Finally getting on with my mixer build. Hopefully test before this weekend.
Already have one problem that will make me reprint after testing:
The circuit and controls are all on one board, courtesy of jlc smt service. They do a good job and doesn’t take much longer than bare pcbs
Cool stuff!
How much was the Placement and components in total?
I built a little night light for my niece who was born 2 weeks ago 
It’s made from a broken foot switch and 3 LEDs driven by a 555 dimmer circuit. I was tempted to add the APC circuitry since I already had a 555, but I guess that’s not too useful in a night light 
Nice red light (maybe the APC as a lullaby 
)
I’ve just finish (only the circuit, soon i will have to start the panels) my Dual Balter gate delay (from NLC)
i add a switch on the second one to select 1uf or 10uf for very long delay.
$20 each for two boards, plus the normal print cost, $5 for these. I have like 5 or 6 ‘extended parts’ which cost more.
Considering there is a tl072, 4x tl074, a headphone amp ic plus dozens of diodes and resistors, I think it’s fair price for the amount of time it will save
Which headphone amp IC? In case my current headphone thing doesn’t work out. Was that an ‘extended part’?
Also, you can have just two boards assembled?
Lm4808 if I remember right. Seemed fine on breadboard. I also did the design with two ne5532 which sounded the same to me.
It was an extended part, I think 50c charge to bring it to the line.
Yes u can have just 2 assembled or 5. You still get the 3 extra unassembled boards tho. So probably best to make sure your design works before and then print 5
LM4808 is what I have on a pain in the butt design I’ve been avoiding working on. If I get it working, great, but the extra boards go to the trash, neither I nor anyone else will want to use them. If not then I’ll do a redesign. Not the LM4808’s fault other than my having more trouble than expected getting it soldered down, the design flaws are elsewhere.
Did up the buffer board for the brute, seems to be working!
Made a couple mistakes and thought that I had realized my worst fear for a bit…
I’ve been pretty nervous about working on this thing - I knew I wanted to do it when I got it, but have spent the last ten months doing eurorack projects to build up the confidence to work on it. If I messed something up and fried it I’d be pretty upset.
After hooking up my buffer board I powered up the Minibrute and lights came on but I was getting no signal from the outputs on the board. Switch midi channels on my keyboard in case I accidentally changed it, nothing. Plug in headphones to the Brute in case it’s just the board, nothing, no output. Hook the keyboard back up in case it’s a MIDI problem after all, nothing. Give a close look at everything again and realize that I had a brain fart and mixed up the +12v and -12v signals going from the Minibrute board to my buffer board. This is where my panic set in. I can (usually) follow instructions, but I don’t know enough here to understand the ramifications of something like this, but the Minibrute not functioning had me sweating. Desolder the wires from the Minibrute to my board, fire it up with fingers crossed and woohoo! The Minibrute seems to be unharmed! Resolder the wires back up properly, and now the buffer board is working too! Woooooo! Can’t remember the last time I felt this relieved.
At that point I shut it down for the night. Resumed work this morning, finished soldering between the Brute and the buffer for the oscillator wavforms out. This is where mistake 2 came in to play. I don’t think you can really see too well in the picture, but the smaller and bigger boards on the Minibrute are connected in a few different spots, and almost all of the ribbon cables are hot glued into place on the headers, so I can’t remove them. You can see my one white wire going up under the small board on the right hand side - after unscrewing the upper board from the case, there is only so much extra room you can get to work before the wires max out their length. One test pad was extremely hard to access and I had a very tough time holding the board out of the way while soldering my wire to it and I think at the end of it the pad lifted and is now gone. Fortunately, if I was going to lose an output, this is a good one to go - it’s listed as “first mixer stage folded triangle” on the megabrute.com site and “first mixer stage folded triangle” in the Leafcutter Mods docs. I was only taking it out more or less “just because” - it’s not something I actually need. So - lesson learned, need to be more careful with these test points.
brave man hacking into that
It is very well documented and my understanding that it’s one of the easiest synths to mod like this. It’s my first and only synth outside of the eurorack so I don’t know that from experience - just what I’ve read!
Did a quick and dirty side panels for it today. More or less eyeballed them based off the side panels and they’re a bit long, so I’ll probably take em back to the shop tomorrow.
I routed out a bunch of the side panel on the side I’m mounting the buffer board and was planning to mount my jacks there, but now I’m thinking I should re-do them with a larger flat front bottom, then put a piece of wood across and do them there… Will need to think on it. For now, I can just pop the jacks out the bottom.
Nice! I’ve made similar ones as Christmas tree lights and for a family tree with images of my relatives in them. Have a look at: lithophane maker.
Just finished printing a bracket for my K-2.
My buddy pulled this Yamaha PSR-330 out of his mother’s basement. It’s a pretty nice keyboard. No aftertouch, but very good velocity sense.
And yes, I know the keyboard can make plenty of sounds on its own… But I wanted the K-2.
" But I wanted the … " .
we know that feeling .
I’ve tried a few MS20 filter kits, and they’re ok, but they’re never quite as awesome. I’m not smart enough to know why. Maybe it’s the reworking to make them track 1v per oct, maybe the transistors are out of speck…
Finally broke down and got the K-2. She screams. These filters and Sam’s Grrrs are hands down the best I’ve got.
Opamps arrived in the mail, finally finished up Bassline! By far the most components and most sense build I’ve done so far. Hard to imagine a denser board actually, though I’m sure they’re out there…
Haven’t done any calibration yet as I ran out of time, but quickly testing it looks like everything works as expected!
Will do calibration in the morning and dig into it over the weekend, hopefully knobs will show up in the next week or two.
That build is definitely a doozy. Let me know how your subosc is working. There is an Intermittent problem with mine.
Will you publish the bracket (e.g. to thingiverse) or are they specifically adapted to this keyboard?
