Tuesday, July 30, 2024

Dan Armstrong Series/Parallel Blend Pot Mod | Part 2

Part 1

A Schecter Gets the Mod

An MIJ Schecter S-Style was in the shop recently to have the Dan Armstrong Series/Parallel Blend Pot Mod installed. This particular guitar featured three ceramic single-coils, a CRL five-way selector switch, a treble bleed circuit, three full-sized 500K pots, a generic output jack, and copper foil shielding. 

My instructions were to install the Armstrong mod with Gavitt Wire, retain the treble bleed circuit, and replace the tone cap with a 0.022uf K73-16. And so, after verifying the integrity of the existing electronics, I went to work with my soldering iron, solder sucker, and desoldering braid. Clearing excess solder from pot/switch lug eyelets and the backs of pots proved to be a daunting task indeed. Once desoldering had been taken care of, a casualty was discovered, namely, the treble bleed circuit. I guess the heat was a little too much for the tiny ceramic cap to bear.



Damaged Treble Bleed Capacitor



Installing the Armstrong Mod had its fair share of challenges, especially when it came to cramming more than one component into a lug eyelet, and soldering them in place. Another issue concerned the negative leads of both the neck and bridge pickups, which were way too short to reach the blend pot. The only solution was to splice both leads to a length of wire, solder them together, insulate the joint with heat shrink tubing, and solder the free end to lug L2 of the blend pot. After the mod was fully installed, the final step was wiring in a new treble bleed circuit between the input and output lugs of the volume pot. 



Wiring Diagram

Rewired Output Jack

New Trem Claw Ground

Rewired Five-Way Switch

Spliced Neck and Bridge Negative Leads

Tone Pot, K73-16 Cap, Blend Pot

Volume Pot and Bridge Pickup

New Treble Bleed Circuit



I'm pleased to say that the installed Dan Armstrong Series/Parallel Blend Pot Mod worked as it should on this MIJ Schecter S-Style. With the blend knob turned down, the five-way switch operated in the usual manner. However, when the blend knob was maxed, these were the results:

  • Position 1: Neck/Middle Pickups in Series
  • Position 2: Middle/Bridge Pickups in Parallel/Out of Phase
  • Position 3: Middle Pickup Only
  • Position 4: Neck/Middle Pickups in Parallel/Out of Phase
  • Position 5: Middle/Bridge Pickups in Series

Monday, July 29, 2024

Dan Armstrong Series/Parallel Blend Pot Mod | Part 1

Part 2

Dan Armstrong - A More Versatile Strat

Dan Armstrong's 'A More Versatile Strat' was featured in the February 1987 issue of Guitar Player. In the article, Armstrong describes a wiring modification that uses "only the stock parts" of an S-style and retains "all five stock pickup combinations." This mod alters the stock control layout from Volume/Tone/Tone to Volume/Tone/Fader. The fader control [formerly Tone 2] blends in four new pickup combinations, with the pickups either in series/in phase or parallel/out of phase. All this is clearly explained in the scanned article and wiring diagram [Fig. 1] below, as sourced from AshBass.



A More Versatile Strat. Guitar Player Feb 87, p. 96.

Fig. 1: Wiring Diagram. Guitar Player Feb 87, p. 99.



Breja ToneWorks - Dan Armstrong Series/Parallel Blend Pot Mod  

Breja ToneWorks has also posted a very informative YouTube Video on the 'Dan Armstrong Series/Parallel Blend Pot Mod.' By closely following the procedures outlined by Breja, I reckon anyone with decent soldering skills should be able carry out this mod successfully. Be informed, though, that in contrast to Armstrong's wiring scheme [Fig. 1], Breja ToneWorks has swapped the fader pot's hot [input] and ground tabs [Figs. 7, 14].

Stock Components

The images you will see hereon have been adapted from the aforementioned video. Let us begin by looking at Fig. 2 below, in which stock components have clearly been retained. These include the three single-coil pickups, volume and tone pots, five-way switch, and output jack. 



Fig. 2: Components.



Pot Lugs and Grounding

Before we go any further, I'd like to draw your attention to the lugs on all three pots, which have been labeled L1, L2 and L3 [Fig. 3]. Note that L3 is grounded to the casing on both the volume and blend pots. Following this, we will need to solder ground wires connecting the casings of all three pots, as well as a separate ground wire from the back of the volume pot to the tremolo claw [Fig. 4].



Fig. 3: Pot Lug Identifiers.

Fig. 4: Grounding.



Switch Lugs and Jumpers

Having installed the ground wires, we move on to the five-way switch, which may be a CRL, an Oak Grigsby; or a similarly constructed component. For ease of reference, the lugs on the left side have been labeled A1 to A4, and on the right; B1 to B4 [Fig. 5]. The next step is soldering two jumpers. The first [yellow] connects A1 and B4, while the second [blue] connects A3 and B2 [Fig. 6].



Fig. 5: Switch Lug Identifiers.

Fig. 6: Switch Jumpers and Related Lugs.



