Hi guys, first time posting here. New to module building but excited to jump in.
I note the BOM links to some stereo jacks, and I have a bunch of mono jack’s here as pictured.
Are these going to be fine for the build, with the jack tip going to the square pin and the sleeve going to the north pin?
What are the other three pins for?
And also what are the two smaller sized pins next to J5, 7, 9, 11, 13 and 16? Edit: ignore this question…I turned the board over and see they’re for resistors on the other side
These are commonly used in Kosmo modules even though usually only the sleeve, tip, and maybe tip normal pins are used. The #2700 doesn’t use the tip normals, so your 2-pin jacks should be fine. But the sleeve pin goes to the square pad, not the tip pin.
In this image you can see Sam hasn’t even soldered the other 3 pins:
to back up what analogoutput these will work!
also it looks like you have the larger pads that dont fit through the hole, with some snips I recon you can make these small enough to fit! but yeah the sleeve which is usually signified to be the pad on the corner of the jack that seems to be set at a slant. that goes to the square pad which is ground.
Thanks both! I’d had a gander at that particular photo and that’s what prompted me thinking… there’s clearly five pins in that photo and my jacks have only got two! Best to ask before I have to desolder anything
I’d plonked a jack down and it fit very nicely with the sleeve in the north pin and tip in the square pin, so again I made an assumption there. Thanks for pointing out I should be rotating, the jacks now fit square with the board.
This thing is driving me crazy. At first I was getting a lot of intense tones (no inputs) which seemed to stop when testing voltage over the 4011. After butchering the 4011 in the process (all the legs fell off then it flew across the room), I realised it was not the problem and is still working (new legs attached). I then did what should have been step 1 and read the forum where Riggidyboo pointed out above that there was noise until they adjusted each drum sound.
So… I’ve turned all the 1M trimmers to the far left and started there.
I can get a kik, lbongo and hbongo with decay when using the pots.
The clave is sort of there but any adjustment on the pots and trimmer caused a high pitched feedback.
The snare sounds like the lbongo and any adjustment on the pot/trimmer causes the same high pitched feedback
The noise is silent
Does anyone know if there is a method of calibrating the trimmers to get it set up as nothing I’m doing is working? With the noise being silent, I starting to think there is something else maybe going on.
I think I have two problems here. The calibration gets rid of the feedback (thanks for the message and help) but there is still no audio on the noise. I guess it makes sense that the snare sounds like the lbongo as its combining the lbongo and the noise, but without the noise working its not snaring.
Its very strange. I’ve got good connectivity on everything I’m testing but there is only a very slight voltage on leg 2 of Q1 (0.06V) and on leg 2 of Q3 (0.2V). I took the sensible approach and randomly jammed a resistor between legs 2 and 3 of Q1 and got a white noise on the speaker. With input voltage at D7 I’m now guessing the problem is somewhere between D7 and Q1 which leads to probably C5. If only I could remember which one was C5.
So… I can’t find the answer. I’ve just about given up.
Replaced C5 and Q1. Connectivity seems all good and no grounds where there shouldn’t be any and all those have the correct resistance. I’m getting good voltage on the C5 leg (on the input side) on a pulse in, but only 0.02V on leg 2 of Q1. My only thought was that there was a ground somewhere taking the voltage, but the resistance between C5 and Q1 is the 27k as it should be.
Started looking upstream of Q1 figuring that a ground could be there. Can’t find anything. Replaced the choke, changed the 074CN’s, replaced both Q2 and Q3. Nothing. No noise to make my snare less bongo.
12V at the Choke. 11ishV on leg1 of Q2 and Q3. 0.02V on leg 2 of Q1. 0.2V on leg 2 of Q3. Even less on leg 2 of Q2.
@lookmumnocomputer & @Riggidyboo , i try to make it and i think there’s a little mistake in the BOM, only one 4n7 cap, and there are 4 in reality/schematic
Yes that’s for sure, but for example when I order a lot of components (often for around 15/20 modules at once), sometimes I order just what it takes to build a module (especially if it’s values not very common) and there I made a mistake with the quantity i’ve seen in the BOM.
Yes infact it is 3
so I thought it was good to specify it to maybe also rectify it in the forum, to prevent it from happening to another
if you say before in another comment the noise is working, maybe its in the mixer??? is there no snare in both the mixed together output aswell as the snare output??
thanks dud will fix. I think it happened because earlier someone commented the BOM had both 4n7 and 4.7nf specified,iprobabbly fixed it by removing one and forgot to update the quantity of the other
A pulse into the snare gives off the lowbongo beat only and a pulse into the noise gives off no sound at all. I started thinking I was doing something wrong, but the vid shows a pulse into the noise jack giving a similar snare(y) like noise.
I’ve switched out more parts today in the noise circuit, but nothing. The noise led lights up, so it’s definitely something after D7. I’m not exactly knowledgable on what’s going on in the circuit. I was thinking that leg 2 of Q1 would need to go high to start the trigger of the noise (and c5 would give it a bit of a snap), but there is only a flicker of 0.02v on the leg. I’ve used a wire to connect the input pulse directly onto leg 2 of q1 and I get a mid volume very plain hiss for the whole pulse in.
I’ve just pulled resistor r57 to disconnect it from the mixbus and still no noise. I’m confident that it’s all good at the tl074 because of the hiss sound I get when shorting out q1.
Ok…… i did a bit of Googling last night and learned about producing white noise from putting voltage into the emitter of a transistor. I also now know why a capacitor is put in series with the base of a transistor as we don’t do DC.
I then remembers some saying (from Sherlock or somewhere) which goes along the lines of…
If you eliminate all the impossible… keep banging your head against the wall and definitely don’t try anything other than what you’ve already tried 100 times.
So it got me thinking that I should maybe try something different. So I put 12v onto D7 and got a snare(y) noise. I put 5 volts from the nand ic onto D7 and got the snare(y) noise. I think my problem was that i was using the #1145 VCLFO to make the pulse in (because it lives next door in the case) and it’s only giving out about 2.5ish volts. So I’m thinking the C5 and R15, R40 setup does not like the lower trigger voltages, but the other drum sounds capacitor/resistor setup do and were firing.
So I think this may be solved. I might switch out C5, R15 & R40 for different values to get it working at the lower voltages (possibly one similar to another drum), but at this stage I think my board is just about sick of me messing with it. Looking at my injured 4011 ic, it’s eyes are telling not to.
A (which is the pre-JEDEC version from the 70s, no longer produced) and UBE both work, but you may need to tweak some resistor values for the UBE. See Sam’s update here:
