Dig into the weird wiring of the Hofner Beatle Bass and 172 guitar.
Hello and welcome back to Mod Garage! In this column, we will have a look at the famous HA2B control-panel wiring from the German Höfner company (often written as “Hofner” without the German umlaut). The control plate became famous on the Höfner violin bass—the model 500/1 that was released in 1956 and is often referred to as the “Beatle Bass” because of Paul McCartney.
Höfner also used this wiring on a lot of their early solidbody electric guitars, like the famous model 172. These models were covered in colorful vinyl rather than receiving a paint job. The demand for electric guitars was very high in the ’60s, and a paint job was very time-consuming and expensive, so this method was a welcome alternative to cut costs and save time. The vinyl is still an eye-catcher today.
My first real electric guitar was such a Höfner, a later model without the control plate, but still covered in gorgeous red vinyl. Eventually, I removed the vinyl and put some dilettantish paint job on it. When I think about it today, I feel like a lemon.
Frank Meyers recently wrote a cool column about the Höfner company and its history, which appeared in PG’s March 2023 issue, so if you want to find out more about them, please check it out.
So, let’s have a look at the control plate and its very special wiring. It might be considered weird from today’s perspective, but at the time, this wiring was state of the art. The control plate itself and the fancy “tea cup” knobs are still available today—it is called HA2B with an additional letter indicating the color of the plastic control plate, e.g. B (black), C (cream), T (tortoise), and so on.
Photo 2
Photo courtesy of L’instrumenterie, Baptiste Zermati, Villeurbanne, France (https://linstrumenterie.com)
This wiring is designed for a guitar with two pickups and sports an individual on/off switch and volume control for each, plus a rhythm/solo switch, resulting in a total of two pots and three switches. Please note that the plate is labeled in English and not in German, which clearly shows that Höfner was targeting the international market while still selling large quantities inside Germany.
Here is a short summary of what the individual controls are doing, using Photo 2 as our reference:
• neck pickup volume pot
• solo = full output signal / rhythm = output attenuated to about 70 percent
• bass off = bridge pickup on / bass on = bridge pickup off + treble filter
• treble off = neck pickup on / treble on = neck pickup off + bass filter
• bridge pickup volume pot
The way the bass and treble switches are wired up is the real weird part. Back in the day, a neck pickup was often referred to as the bass pickup and the bridge pickup the treble pickup. In this case, the bass switch is for the treble pickup and vice versa. So when the bass switch is off, the bridge pickup is on; when it’s on, the bridge pickup is off. And when the treble switch is off, the neck pickup is on; when it’s on, the neck pickup is off.
This results in the following: When both switches are in the off position, both pickups are engaged (in parallel), and when both switches are in the on position, both pickups are disabled, which works like a kill switch to mute the whole guitar.
This is, for sure, one of the fanciest guitar wirings ever. But believe me, compared to some wirings that were used in the electric guitars of the Musima company in the former GDR, this one here is as harmless as can be.
"There is no law against experimenting with the values of the caps and resistors to tweak the tone to your personal preferences."
Let’s have a look what’s under the hood:
2 x 250k audio pots
3 x DPDT slide switches
1 x 270k + 1 x 100k resistors for the solo/rhythm switch
1 x 0.01 uF treble cap
1 x 0.1 uF bass cap + 1 x 8.2k resistor
You can use any cap and resistor you want. I like to use small film caps and 1/4-watt metal film resistors. It’s nice working with these parts because they are small enough to fit the control plate.
The wiring works as follows:
Solo/rhythm switch: While the solo position has full signal output, the rhythm position engages two resistors to reduce the output to approximately 70 percent by bleeding some signal to ground.
Bass switch: In the on position, the bass capacitor and the resistor filters some highs off to ground.
Treble switch: In the on position, the treble capacitor filters some bass off to ground.
So, here we go for the wiring:
Fig. 1
Illustration courtesy of SINGLECOIL (www.singlecoil.com)
This is the real deal circuit that Höfner used in the early ’60s. The modern overhauled wiring of the HA2B circuit looks very similar, but uses a 0.1 uF treble cap and has no additional resistor in-line with the bass cap. To my ears, the vintage version sounds better, but this is a matter of taste and there is no law against experimenting with the values of the caps and resistors to tweak the tone to your personal preferences.
