Firebird PU small metal top plate - necessary?

[jrdamien]

This is the answer of Peter Schultz from Stewmac

Thank you for contacting us. The small steel plate across the top of a Firebird Mini Humbucker helps to focus the vibrations of the "B" string. This causes the "B" string to have a slightly higher output relative to the other strings.

Using one of these Firebird Mini Humbuckers, you will notice that the "B" string sounds more compared to the other strings. This small steel plate is part of the vintage technical specifications that contribute to the vintage sound of these pickups.

Ummmm...

Of all of them I have made, the only difference has been that the field is shunted on the B & G strings. I now make them without.

I just did a bridge FB for a guy and he wanted it "pure vintage" so I cut and applied the little plate. He called back right after picking it up complaining there he couldn't here the B & G string as well.

[Zhangliqun]

Regarding the original question: FWIW, I've made them both ways and I can't hear a difference so I stopped bothering with it.

[charrich56]

As an aside from the aside, the GFS Gold Foil Alnico V (non P-90) humbuckers are built like "regular" humbuckers, with bobbins of the same dimensions. DCRs of 5.4K (neck) and 6.0K (bridge) of 43AWG puts them in the ballpark of 3000 turns/coil. I know because GFS is phasing out the 4-conductor fixed solder leads and replacing them with 3-conductor detachable leads; I wanted the option of wiring the coils in parallel, so....


By "variable rez tone control", do you mean a rotary switch with a bunch of capacitors?

-rb

Even better. I use a buffer to bootstrap a capacitor through a pot, and can continuously vary the load capacitance, therefore the pickup resonant frequency, over more than 1 1/2 octaves. Beats the pants off a regular tone control. The buffer allows independent setting of pickup load resistance to control Q. It works very nicely. Here's the thread on it: http://music-electronics-forum.com/t43081/

The "variable rez tone control" really stands for "variable resonant frequency tone control." I don't have a cuter name for it yet.

I designed an open-sourced 2-JFET buffer that works well with this approach. It's close to the end of the thread. There will be a commercial SMT version of this buffer very soon.

-Charlie

[rjb]

It seems we're approaching a consensus about the Stew-Mac guy...

[copperheadroads]

The response from the Stew-Mac guy sounds like the opposite of what one would expect

I've had conversations with them ....Trust me they are not winders .

[rjb]

BTW just as an aside, the GFS Gold Foil P-90 humbuckers actually look like a classic Firebird HB design (minus the little metal piece in question) when one peeks under the gold foil on top....

As an aside from the aside, the GFS Gold Foil Alnico V (non P-90) humbuckers are built like "regular" humbuckers, with bobbins of the same dimensions. DCRs of 5.4K (neck) and 6.0K (bridge) of 43AWG puts them in the ballpark of 3000 turns/coil. I know because GFS is phasing out the 4-conductor fixed solder leads and replacing them with 3-conductor detachable leads; I wanted the option of wiring the coils in parallel, so....

I'm going to throw my set into an Epiphone I have handy, with a variable rez tone control, and see if they can make good sounds.

By "variable rez tone control", do you mean a rotary switch with a bunch of capacitors?

-rb

[rjb]

Somebody else has an opinion ?

To put it undiplomatically, my opinion is that the Stew-Mac guy is all wet.
So far, there seems to be a consensus about the purpose of the piece of metal, if not about the Stew-Mac guy.

-rb

[marcfrom]

I dunno. Post #2 is still my best guess.

-rb

Especially the "Try it".

Somebody else has an opinion ?

[charrich56]

I dunno. Post #2 is still my best guess.

-rb

The response from the Stew-Mac guy sounds like the opposite of what one would expect by partially "shunting" the magnetic field under the B string with the piece of metal, and reducing output. I do appreciate the asking, though.

BTW just as an aside, the GFS Gold Foil P-90 humbuckers actually look like a classic Firebird HB design (minus the little metal piece in question) when one peeks under the gold foil on top. Also, the "polepiece" screws are probably stainless and definitely non-magnetic, as verified by my Spin Doctor gaussmeter, therefore they are there completely for looks. The polepieces aren't necessarily bad, I'm just commenting on what they are. I'm going to throw my set into an Epiphone I have handy, with a variable rez tone control, and see if they can make good sounds.

[rjb]

But does the ferrous plate do not increase the magnetics field around itself as a Tele bridge pickup?

I dunno. Post #2 is still my best guess.

-rb

[marcfrom]

Hunh.
Historically, pickups always had a problem with the "B" string having higher output- because the plain steel "B" string was thicker than the core of the wound "G" string. That's why Gibson started notching "Charlie Christian" polepieces below the "B" string in 1938.

https://en.wikipedia.org/wiki/Gibson...tian_pickup.22<

-rb

yes it's true even on the Strat Pickups the B rod is more away from the string.

But does the ferrous plate do not increase the magnetics field around itself as a Tele bridge pickup?

[rjb]

The small steel plate across the top of a Firebird Mini Humbucker helps to focus the vibrations of the "B" string. This causes the "B" string to have a slightly higher output relative to the other strings.

Hunh.
Historically, pickups always had a problem with the "B" string having higher output- because the plain steel "B" string was thicker than the core of the wound "G" string. That's why Gibson started notching "Charlie Christian" polepieces below the "B" string in 1938.

https://en.wikipedia.org/wiki/Gibson...tian_pickup.22

-rb

[marcfrom]

This is the answer of Peter Schultz from Stewmac

Thank you for contacting us. The small steel plate across the top of a Firebird Mini Humbucker helps to focus the vibrations of the "B" string. This causes the "B" string to have a slightly higher output relative to the other strings.

Using one of these Firebird Mini Humbuckers, you will notice that the "B" string sounds more compared to the other strings. This small steel plate is part of the vintage technical specifications that contribute to the vintage sound of these pickups.

[charrich56]

"Old School" could mean a wound G back when the G-string really meant something.

...

[loathsome pun alert!]

...Bach's hair in a G-string.

Anybody who would get that reference would also probably know what Salvarsan is, Salvarsan.

But you are probably right about the wound G-string. That means full speed ahead on leaving the darn piece of metal out.

Big_teee has an interesting idea on a hybrid. But I'm a bit cautious about how high the inductance would go with both rails and an Alnico mag. I'd like to stay at or a little under 4.0 Henries series coil, 1 Henry parallel coil, for my specially challenged electronics. I might be able to work with Sonny Walton, who lives close to me (and has a CNC winder,) to experiment a bit.

PRS has been putting out some pickups in their guitars which have an "in-between" string aperture, and I've been hearing some good opinions on some of the minihum and Firebird -inspired custom PU's out there.


-Charlie

[salvarsan]

I wouldn't doubt the "old-school" guys at Gibson tested the pickup with "old-school" strings....

"Old School" could mean a wound G back when the G-string really meant something.

Makes you wonder about how much the G-string actually contributed to the sound of honky-tonk Rock&Roll.
It suggests that limiting the G-string contribution was a priggish cultural affectation, an insidious Bowdlerization of guitar pickup sonority.

G-string issues have a long history.

[trivial pun alert]

Going for Baroque, there is a record of J.S.Bach
contributing a long clipping of his hair to make a multifilar G-string for the violin,
this being the earliest recorded instance of...

[loathsome pun alert!]

...Bach's hair in a G-string.