Changing the pickup in an Acoustasonic Player Tele

 Why change the magnetic pickup in the first place?

As I played my Acoustasonic Player Tele, I noticed that the magnetic pickup was generally weaker (especially the B & E strings) and had a lower overall volume than the piezo. It was also quite noisy, even though this was supposedly a noiseless N4 pickup. Switching from an acoustic tone to an electric tone became problematic, since, in my opinion, the whole point of using the electric tone was to play lead lines - a volume drop-off was unacceptable.

To verify that my ears were correct, I measured the magnitude of the volume drop, and on average, it was about 6dB lower on the magnetic pickup, which is half the voltage. 

Based on this information, I felt that a pickup swap was in order.

A little background on my guitar

I had been considering acquiring an Acoustasonic for a while, but the price was off-putting. The American versions were selling at the time for $2000, and the MIMs were at maybe $1200, and I was not willing to spend that much. In addition, online research indicated several design- or QC-related problems (reliability, electronics failures, battery issues, etc.), and I became even more hesitant. Wile perusing Reverb one day, I found that Franklin Guitar Works was selling a number of refurbished Player Teles at a price of only $499. As I recall, you could get any color as long as it was butterscotch, but I jumped at the chance anyway.

My guitar arrived with the factory gigbag (one of the best I have ever seen and second only to my Mono Vertigo gig bag in quality), and it played well. After a quick tweak of the truss rod and the Micro-tilt, the guitar played beautifully. Over time, I began to identify several design flaws and took steps to correct them, so I was glad to have spent relatively little for the guitar. Had I paid full retail, I would have been quite angry.

Investigating the N4 pickup

I removed the N4 pickup and took the cover off. In the photos below, it can be seen that the N4 is a stacked pickup, which is one way to design a humbucking single-coil-sized pickup. The result is a very tall pickup when compared to standard single-coil designs. It is also interesting that the B and E polepieces seem to be missing. In fact, they are much smaller than the other polepieces, and this was likely done in an attempt to balance the signal between the plain B&E strings and the bronze-wound acoustic G, D, A, and low E strings. This seems logical at first, but in practice, it did not work effectively.

 

Which pickup to choose for the replacement?

For this application, I decided that a humbucking pickup was the best idea, especially since one of the main concerns was noise with the stock pickup. It turns out that I had on hand a GFS Lil' Killer, which is a twin-blade humbucker, with a resistance of 10k (GFS offers two other versions, a 7k and 15k). I have used GFS pickups in several guitars and found that they sound really good and are very economical. I have an older MIM Tele that I installed a GFS Lil Puncher, which is the Tele bridge equivalent of the Lil Killer, and I quite like the way it sounds. Twin-blade pickups in general offer better string-to-string balance, especially with bending, since there are no gaps between the polepieces where the magnetic field strength can fall off.

Installing the replacement pickup

The N4 pickup is mounted under the top of the guitar via two standoffs that are swaged into the wood top, so the mounting screws are inside the guitar, rather than accessible on the top, like a typical Tele or Strat. This leads to another problem that many owners have had - the two screws tend to work themselves loose over time, resulting in mechanical buzzing of the pickup against the top of the guitar.

These standoffs do not really allow for pickup height to be adjusted upward, and the length of them was chosen specifically because the N4 is very tall. In the photo below, the GFS pickup is on the left, and the N4 is on the right (I had made an attempt to reduce the noise by applying copper shielding tape to the plastic cover of the N4 and connecting ot to ground. This helped, but did not entirely quiet the pickup). 

Not only is the N4 taller than a standard single coil (the GFS pup dimensions are typical of a standard single coil pickup), but the mounting holes are very slightly further apart than a standard pickup. Luckily, the GFS is wound on a fiber bobbin, so modifying the hole spacing would be easy to do, since the N4 is tall, and the GFS is normal height, the result would be that the GFS would be further away from the strings, resulting in lower overall volume, so that was not acceptable.

I decided to modify the fiber bobbins further to create a semi-circular notch on each end, allowing the GFS to be mounted flush to the underside of the top of the guitar, thus ensuring the dual rail poles are closer to the strings. In the photo below, the notch is clearly visible.

This created an additional issue of how to secure the pickup in the guitar. I happen to own a 3D printer, so I designed small L-brackets that would clamp down on the pickup to hold it in place. I did not investigate any other methods of creating these small brackets, but I am sure that with the proper tools they could be fabricated out of wood. 

These L-brackets are held down by the original mounting screws, and to this date (two years later) have remained secure.

It is possible that had I used the "hotter" 15k ohm version of this pup instead of the 10k, the height difference and resulting volume loss would not have been a problem, but the 10k works very well in this application, and to my ears, sounds great. Note that neither pickup, the N4 or the GFS, made this guitar sound anything like a Tele in the bridge position - keep in mind that both the piezo and magnetic pickups pass through the DSP board and are heavily processed. The magnetic pup seems to have a little more midrange, and there is likely some compression being applied as well, all in the digital domain. Since I have the MIM with the Tele version of this pickup I can say that the raw pickup sounds like a beefy Tele bridge pickup with enough brightness and snap to sound like a Tele, but with a bit more punch like a humbucker. The Acoustasonic does not sound like that at all, but it is a quite usable electric sound that the vast majority of audience members will find believable. 

Wiring

The GFS is a four-wire pickup, new versions use their "Kwikplug" wiring system, but mine was an older model and did not have connectors attached. 

The N4 had two wires, Red and Green, which soldered to the main DSP pcb as shown in the photo below, with Green soldering to the GND connection, and Red (the signal wire) soldering to the MAG IN pad. (The Black wire to the right of the Red wire is the ground connected to the bridge plate)

The GFS has four wires, Green, Red, Black and Shield. According to the instructions, Red and White are tied together, Green is the signal, and Shield goes to ground. 

Conclusion

Swapping the magnetic pickup on the Acoustasonic is not a difficult task, but the design of the guitar does not allow for easy repair or modification (unlike a Telecaster) and therefore requires some unusual steps and considerations. Overall, the tone of this new pickup is better balanced, even with acoustic strings (D'Addario Bronze 10s), and is only slightly louder than the piezo pickup, which works well when switching to an electric lead tone. Noise has been significantly reduced when compared to the N4, so this has been a worthwhile undertaking.