I would like to thank Baptiste Zermati from the L’instrumenterie company in France for the photos of the vintage Höfner 172—a big shoutout to him.
That’s it! Next month, we will talk about the brand new PRS “Dead Spec” Silver Sky wiring for John Mayer and how you can adopt this for your own Stratocaster, so stay tuned!
Until then ... keep on modding!
This guitar wiring is special in that the two tone controls are freely assigned, and the tone control is bypassed in the two in-between positions. Let’s go under the hood.
Hello and welcome back to Mod Garage. This month, we’ll have a look at the Scott Henderson Strat-style wiring and what it means to bypass the tone control for certain pickup-switching positions.
Bypassing the tone control in a guitar circuit has become popular in recent years, so let’s explore how to do it. We’ve discussed this before in the context of using no-load pots for the tone control. A no-load pot will be electrically out of the circuit when it’s fully opened, so the pot is no longer part of the wiring, and will add no load to the circuit. This way you will have no high-end dampening and the tone is a tad louder, which can be a good thing or not, depending on your personal preferences.
This works great but requires that you open the tone pot(s) if you want this very direct sound. Some players like to have a kind of preset without tone control so there is no additional action they have to take. So, the basic idea of bypassing the tone controls is to transfer it to the pickup-selector switch rather than using no-load pots. There’s no law against combining this mod with no-load pots for the tone control, so you still have the opportunity to use it for sounds where the tone control is engaged.
The credits for this wiring are given to John Suhr, but it’s unknown if he came up with this special wiring during his time as a Senior Master Builder in the Fender Custom Shop, or later, after he started his own business in 1997.
The preset idea is not a new one. Fender has used it since the early ’50s, and the basic idea behind it is still the same. Imagine the following scenario: You’re playing the bridge pickup on your guitar with the corresponding tone pot set to 7 to add some warmth to your tone. In the middle of a song, you need to switch to another pickup that is connected to the same tone pot, but you need the tone pot fully opened to cut through the mix with this pickup setting. Two steps are required now: You need to switch to the desired pickup position, and you need to open the tone pot. Wouldn’t it be nice to have this happen by only dialing in the other pickup position? This is exactly the idea behind bypassing the tone control.
To illustrate, I chose the personal S-style wiring of the award-winning fusion, jazz, and blues guitarist Scott Henderson. The credits for this wiring are given to John Suhr, but it’s unknown if he came up with this special wiring during his time as a senior master builder in the Fender Custom Shop, or later, after he started his own business in 1997.
Henderson is best known for his solo work but also for his band Tribal Tech, as well as for playing with Chick Corea and the Zawinul Syndicate. Henderson released his first solo album, Dog Party, in 1994 and has six solo albums to date. He’s also a teacher at the Guitar Institute of Technology, now known as the Musicians Institute in Hollywood, California. His signature S-style guitar is built by the Suhr company. Henderson and John Suhr got to know each other while Suhr was still working at the Fender Custom Shop, and Henderson became one of the first endorsers for Suhr Guitars.
Henderson wanted an exclusive tone control for the bridge pickup and full clarity in the two in-between pickup positions, so this wiring is exactly what he was looking for.
Henderson’s personal wiring is basically a standard Stratocaster wiring you all know:
- bridge pickup alone
- bridge and middle pickup together in parallel
- middle pickup alone
- middle and neck pickup together in parallel
- neck pickup alone
What makes this wiring special is that the two tone controls are freely assigned, and the tone control is bypassed in the two in-between positions. So, the switching matrix for the Henderson wiring goes like this:
- bridge pickup alone with tone control #1
- bridge and middle pickup together in parallel with no tone control
- middle pickup alone with tone control #2
- middle and neck pickup together in parallel with no tone control
- neck pickup alone with tone control #2
Henderson wanted an exclusive tone control for the bridge pickup and full clarity in the two in-between pickup positions, so this wiring is exactly what he was looking for. Another benefit is that the bypass of the tone controls for the in-between positions is slightly compensating for the little volume loss, which is the nature of the (passive) beast when you combine two pickups in parallel.