Switch to Pot Wiring

Now that the switch jumpers are in place, we may proceed to connect the switch lugs to their corresponding lugs on the volume and blend pots. Three lengths of unshielded wire, soldered on each end to a lug, are used for this purpose. The first connects A2 to blend pot L1, the second, A4 to volume pot L1; while the third grounds B3 to the back of the volume pot [Fig. 7].



Fig. 7: Switch to Pot Wiring.



Master Tone Wiring

Let's shift our attention to the pot in between the volume and blend pots, which is the designated master tone control. In order for it to function as such, one leg of the tone capacitor first needs to be soldered to L3, and the other grounded to the back of the pot [Fig. 8]. Following this, a length of unshielded cable is soldered from tone pot L2 to volume pot L1, completing the tone circuit [Fig. 9].



Fig. 8: Capacitor Wiring.

Fig. 9: Master Tone Wiring.



Pickup Wiring

It's now time to wire in the pickups. Each of the three single-coils has two unshielded leads, one black [negative/ground], and the other in a much lighter color [hot/positive]. Starting with the neck pickup, the ground lead is soldered to L2 on the blend pot, and the hot to A3 on the switch [Fig 10]. Meanwhile, the hot lead of the middle pickup is soldered to A2 on the switch, and the ground to the back of the volume pot [Fig. 11]. Finally, the ground lead of the bridge pickup is soldered to L2 on the blend pot, and the hot to A1 on the switch [Fig. 12].



Fig. 10: Neck Pickup Wiring.

Fig. 11: Middle Pickup Wiring.

Fig. 12: Bridge Pickup Wiring.



Output Jack Wiring

Last but not least, the output jack needs to be soldered to the volume pot. In keeping with convention, light-colored unshielded wire is hot [positive], and connects L2 on the volume pot to the positive [+] tab of the output jack. In contrast, black wire is normally used for the ground [negative] connection. One end is soldered to the negative [-] tab of the output jack, and the other is grounded to the back of the volume pot [Fig. 13]. And that's all there is to it, folks! Fig. 14 is Breja ToneWorks' visualization of the completed 'Dan Armstrong Series/Parallel Blend Pot Mod.'



Fig. 13: Output Jack Wiring.

Fig. 14: Completed Dan Armstrong [Mod] Wiring.


Friday, July 26, 2024

Techno RD41 Headstock Repair | Part 1

Related Posts
Part 1 | Part 2 | Part 3

'Techno Guitar RD41EQ3T' is what's printed on the soundhole label of this two-month-old acoustic guitar. Armed with said information, I spent the better part of a hour at the Techno website, only to discover that it wasn't even listed. OK, that's enough griping, methinks.



Soundhole Label

 

The guitar recently suffered a bad fall, resulting in its headstock snapping right off. Luckily, the break was clean, with no missing shards. During a dry run, I was able to mate the headstock and neck after careful realignment, followed by a gentle hammer tap or two. So, then, here are pics of the break and the first Titebond glue-up. The spring clamps are there to provide a little pressure while the glue cures.



Headless Neck

Here's the Headstock

Initial Titebond Glue-Up



Now, since you're already here, let's look at the rest of the guitar. We'll begin with the body, specifically, the softwood top. There's no pickguard, and binding is five-ply black/white/black plastic. Particularly attractive is the five-ply soundhole rosette, comprising alternate rings of an abalone-like material and a dark-colored wood. Rounding off the top is a dyed hardwood bridge. The two pearloid dots on either side of the bridge pins most probably conceal bridge mounting bolts.



Softwood Top

Close-Up of the Top

Five-Ply Binding

Five-Ply Soundhole Rosette

Dyed Hardwood Bridge



The hardwood back of this RD41 features rather attractive '3D' striping and single-ply black plastic binding. The sides, meanwhile, are of the same wood as the back, and bound in three-ply black/white/black plastic. The left side of the upper bout houses a Techno T-170 onboard preamp. Among the highlights of this preamp are three bands of EQ, a phase switch, and a tuner. 



Hardwood Back

Close-Up of the Back

Single-Ply Binding

Hardwood Sides

Close-Up of Right Side

T-170 Three-Band Preamp

9V Battery Compartment/Output Jack

Rear End Strap Button



Moving on to the neck, what you see is straight-grained hardwood lacking any figuring or flaming. The neck heel, however, is far from plain, as it's decorated with a black plastic heel cap. Last but not least is a dyed hardwood fretboard featuring 20 frets, pearloid fret markers, and white side dots.



Hardwood Neck

Neck Heel/Heel Cap

Dyed Hardwood Fretboard

Pearloid Fretboard Dots

White Side Dots


Wednesday, July 24, 2024

July 26-28 | Pesta Kampung Nelayan Batu Hitam

Date: July 26-28, 2024
Venue: Pantai Batu Hitam, Kuantan

Performers:
Art Busker - July 26
Usop Kopratasa and Boey Buskers - July 27
Akustika Abdul and Black Ghostbusker - July 28

Daily Activities for Kids:
Serkap Ayam and Tarik Upih



Pesta Kampung Nelayan July 26-28

July 26 - Art Busker

July 27 - Usop Kopratasa/Boey Buskers

July 28 - Akustika Abdul/Black Ghostbusker

Pesta Kampung Nelayan - Serkap Ayam

Pesta Kampung Nelayan - Tarik Upih