This DiMarzio Tone Zone was installed as a bridge pickup in an Ibanez RG652FX, with a DiMarzio Air Norton neck pickup.
DiMarzio Tone Zone half air mod
DiMarzio lists the Tone Zone as having a DCR of 17.31 kOhm, with an output of 375, and Bass/Mid/Treble as 8.5 / 8.5 / 5. I measured the two coils at 9.1 kOhm (Slug coil) and 8.3 kOhm (Screw coil) – a “dual resonance” pickup.
The high output and bottom/mid-heavy equalisation does not work for me. The “Half Air Mod” is reported to open up the sound, reduce output, and remove some bottom heaviness.
The DiMarzio “Airbucker” pickups have a space between the magnet and poles: This supposedly reduces the inductance, and the gap between the slugs/polepiece screws and the bar magnet reduces the magnetic field strength at the strings, the overall result being lower output, with a more open/airy sound and more treble response. DiMarzio also does “Virtual Vintage”, where three short steel slugs are inserted into blind holes in the coil bobbin. This is said to smooth down treble response. These slugs are reported to measure about 8 mm long, 4.2 mm diameter. (Interesting aside: One analyser claimed his measurements on the Red Velvet single coil, fitted with the bottom “power plate”, shows insignificant inductance and frequency response difference with and without the plate.)
The usual Tone Zone “Half Air Mod” involves removing the steel spacer bar from the polepiece screw side, sliding the magnet up against the screws, leaving a gap at the slug side. I have not read about anybody inserting “Virtual Vintage” slugs with this mod. I decided to reduce the bottom diameter of the slugs (like for a normal DiMarzio Airbucker slug), and fit a reduced size steel spacer on the screw side. The magnet thus stays in the original position, with a magnetic connection to the screws (bridge side of the coil – trying to maintain high frequency response).
The difference between this “half aired” Tone Zone and the DiMarzio Air Zone should be that the Air Zone has gaps on both sides of the magnet. The home-brew aired Tone Zone is reported to sound different from the Air Zone. Interesting though, the DiMazio specs for the Air Zone has the same Bass/Mid/Treble values, but with an output of 323.
The polepiece screws on this Tone Zone are not all the same length. The E, A, D screws are longer, with the G screw being the shortest. Magnetic field manipulation? If DiMarzio does it like this, then altering small things within a pickup must have an effect? They do not advertise this screw configuration, so I do not see it as snake oil.
Original slugs and screw coil metal spacer. The polepiece screws do not screw into the metal spacer, the holes in the spacer bar are 3.6 mm diameter, with the 5-40 screws 3.1 mm diameter: The polepiece screws are a bit “aired” anyway. The slug coil bobbin shows the extra holes used for the “Virtual Vintage” slugs.
My modified slugs. Bottoms turned down to 2.9 mm diameter, 4 mm long (4.5 mm for “G” string slug – to allow setting it lower).
New steel spacer, compared to the original spacer. Offset material volume, hoping to lower the G string volume.
Original spacer bar weight 7.34 gram. New spacer weight 3.14 gram.
Original slug set 10.97 gram. Modified slug set 8.96 gram.
As per DiMarzio practice the magnet was spaced from the slugs with three, 3 mm tall pieces of plastic tubing. The gap between the slugs and magnet is about 1 mm, and the space between the polepiece screws and the magnet is also about 1 mm. (I do not have my technical notes on hand, but I might have “normalised” all the pole screw lengths to 12 mm.)
Result? Lower output than standard, lighter sound, useful for light bridge overdrive playing, but no chime, sparkle or life, not inspiring. Better than standard, though. It has a something, but not quite there yet. I suspect even a full air mod will still be too lifeless.
DiMarzio Paf Pro air mod
While I was doing the Tone Zone rehabilitiation, I also obtained a Paf Pro, to replace the dull Air Norton in the neck posistion. The listed output is 300, and, as the then available bridge candidates also ran around 300 – 320, I decided to “Air” the Paf Pro, to reduce output, hoping it will match up with a 300 – 320 output rated bridge pickup.
I have no pictures of the work, but the internals look the same as the screw side of the Tone Zone: Polepiece screws (all equal length, around 15 mm?) with steel spacer plates for both coils. I made up two white “Perspex” spacers, dimensioned as per the steel spacers, with a slightly better fit. This differs from DiMarzio’s way of inserting plastic rings around the two outer and center screws. I also made up “Virtual Vintage” slugs, using M5 screws, about 6 mm long, to screw into the six open holes in the coil bobbins, which I tapped to M5.
I also re-wired the RG652 FX with new CTS 500 kOhm audio taper long shaft pots, Kinman treble bleed (150 kOhm, 0.001 microFarad), and 0.01 microFarad tone capacitor (standard capacitor marked “223K”, 0.022 microFarad?). I really should post a picture of my “earth bus” plates under each pot. No soldering of wires to the potentiometer casings. I worked on the bridge plate bottom, sanding it flat (the casting is bowed), made a bone nut (not a very succesful effort, will have to re-do it later), cut tapers on the bottom of the bridge intonation cap screws’ heads, to allow self-centering in the large holes in the bridge, as well as dressing a fret or two. “Japan, Prestige” Ibanez it might be, but it needed work. Initial tests were done with old strings, before I fitted a new set, to set intonation. Why? The locking tuners had sharp edges where the strings bend out of the holes, causing the plain strings to snap immediately when you tighten them again after putting back the pickups/nut. I tried to smooth those edges, and wrapped more string on the peg.
I have been afforded only a few sessions to play the guitar after these mods. The Paf Pro “LITE” is something. Better sounding than any other pickup I have used to date. I really like the tone characteristics – clear and bright but not harsh/sharp trebly, pleasant mids and lows, smooth, rounded, balanced, some depth to it? I need a bridge pickup with similar character!
The volume match between the half-aired Tone Zone and the aired Paf Pro is almost acceptable, with the Tone Zone being a bit softer, needing to be raisied a bit higher than I would prefer. I do not know if my Tone Zone Half Air modification lowered the output more than I hoped for, or if my modifications to the Paf Pro did not reduce output much. No signal generator to do the before-after measurements. Which still leaves me with the problem of a new bridge pickup choice: I would prefer volume not to change much when switching between the two. I hope to get back to this project in a few months’ time, and shall post more pictures.