In a Strat with two tone controls, changing the standard 5-way pickup selector switch for a 5-way super-switch is mandatory because you can’t do all this with only two switching stages. We don’t need all four switching stages of the 5-way super-switch, so one stage will stay unconnected.
Technically, these are 4P5T wafer switches, and they’re available as open frame as well as PCB-based versions. These switches are physically a lot larger than the standard ones, so depending on what guitar you have, you can run into massive problems to make them fit without rerouting your electronic compartment. Always check this before you buy such a switch to avoid any unpleasant surprises. To make the open version from Fender fit, you need at least 21 mm of space for the switch, but it’s better to have 25 mm to avoid any problems with the soldering terminals.
So here it is, the Henderson wiring as seen in Fig. 1. This wiring uses three 250k pots, a 0.047 µF tone cap, and no treble-bleed network on the volume pot.
That’s it for now. Next month, we’ll continue the tone-pot-bypass journey by looking at a Telecaster wiring, so stay tuned.
Until then ... keep on modding!Let’s go under the hood of these legendary rockabilly machines and explore different ways to enhance a passive guitar system.
Welcome back to Mod Garage. Before we start, some good news! After finishing the relic’ing series, I was able to raise $650 from our Harley Benton guinea-pig guitar in an auction. The money went to our local animal shelter for cats and dogs, to help pay some vet bills.
This month, we’ll take a closer look at the typical wiring you can find in almost every Gretsch guitar. Since 2002, the Gretsch guitar company has been a division of Fender Musical Instruments Corp. But the company has a long history. It all started in 1883 in Brooklyn, New York, when a German immigrant from the town of Mannheim named Friedrich Gretsch started his own shop to make banjos and drums. Sadly, Gretsch died in 1895 at the untimely age of 39 during a visit in Hamburg, Germany. His 15-year-old son Fred (the Americanized version of “Friedrich”) had to run the company. In the 1930s, Gretsch started making guitars and the company had their first heyday. Like many companies during WWII, Gretsch had to stop production of instruments to help in the armament industry. After the war, the two sons of Fred Gretsch (Fred Jr. and William) took their father’s place and started making instruments again. In 1948, the Gretsch Broadkaster drum set was their best-selling item, and the start of another story with a certain Leo Fender offering an electric guitar with the same name, only spelled slightly different.
With the emergence of rockabilly and rock ’n’ roll in the ’50s, Gretsch guitars became popular in the hands of players like Chet Atkins, Eddie Cochran, Cliff Gallup, Duane Eddy, and even Elvis Presley. Later in the game, George Harrison, Brian Setzer, Malcolm Young, and many more became popular Gretsch players.
Sidenote: In 1999, Gretsch took over the Bigsby company, which was their exclusive hardware supplier since 1951. Instruments featuring a Bigsby tailpiece, like the White Falcon, Country Gentleman, Nashville, Duo Jet, etc. are real guitar icons today.
The wiring concept of Gretsch guitars is unique and noticeably different from that of most other companies, offering a volume control for each pickup along with a master volume control. This wiring is combined with a pickup-selector switch and a tone control in basically three versions:
“The interesting part is the arrangement of the volume controls—it’s been said that this was a suggestion from Chet Atkins.”
1. Master tone control (with or without no-load pot)
This is what we know from a lot of other guitars sporting a master tone control for all pickups: Sometimes a no-load pot is used to get rid of the pot’s load when it’s fully opened. Gretsch typically uses 500k audio pots and .022 µF tone caps.
2. Two-way tone switch
There is no tone pot, but there’s a switch that activates two different tone caps as a kind of pre-set tone. Gretsch typically uses 500k audio pots, as well as a .012 μF and .0039 μF (3900 pF) tone cap on the tone switch.
3. No tone control at all
It is what it says: There is no tone control at all with 500k audio pots for the volume controls.
Use whatever tone cap you like best. The 500k choice for the tone pot is a good working solution in a passive guitar circuit. On my own Gretsch 6120, I decided to use 3300 pF and 6800 pF caps on the tone switch, and it works fine for me.
