To clear up any confusion - simply choose a safety resistor value that matches your amp's output. I was building a bunch of these when I made the video. That's why you're seeing a bunch of different resistor values. The WEM needed 16 Ohms and a Fender Champ would need 4 Ohms but most amps will need 8 Ohms - Huw
This was helpful! I’m currently trying to configure a way I can add a Main speaker out and also be able to patch in to any combo as a cab only. This points me in the right direction. I’m trying to understand the OHM load. If it’s switched to external and no speaker is plugged in, I understand the dummy load to protect the circuit, great job! My guess is the switched jack disengages the dummy load when plug is inserted? Very nice! I think I’ve got it figured, watched it like 7 times now.
That's correct. The load resistor is only in circuit when there's no external speaker connected. Just a safety measure really. And yes, plugging in the external speaker disengages the resistor
your saying a switching mono jack - but that looks like a stereo jack? Are they called something different in the US - I can't find a "switching mono jack" for sale anywhere and I can't really quite see what the jack is in the video - sure looks like a TRS stero jack? But it seems you wouldn't want a stero jack in this particualr situation because you'd want it to be shorting to not blow the amp
It would be interesting to have a stomp box that could switch one amp head between 2 cabs, I have a Mesa TransAtlantic 15, I would love to be able to switch between cabs on different amp channels. Great video!
Love these projects. Sadly, I cannot wire up a jack plug properly, it seems, let alone follow even a simple schematic. My guitar playing is pretty hopeless too. Happily, I can make a banging seafood Thai red curry, so I get by. Happy Christmas to Huw, Ed, your families and all the good people who watch Tone Twins TV. Keep well, y’all!
Thank you for this. May I ask the specs of the toggle switch you used? It appears to be of higher current carrying capacity than would be found in normal ABY box.
Nice little project, however I'd recommend using star washers on the jacks to insure a proper ground connection if you decide to not solder together the negative connections
That's so much better than what I've done to my old Gibson amps! I just used an L clamp with a hole drilled through to fit a mono jack and mount it to the inside of the cab. In the future I will make this switch box instead. Thanks!
Simply choose a safety resistor that matches your amp's output. I was building a bunch of these when I made the video. That's why you're seeing a bunch of different resistor values.
Another great project. I really wanted to build the attenuator you made the guide for but I've really struggled finding a 16 ohm Lpad as I want to use it with my Ac15. Any suggestion on the best websites to try or are they simply not available?
A lovely project & video. You could use a switching jack to do the job of the toggle switch and not need the safety resistor. The jack is “normalled” to connect the amp to the internal speaker(s) and when you plug in a jack to external cab it breaks the connection to the internal speaker.
It's a good suggestion Al. The idea here, however, is to be able to switch back and forth instantaneously rather than plug and unplug. Just a bit quicker and easier in a recording situation.
I was wondering the same thing but makes sense for the quick switching scenario. The only thing to be carful of I suppose is that the cab end of the speaker cable is always plugged in or you could still be running the amp with no safety load and a disconnected speaker
