dannybuoy

If you route the strap on a Thunderbird over the front of the lower wing, it stays bolt upright. You could even hang your coat on the end and you wouldn’t get any neck dive!

Maybe not if using a Freaker and the volume is shut off when the pedal is in the heel position. The loop could be always on. But in reality you would probably have a bit noise still bleeding through.

I don't know of the Demon would be too big to fit on the G-Lab. Regarding the Freaker, for it to work well it would need to 100% shut off the signal at the heel end (I'm not sure if a tiny bit still comes through), and then to use something like a Boss LS-2 to split and mix 2 parallel chains, chain A being your regular bass and B having the wah+distortion.

Lots of amps have one built in anyway, but it’s not easy to discover which ones. I recall a thread on Talkbass with Agedhorse, a designer of Genz Benz amps talking along the lines that all their amps had such a filter but they never marketed the fact.

Looks like that particular wah already has switchless activation: https://www.morleyproducts.com/2020-power-fuzz-wah/ Switchless Wah activation, simply step on to activate and step off to bypass. Checked out a demo though and it looks like the fuzz was not activated in the same way though and always on when engaged.

V2 has a switch where you can disable the volume drop at the heel end, resulting in a low pitched rumble instead. They make a mini version too. I had the V1 many years ago! A Whammy is another option, totally different effect but on the divebomb setting it can go from a low pitched rattle up to a piercing scream, it’s a lot of fun!

Another option, not cheap or easy to find, but throwing it out there. The Wilson Freaker wah drops the volume right off when back at the heel. Run that with a distortion in a parallel chain and you can just step on it to do your thing. Sounds great on bass, I’m thinking of buying one again!

Ok, a G-Lab true bypass wah pad is a pressure sensitive FX loop... Stick a wah on top of the platform but also a distortion through that loop and Bob's your uncle. Or a Source Audio Manta, Spectrum or C4, or EHX Enigma can be set up as a one-press envelope filter with built in distortion.

A blender will just let you cross-fade between wet and dry... But if you just put a distortion or something in there I'm not convinced you'll find what you're looking for. A wah pedal into or after a distortion/fuzz pedal though... Check 37 seconds in here: (And cheeky plug, I have a Hotone Bass Press in the classifieds that'll do the job admirably!)

Not a serious suggestion above, just fitting in with the theme! What about a wah pedal? That’s the only thing I can think of that could come anywhere close to what you’re describing.

Maybe, but nothing wrong with that! I’d just bang a Spectracomp in front of the Ultra and call it a day!