Author Topic: 4-Knob Rat (and Lasers)  (Read 1938 times)

323effects

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4-Knob Rat (and Lasers)
« on: January 28, 2019, 10:16:24 AM »
Built a 4-Knob Rat for a friend back in October last year. Loved the way it sounded and had the extra PCBs and parts, so I went ahead and built myself one too. Nothing too fancy here, mostly posting for the laser content  ;) 
Took the gut shot before the 308 came in. Used an NOS metal can for extra mojo. Haven't A/B'd with a DIP 308 but this thing sounds pretty dang smooth (or at least as smooth as a Rat can).



Actually built this back in October with the first Rat, but just made the faceplate over the weekend to finish it off.  Faceplate is 1/16" Maple, using a an el-cheapo 1.5W diode laser (like this one http://www.madbeanpedals.com/forum/index.php?topic=28072.msg272974#msg272974).
Single pass using just under full power at about half speed to get a nice deep burn without charring the rest of the wood. Then a few coats of Tru Oil to tone the maple down a bit.  Sprayed a light coat of clear over that which was promptly sanded back off cause it was just too glossy.  My technique needs some work, but overall I'm happy with the way it turned out. 



Also channeling my inner Pickdropper with that 1590A in the background  8)

jjjimi84

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Re: 4-Knob Rat (and Lasers)
« Reply #1 on: January 28, 2019, 11:25:12 AM »
Nice job, I love the wood faceplate! How are you doing the switching with a spdt, is the relay under the input/output jacks?

323effects

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Re: 4-Knob Rat (and Lasers)
« Reply #2 on: January 28, 2019, 12:14:56 PM »
Thanks jimi! Think i need to take a little off the edges to let some of that seafoam create more of a border on the face though.

Switching is relay/arduino based - and yeah they're under the I/O jacks. Makes troubleshooting a nightmare if anything goes wrong wit that stuff, but man it looks so much cleaner to me this way.

jjjimi84

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Re: 4-Knob Rat (and Lasers)
« Reply #3 on: January 28, 2019, 01:21:49 PM »
I think taking a little off is a great idea, and having the relay hidden like that is so cool. Looks just super clean, really great work.

cooder

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Re: 4-Knob Rat (and Lasers)
« Reply #4 on: January 28, 2019, 02:53:23 PM »
Most excellent!
What schematic did you base this on? Especially regarding to the frequency pot circuitry?
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Leevibe

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Re: 4-Knob Rat (and Lasers)
« Reply #5 on: January 28, 2019, 03:33:37 PM »
Tempting me with the laser stuff. That's a sweet face plate. Nice build all around!

323effects

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Re: 4-Knob Rat (and Lasers)
« Reply #6 on: January 28, 2019, 03:35:27 PM »
Thanks Stephan!
Used Bean's Slow Loris schem as a reference just for ease/convenience (as always, thanks for sharing freely, Brian).  But it's really just a standard Rat with adjustable Ruetz mod and LED/Si diodes on a toggle.

Ruetz mod has been around for a while... think the first time I noticed the mod with a pot goes back to the Beavis Audio days maybe (???)
Some folks' versions don't have the min resistance on the pot (R4 in the Slow Loris schem). At the moment, I believe I included that, but don't hold me to it.

323effects

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Re: 4-Knob Rat (and Lasers)
« Reply #7 on: January 28, 2019, 03:41:52 PM »
Tempting me with the laser stuff. That's a sweet face plate. Nice build all around!
Yeah I got the laser bug sometime late last year and haven't been able to shake it.  The one Igot is pretty affordable cheap. If you decide to dive in, it's not a bad place to start though.  Just know that a good etch through powder coat isn't really going to happen with this one. You might be able to mark the lighter colored boxes, but the low watt diode lasers just aren't gonna get you back to clean metal easily. There's also some creep issues with multiple passes and such. That's why the wood faceplate here... you don't want to see what happened to the powder under the plate...

mjg

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Re: 4-Knob Rat (and Lasers)
« Reply #8 on: January 28, 2019, 07:32:32 PM »
Uhh, yeah, I think we do want to see what happened under the face plate.  That's how we learn.  ;)

Nice looking build.  The wooden face plate looks classy.

pickdropper

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Re: 4-Knob Rat (and Lasers)
« Reply #9 on: January 28, 2019, 07:37:25 PM »
It's a nice looking plate.  I definitely would reduce the OD to so it doesn't go edge to edge on the enclosure.

Overall, very nice job.  Oh, and I love 4-knob Rats.
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323effects

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Re: 4-Knob Rat (and Lasers)
« Reply #10 on: January 30, 2019, 07:45:14 AM »
Uhh, yeah, I think we do want to see what happened under the face plate.  That's how we learn.  ;)

Well, since it's for science...

Makes me feel like I need to have my eyes checked  :o
I think if I had the alignment correct and just went for a darker mark, it prob could've worked.

It's a nice looking plate.  I definitely would reduce the OD to so it doesn't go edge to edge on the enclosure.
Give the people what they want!!


It's kinda strange that the seafoam looks so much more green when the plate is on. These pics were about 5 minutes apart, in the same location, with the  same lighting. Also, it's much harder than you might think to trim off a ~1/8" on this super thin wood!

TGP39

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Re: 4-Knob Rat (and Lasers)
« Reply #11 on: February 01, 2019, 03:01:06 AM »
The wood faceplate is awesome and just think of the different types of wood you could try.  I was saving for a Glowforge, but I still can't get myself to shell out $3000 for it.  I think I'll give another look at the 3 watt diode laser.  Great job all around on this build. Steve.
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323effects

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Re: 4-Knob Rat (and Lasers)
« Reply #12 on: February 01, 2019, 07:42:43 AM »
The wood faceplate is awesome and just think of the different types of wood you could try.  I was saving for a Glowforge, but I still can't get myself to shell out $3000 for it.  I think I'll give another look at the 3 watt diode laser.  Great job all around on this build. Steve.
Thanks Steve.
If you invest in a glowforge maybe you could start selling lasered enclosures to schmucks like me to make your money back!
For the wood, I stumbled on https://www.inventables.com/. They have a pretty good selection of hardwood including some more exotic stuff. The good thing about them is you can actually get pretty small quantities without paying an absolute fortune for shipping.  I picked up the cheapest stuff they had on my first order just to test with the laser, but think I might grab some zebra and wenge.

Martan

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Re: 4-Knob Rat (and Lasers)
« Reply #13 on: February 05, 2019, 05:40:22 AM »
The pedal looks great! I'm about to try some laser engraving of wood and hope it comes out so well. I just received some 1/16" padauk from http://ocoochhardwoods.com/scroll_saw_lumber.php (no affilitiation). Good selection of 1/16" stock. Shipping doubled the price, though. Recieved it and its good quality.

Marty

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Re: 4-Knob Rat (and Lasers)
« Reply #14 on: February 05, 2019, 08:09:39 AM »
The pedal looks great! I'm about to try some laser engraving of wood and hope it comes out so well. I just received some 1/16" padauk from http://ocoochhardwoods.com/scroll_saw_lumber.php (no affilitiation). Good selection of 1/16" stock. Shipping doubled the price, though. Recieved it and its good quality.

Marty

Thanks Marty! I ran across those guys at some point looking for materials too. And yeah if you're buying small quantities, shipping will definitely get ya. I went with Inventables since shipping wasn't too bad.
A bonus at Ocooch might be the fact that the boards are only 4" wide. Depending on the look you're going for you might only have to cut it once... Seems like 4" would work for the height of 1590B or 125B boxes.