The interesting part is the arrangement of the volume controls—it’s been said that this was a suggestion from Chet Atkins. Having a volume control for each pickup is common on other guitars, like on a typical Les Paul. But the combination with a master volume control is rare … and the source of some unwanted effects. Let’s have a look at the typical Gretsch volume wiring scheme (Fig. 1). I decided to use the one without tone control because this is the basic wiring and can be found on the 6122 Country Gentleman. The wirings with a tone control are identical regarding the volume controls.
This arrangement in a passive guitar system will result in a loss of tone because of two reasons:
1. The three volume pots will drain a good portion of high-end to ground when rolling back the volume, which is the nature of the passive beast.
2. Long shielded wire runs are used inside the hollowbody Gretsch guitars, adding capacitance to the system, resulting in even more high-end loss.
Even with the pickup height adjusted correctly, the loss in high-end is clearly noticeable, so let’s see what can be done. For some players, this is no problem at all and part of the tone. If you’re happy with the way your guitar sounds, there’s no reason to change the system. If you want a clearer tone with more high-end definition, you have the following options.
If you don’t want to convert your Gretsch guitar into an active system to get rid of the high-end loss, you’ll need to compromise by adding a treble-bleed network to the volume pots. We talked about this sometime ago in detail [“Mod Garage: Deep Diving into Treble-Bleed Networks”].
Selecting the right treble-bleed network is a matter of choice. What works for me might not work for you. Maybe you like some more high-end when rolling back the volume than others or vice versa. With the typical Gretsch Filter’Tron pickups, I like a 470 pF cap with a 150k resistor in parallel. Try this as a starting point and see if you like it. In theory, you’ll need a treble-bleed network on all three volume controls, which gives you a wide control regarding sound. In my own 6120, I use different treble-bleed networks because I want more high end from the neck pickup compared to the bridge pickup. I’ve also seen configurations with a treble-bleed network on the two volume controls for the pickups and without one on the master volume control. Personally, I don’t like this configuration. Using one on the master volume and not on the two controls for the pickups will have a better result.
You see, it’s a wide field of experimentation, but it’s worth the effort. While you’re in there, I recommend changing the 500k audio volume pots for 250k audio pots to benefit from the much better taper in a passive system. The difference in high end is minimal (if audible at all), and you can compensate easily with the treble-bleed network by choosing slightly higher values. I did this in my 6120 and the difference was huge.
“Don’t underestimate the time you’ll need to get the electronics of a hollowbody guitar out and back in. Even on a good and clear day, you can’t do this within 30 minutes, so don’t hurry.”
Don’t underestimate the time you’ll need to get the electronics of a hollowbody guitar out and back in. Even on a good and clear day, you can’t do this within 30 minutes, so don’t hurry. If you’ve ever changed the electronics inside such a guitar, you know what I mean.
Gretsch uses shielded wires inside, but sadly, the quality is only average. The wire has a high capacitance, and, especially inside big hollowbodies, you can find up to 2.5 meters (about 8.2 feet) of it, which is a real sound killer on its own. The shorter the wire, the less capacitance it will add to the circuit, so you should optimize the length of the wire wherever possible. If you want to stick with shielded wire, you should use a high-quality one with a low capacitance. I like to use the .155-diameter George L’s high-end wire for this. It’s very thin, with a capacitance of only 19 pF per foot, which is unbeatable ... but still affordable.
In comparison, I measured 46 pF per foot with the original wire from the factory. The before/after effect will be like lifting a blanket from the amp. But you can also use non-shielded wire if you’re not concerned about shielding. I replaced all wires in my 6120 with the George L’s .155-diameter cable and was able to reduce the original length of the wires to 50 percent, which means reducing additional capacitance to the circuit noticeably.
As you can see, tone is not set in stone, and there are ways to enhance your Gretsch wiring. Next month, we’ll dissect the Scott Henderson Stratocaster wiring, so stay tuned.
As you can see, tone is not set in stone, and there are ways to enhance your Gretsch wiring. Next month, we’ll dissect the Scott Henderson Stratocaster wiring, so stay tuned.
Until then ... keep on modding!