Two dusty old Muffs…

[pricklyrobot]

…well, okay only one finished Muff at the moment. Second coming soon.

I’ve had a GGG Op-Amp Muff kit sitting around forever, and a BYOC NYC Muff kit (guess it’ll be my last BYOC build ) only slightly less long.

Finished the Op-Amp on Saturday. Features a Crested Caracara, pretty common site around Austin and south of here, but very rare to see one outside of TX. Very cool raptor/scavenger. Read all about ‘em!

Crested Caracara Overview, All About Birds, Cornell Lab of Ornithology

The Crested Caracara looks like a hawk with its sharp beak and talons, behaves like a vulture, and is technically a large tropical black-and-white falcon. It is instantly recognizable standing tall on long yellow-orange legs with a sharp black cap set against a white neck and yellow-orange face...

www.allaboutbirds.org

The mods are adding a Tone Bypass switch to the GGG, and making the High a Low-pass cutoff frequencies adjustable on both:


I spent quite a while plugging values into here http://www.muzique.com/schem/filter.htm until I arrived at something that seemed like a useful range. Gave the high-pass a wider range, so it could overlap the low-pass range and get a band-pass response:


Then it was time to figure out what pot tapers would give me a useable sweep:



The verdict
If I was going to do it again, I’d pick a different PCB (sans off-board wiring) and/or use a bigger enclosure, so I wouldn’t have to use 9mm pots and have a spaghetti mess of wiring. But I wanted to use up stuff I already had, and I made it work in the end

Re: mods
The Tone Bypass is definitely noticeable, and useful. The adjustable filters are a little more subtle, I’ll have to play with them some more. Kinda wish I had a stock Muff to do a side-by-side comparison. It was an easy mod though, just swapping two cap values and changing two resistors to pots. Doing the calculations to try and figure out right values for everything was a good learning experience if nothing else!


* I’ll add Muff #2 in this thread, whenever it’s done…

 

[rwl]

Looks great! Are those enclosures etched?

 

[pricklyrobot]

Looks great! Are those enclosures etched?

Thanks! I’ve enjoyed seeing your excellent bird-themed builds as well.

They are etched, yes. I use this method:

Stop Using Ferric Chloride Etchant! (A Better Etching Solution.)

Stop Using Ferric Chloride Etchant! (A Better Etching Solution.): Ferric chloride is a traditional home-use circuit board etchant. It's easy enough to come by, and the Ferric by itself is no big environmental problem. However, once you've etched a board with it, you're left with a solution...

www.instructables.com

 

[Feral Feline]

Like a magpie drawn to a shiny bauble, in swoops RWL...

I love birds of prey, especially falconidae, and I love messed-with-Muffs... So I guess I'm a magpie, too.


LOVE how the knobs on the BLARE echo the Crested Caracara's colouration. Thanks for the link, btw. Wish I'd spotted a Caracara when I visited Corpus Christi/San Antonio years ago.


In addition to being cool builds in general, kudos for using what you've got on hand.


You used Jack Orman's calc (I practically have that page open all the time in my browser); did you also use the TSC MUFF CALC at all?

 

[pricklyrobot]

No, I hadn’t seen that TSC page before. Will definitely bookmark that one, thanks.

Apparently the Caracaras used only be common in south Texas, but they’ve been expanding northward in the last few decades.
The other more falcon-y looking falcons we see most commonly in central TX are Kestrels (very cool bird as well, I’ve got an old Rat build with a Kestrel on it). We see Merlins sometimes, and the occasional Peregrine. We’re in the range for Prairie Falcons but I don’t think I’ve ever definitely ID’d one.
The Aplomado Falcon is the proverbial rare bird, only to be seen in far south coastal TX. I got a very crappy view of one, once

 

[pricklyrobot]

Here’s the Kestrel. Another old BYOC kit!

 

[pricklyrobot]

Finally got round to finishing Muff No. 2 (BYOC NYC Muff). Featuring the Cooper’s Hawk. A bird that mainly hunts other birds. Have them in the backyard here with some regularity.

Cooper's Hawk Overview, All About Birds, Cornell Lab of Ornithology

Among the bird world’s most skillful fliers, Cooper’s Hawks are common woodland hawks that tear through cluttered tree canopies in high speed pursuit of other birds. You’re most likely to see one prowling above a forest edge or field using just a few stiff wingbeats followed by a glide. With...

www.allaboutbirds.org

In the gutshot you can see the 1N4001 that I originally put in backwards
Dumb rookie mistake, that I’ve weirdly never made before. Oh well, at least I spotted it before I posted a troubleshooting thread