Tech 21 PE60 Power Engine Tweeter Mod

With the rise of so many amp modeling gadgets in the past decade or so, the need to accurately translate digitized tones in a live setting has become very crucial. Spending hours twiddling knobs, sifting through menus and tweaking tones can be frustrating when the sounds fall flat when paired with a traditional guitar amp. A few manufacturers have responded to these sonic needs by way of FRFR (Full Range Flat Response) amplification options. The Tech 21 Power Engine is one of these options. While it might not technically considered a true FRFR amp, it’s an affordable, solid, lightweight piece of gear that does a fantastic job of bringing amp modeling and digital effect patches to life onstage. As good as it sounds in its stock form, I always felt the addition of a tweeter would nudge the Power Engine more into true FRFR territory and bring out more of the high end sparkle of my Zoom G3 and Line 6 M13. Please note that Tech 21 did offer a tweeter-equipped PE60T (in addition to a retrofit tweeter kit), but they are hard-to-find and from all accounts have both been discontinued as of this writing.

What you’ll need: A Pyle Driver PDBT28 Titanium Tweeter ($10 USD through Amazon), a Power Drill, a 2 3/4 (70mm) Hole Saw Bit ($14 USD from Home Depot), a Small Key Hole Saw, Phillips Screwdriver, Wood Chisel, Speaker Wire, Speaker Connectors (Female Slides), Soldering Gun and Solder.

First step is to remove the actually amp section of the Power Engine. You’ll need to unscrew the four screws that are located on top of the amp.

With the top screws removed, you can remove the four screws holding the amp chassis to the inner sides of the cabinet. You’ll find two screws on the lower right side of the amp chassis and another two on the lower left side. Hold the amp in place as you removed these  screws. Hang onto the plastic isolation tabs that are used to reduced vibration.

 

With the amp chassis out of the way, we can now pop out the speaker grille cloth. The grille cloth frame – at least on my amp – was wedged in fairly tight. You’ll find a small hole on the lower inner part of the cabinet where you can poke a small screwdriver through in order to push the grille cloth frame away from the outside of actual cabinet – pretty clever.

The grille cloth frame can now be gently pulled from recessed part of the cabinet with your fingers.

Next step is to decide on the placement of the tweeter. Once you’ve done that, it’s time to drill out a small pilot hole to make way for the 2 3/4 hole saw blade. A pilot hole will minimize tugging and drifting once you start the actual hole saw cut. Take your time and let the hole saw do the work rather than using your muscle to force it. By doing that, you’ll end up with a cleaner cut and less wood shredding as the saw makes it’s way through the backside of the cut. Now is a good to pencil in the guides for your speaker tabs cutouts as well. A bit of light sanding around the edge of the hole can be done at this time too. 

Using your key hole saw, notch out the cuts extending away from the tweeter hole and then bust out your chisel to remove the remaining sections of wood.

Here’s the final hole and connector notches all ready for the tweeter to be installed.

 Dry fit your tweeter and decide on your screw placement. I went with an offset diamond-looking placement.

Mark your screw holes and drill the tweeter screws in. Here a shot of the tweeter installed. The capacitor wired to the tweeter serves as a 2k crossover for filtering out the low frequencies. There are adjustable crossover solutions but I decided to keep it simple. Plus, 2k seems like a sensible frequency cutoff for guitar.

Next step is creating your Tweeter speaker wires. Grab your speaker wire (I used 14 Gauge wire from an Auto Parts store), your slide-on speaker connectors, a soldering gun and some solder. Measure out the wire, strip the ends, solder up your connectors. One wire will attached to the crossover capacitor. We are wiring the tweeter in parallel with the stock PE60 Celestion 80 speaker. The extra two male slide-on connectors on the stock Celestion make for an easy – and no-brainer – hook-up. A few zip ties and a stick-on zip tie platform keep the wires looking nice and tidy.  

Reverse the disassembly process and put everything back together.

I run two Power Engines in stereo so I placed my final tweeters on the far right and left side of each amp for wider stereo spread and more complex sound. So, how they sound? Amazing! There is definitely more focus in the upper frequencies with a healthy dose of sparkle and air that wasn’t there before the mod. Well worth the 50 bucks I ended up spending. Here’s a shot with the grille clothes removed.

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