Tuna Footswitch

I bought my SVT2 Pro from my friend Janis sometime in the late nineties for about $800. I really had no idea what it was, just that it said Ampeg like all the other bass players had and that it was very, very heavy. It must be good, because it weighs a lot, and was dubbed by Incantation as “the fucking brick” on Impaled’s tour with them in 2000. It had been on tour with Janis while she played in Stone Fox and L7. I guessed it was pretty good, but I was still too busy trying to learn to play and keep up with my bandmates who’d all been playing years longer than I to actually read about my purchase.

After a love / hate relationship with constant amp breakdowns for a decade, I finally figured out the SVT2 Pro had a vent on the side. I also figured out Ohms, and that I’d been abusing this poor thing for years with incorrect speaker hook ups. Sometimes, realizing my stupidity overwhelms me.

As I found out years later when I stopped to pay attention to such things, this is a great tube amp. It’s basically an SVT Classic with some bells and whistles attached. SVT, the pinnacle and the last great leap in tube bass amps. Now, about a couple of those bells and whistles…

One thing I’d never taken advantage of was the tuner out. As I got to know more about true bypass, I realized I didn’t have to think about it if I used the tuner out. One less pedal in my signal chain. But what about silent tuning? Well, the SVT2 Pro also has a footswitch input allowing you to mute and / or engage the graphic EQ for a boost.

So, a little more than a year ago, I picked up an Ampeg AFP2 off eBay. This is a dual footswitch that works for my SVT2 Pro. It’s really a simple device, just two DPDT footswitches that connect and disconnect ground to engage the mute or graphic EQ, along with indicator LEDs.

It works with a single TRS cable, aka tip-ring-sleeve. That means the cable has three conducting wires inside, two for signal and one to ground that is shared by both switches in the circuit. It’s an elegant way to work two functions in the amp with a single cable.

Side note: there is an AFP2-B that is exactly the same but has the correct labels for the switches. My OCD states I must keep a search open on eBay until I get one if these, though I have something that does the same job equally well. But it doesn’t say “mute” and “EQ” and this haunts my soul and I lose sleep at night. What. The. Fuck. Someone find me one of these.

The AFP2 came with a 15′ TRS cable. That’s way too short for where I stand on some of the stages I play, and therefore rather pointless. I started looking for a replacement, but all I could find were cables by Hosa that were all shielded and bulky and stupid and kinda pricey, as TRS cables are usually used for video and sound. My use was just for a footswitch, where signal noise wasn’t such a concern, and I wanted a cable thin and easy to pack like the one it came with. Time to cobble one together.

I went to ye Olde Timey Electronics store (Al Lasher’s in Berkeley) and asked for the thinnest three-conductor cable they had and some TRS plugs. It was then I realized I could also use a thinner cable for the tuner out as well, since I wasn’t worried about signal quality. It wasn’t going to make any sounds, just tune. What if I bound them together? That would make setting up live easier. Even easier if it was color coded, so i could tell the difference easily.

Sa-weet. I bound the two wires together with tape, though I could’ve invested in a long piece of heat shrink (this is about cheap, workable solutions, not necessarily elegant). Now I could plug in the tuner and footswitch and keep ’em nearby on my pedal board with only one cable.

I ended up using this set up for some time on a few tours and I really liked it. With the tuner always on, I could check my tuning as I was playing a song. The graphic EQ boost was used a few times to fill up some room during bass breaks. The mute was solid and killed any buzzing from distortion pedals or anything else that was previously in the chain after the tuner. The thin, DIY dual wires packed up nicely and didn’t take much room in my homemade pedal case.

Wiring up some 25′ cables to some standard 1/4″ and a 1/4″ TRS plugs is not hard. This isn’t about teaching how to do something so simple, it’s about stopping to realize what you already have on hand and milking the most out of it.

Doktor Ross Sewage
The G.O.R.E. Corps Minister of Filth

One thought on “Tuna Footswitch

Leave a Reply

Your email address will not be published. Required fields are marked *