0.187" to 0.205".

Ref: Fillister Head Screw Style - The Thelen Channel

For now I have no reason to assume that these dimensions were significantly different in the 50s.

The pole screw hole in the screw bobbin has a diameter of approximately 0.200" (stated as "The screw hole for the head is .200" maybe a little larger").

Ref: Butyrate Bobbins - Page 2 , source: JGundry

I did choose a diameter for the pole screw hole of 0.203125" (13/64)". As a side note; the mean diameter of the fillister head of a 5-40 machine screw is (0.187" - 0.205")/2 = 0.196". When the pole screw hole diameter is (13/64)" and a production tolerance of +/- 0.005" is assumed, then a pole screw having a mean head size of 0.196" will still fit in the pole screw hole in those cases where the tolerance is on the minus side of the spectrum (0.203125" - 0.005" = 0.198125").

The width of the screw core now can be defined as:
minimum butyrate thickness core + diameter screw hole + minimum butyrate thickness core

Width screw core: 0.03125" + 0.203125" + 0.03125"
Width screw core: 0.265625" (17/64)"

The length of the screw core can be defined as:
minimum butyrate thickness core + (diameter screw hole)/2 + string spacing + (diameter screw hole)/2 + minimum butyrate thickness core

Length of screw core: 0.03125" + (0.203125"/2) + 1.9375" + (0.203125"/2) + 0.03125"
Length of screw core: 0.03125" + 0.1015625" + 1.9375" + 0.1015625" + 0.03125"
Length of screw core: 2.203125" (141/64)"

The maximum winding depth can be defined as: (width bobbin - width screw core)/2

Maximum winding depth screw bobbin: (0.6875" - 0.265625")/2
Maximum winding depth screw bobbin: 0.421875"/2
Maximum winding depth screw bobbin: 0.2109375" (27/128)"


Next: Part 5 - Screw bobbin, the summary

[Fuzzy Logic]

An attempt to recreate the main dimensions of a vintage P.A.F. humbucker - Part 5 - Screw bobbin, the summary


Summary of the reconstructed (vintage) P.A.F. humbucker screw bobbin presumed main dimensions (see also parts 1-4 above):

String spacing : 1.9375" or (31/16)"
Screw hole diameter : 0.203125" or (13/64)"
Screw bobbin length : 2.6250" or (42/16)"
Screw bobbin width : 0.6875" or (11/16)"
Screw bobbin height : 0.3750" or (6/16)"
Screw core length : 2.203125" or (141/64)"
Screw core width : 0.265625" or (17/64)"
Screw core height : 0.2500" or (4/16)"
Maximum winding depth screw bobbin: 0.2109375" or (27/128)"
Butyrate thickness flange : 0.0625" or (1/16)"

Now, these are the dimensions without production tolerances taken into account. That is, production tolerances due to tolerances in the mold and tolerances due to the whole molding process itself. It does not seem to be unreasonable to assume a production tolerance on the dimensions of +/- 0.005".

Ref: Plastics Today

Again, the following may be a bit questionable... In order to determine the range of variation in the various screw bobbin dimensions when taking a production tolerance of +/- 0.005" into account, a quick and dirty way is to just add/substract this tolerance to/from the dimensions as above. This is more intended for illustrative purposes. A true assessment on a design for tolerance issues should be done in a more accurate/proper fashion.

String spacing : 1.9425" to 1.9325"
Screw hole diameter : 0.20813" to 0.19813"
Screw bobbin length : 2.6300" to 2.6200"
Screw bobbin width : 0.6925" to 0.6825"
Screw bobbin height : 0.3800" to 0.3700"
Screw core length : 2.20813" to 2.19813"
Screw core width : 0.27063" to 0.26063"
Screw core height : 0.2550" to 0.2450"
Maximum winding depth screw bobbin: 0.21094" or (27/128)"
Butyrate thickness flange : 0.0675" to 0.0575"


Next: Part 6 - A P.A.F. humbucker slug bobbin and P90 bobbin connection ?

[RedHouse]

I see your alias serves you well.

[David Schwab]

I, on the other hand, am just trying to figure out certain details or have details confirmed for my own personal amusement and education on the subject of the puzzle called P.A.F.

The way I look at it is they are pretty normal pickups, with a lot of mystique piled on them. They are also inconsistent. The little details that people agonize over where probably not even a consideration when Gibson tooled up and started making them. All they probably cared about as far as alloys was which screws they could get in bulk at a price they liked, etc. Seth Lover had certain ideas, but they were never put into production. And even his prototypes started out as cut down P-90 bobbins and other things he cobbled together by hand. Did the production pickups match his? Probably not. Tim Shaw had the same problem when Gibson asked him to recreate the PAFs. They just wouldn't pay for certain details that they didn't think were important. Gibson still acts this way when it comes to reissues. They reissued the RD Standard bass and put in Jazz bass pickups!

Now on the other hand, if you are trying to reproduce a certain pickup from that era, then you do have to do a little research, and then you can probably get an accurate copy of that particular pickup, or maybe an average of a handful of pickups. I'm not sure how many are sampled when these various reproductions were made.

But to give an example of all the various tones you can get from a PAF, look at the various PAF style pickups from Duncan. There are at least 4 that I can think of off the top of my head that are some version of a PAF. Frank would know better. I'm sure this was from Seymour dissecting samples, as he has done with many pickups over the years. Then another approach is what DiMarzio did, where they found new ways to coax similar tones without matching the parts.

I had a set of very early patent label pickups, probably from the first year they had labels, and were available from Gibson, that were removed from an old gold top that had been converted from P-90s to humbuckers. The owner removed them and replaced them with the DiMarzio PAFs when they first came out in the 70s. He liked the DiMarzios better. I had the Gibsons in my old Sekovia LP copy, and they were nice, but were absolutely not something that made you say "OMG! What pickups are those?" They just sounded like what all the guitars back then sounded like. And that's a lot what the guitars now sound like. They sound like guitars.

IMO everything else is hype. That's not to dismiss makers who make PAF repros. And I'd bet the repros sound better, just as the DiMarzios did.

[the great waldo]

The way I look at it is they are pretty normal pickups, with a lot of mystique piled on them. They are also inconsistent.
Now on the other hand, if you are trying to reproduce a certain pickup from that era, then you do have to do a little research, and then you can probably get an accurate copy of that particular pickup, or maybe an average of a handful of pickups. I'm not sure how many are sampled when these various reproductions were made.

I had a set of very early patent label pickups, probably from the first year they had labels, and were available from Gibson, that were removed from an old gold top that had been converted from P-90s to humbuckers. The owner removed them and replaced them with the DiMarzio PAFs when they first came out in the 70s. He liked the DiMarzios better. I had the Gibsons in my old Sekovia LP copy, and they were nice, but were absolutely not something that made you say "OMG! What pickups are those?" They just sounded like what all the guitars back then sounded like. And that's a lot what the guitars now sound like. They sound like guitars. IMO everything else is hype. That's not to dismiss makers who make PAF repros. And I'd bet the repros sound better, just as the DiMarzios did.

Hi David

I had a similar experience with a late 50īs les paul in the early 80īs that had a broken pickup. I fitted a Dimarzio paf in itīs place and it sounded great and fitted with the existing pickup well. I even took the liberty of trying the pickups swapped around and couldīnt precieve a difference between them (I must say that it was a nice guitar anyway) Luckily in those days old Les Pauls were treated as nice guitars and not holy relics. After Paul Kossof there was quite a spate of guys bringing old Les Pauls to get the tops stripped to natural, imagine doing that now!!

Cheers

Andrew