So after some rig simplifying and downsizing, I went back to the TC Electronics Flashback X4. Tonewise, I couldn't be happier. I just love this thing. It's just easy to play, and even easier to dial in. My only gripe was the lack of external tap tempo - I have my delay on the back row of my board, centered, but I've become accustomed to having a small, dedicated tap-tempo button on the front row. (It's easier for me to tap with my heel down, rather than balance on one foot and tap the back row OVER other pedals.) I did my research on TGP, and found some threads on a modification. I decided to compile this info, and re-post here. Basic Info: Despite the large housing of the pedal, there's not a tone of room to place a jack inside, due to inner components, and aluminum reinforcement "ribs" of the shell. The tap-tempo switch is "Normally Open". It senses the tap by the switch closing, and making contact. (Tons of folks on eBay and Reverb make Tap boxes for +/-$25.00) The internal tap-tempo switch has 4 contacts. The top 2 and bottom 2 are connected. (Checked it with a multimeter) The TC FBX4 uses what appears to be lead-free solder The TCFBX4 uses 6-point star-head screws I highly recommend using a Switchcraft flush-mount jack (see pictures). It's the narrowest 1/4" jack you can find, and fits in perfectly. My other standard sized Neutrik and Switchcraft jacks couldn't fit in the space. NOTE: I've read about connectivity problems with the Rean equivalent jack. I decided to spend the extra $5 bucks and go for the Switchcraft Before you start: Find a 6-point Star screw bit that fits. WELL. If you don't you're in for a bunch of headaches. The screws are zinc, not stainless. Do not over-tighten. Lead-free solder is hard to work with. It's great for PC Boards and wave soldering. Not so much for hand soldering. It melts at a higher temperature than standard lead-based solder. Make sure you have a GOOD iron, 40W, with a very very pointy tip, that's CLEAN, and tinned. The enclosure is aluminum, which is soft, but the walls are thick. If you want a clean hole, please use an Irwin step-bit. Drilling: The best place that I found to place the jack is on the RIGHT hand side, right above the LED for the Tap Tempo. (See pictures) If at all possible, try to rig up a shop-vac so that it sucks up all the aluminum shavings AS they're being drilled. If that's not possible, PLEASE cover all the boards/circuits so that the aluminum chips/dust to not scatter and stick to, or damage, the pedal's components. Use a step bit, steady hand, take it easy Wear Eye protection Soldering: Lay off the coffee and or booze. You'll need a steady hand. Strip off 1/8" of the wire insulation. Use 37/63 Solder if you want any chance of success. Use a piece of tape to hold the wire in place with the contact nib. Don't rely on your hand to hold it. You'll get a cold joint. Make sure the wire doesn't move/jiggle while soldering Use a 40W iron, do it fast and clean, like a surgeon. The traces are VERY close together. If you hold the heat on too long, or slip, chances of damaging something are very, very high. NOTE: I've heard of one person using the existing "expression jack" for this. They de-soldered the expression jack, removed it, jumpered the leftover traces, and re-used the jack for tap tempo. Unless you're a soldering master ninja, I'd advise against this. The chances for failure are significantly higher. If all goes well, your external tap tempo should work flawless, and your internal tap tempo will ALSO continue to work. I hope this thread will help anyone who wants to tackle a seemingly simple, but deceptively delicate task, of modding their Flashback X4 for Tap Tempo. Here's some pictures. Clean hole. Looks un-centered between the nibs, but notice where the LED post and screw post are... I used heat-shrink around my jack just for fun. My soldering micro-blobs are not textbook perfect, but it was very difficult combining the leaded with lead-free solder. They're shiny, and solid, so I'm not f*cking with them! This jack looks super low-profile. I love it. Pancake jack fits in nicely on my tight board. I was lucky enough to score a Mansel Effects Tap Tempo that is 95% the same color blue as the FBX4. Matchy-matchy! Yes!!!! Now, I can easily tap in tempos with my right foot, heel down, and not have to balance on one leg.