Soma - LYRA-8 DIY Kit

[Addam]

I emailed Vlad about this when building my Lyra 4 and his reply was "The second pin of 5.1 ohm connected to the enclosure
- it's the grounding"

I attached to my metal case and got noise on one set of headphones and not in another. Either way - yes should be connected to chassis ground. I'll say that when I was troubleshooting the noise I tried connecting to headphone jack ground, output jack ground and other various spots with the same results.

Flounderguts and digix, check upthread a bit regarding headphone noise and impedances.

[digix]

Flounderguts and digix, check upthread a bit regarding headphone noise and impedances.

Cheers for that. From the thread I can assume that my headphone impedance is contributing to the noise. I'm not really inclined to open it up and start experimenting with grounding since the main out is nice and clean. Later down the track if I need to open it I'll give some additional grounding a try.

[Flounderguts]

Flounderguts and digix, check upthread a bit regarding headphone noise and impedances.

Yeah, I remember that. I've actually been measuring noise on the hp circuit with a scope. I have a lot of headphones with different impedance values, and I haven't gotten around to trying them. I think a small amp circuit could be an easy fix, but that's for the future.

I'm currently tracking down some intermittent voice issues, and I really think it might be the board to board connections. I'm using JST connectors instead of Dupont, but I'm really thinking of trying something else...

[Addam]

I hear you.. for me the headphone out is not that important, and will be less so on your big ass expanded version when I get to that

On my 4 I used cheapie angled pin headers from tayda and pre-made dupont jumper wires. I was a little sketched out by that (there are a lot!) and worried the connections would be weak but it ended up working out ok so far. Probably better than if I had hastily crimped a bunch of molex

[digix]

On my 4 I used cheapie angled pin headers from tayda and pre-made dupont jumper wires. I was a little sketched out by that (there are a lot!) and worried the connections would be weak but it ended up working out ok so far. Probably better than if I had hastily crimped a bunch of molex

FWIW I bought a stack of these 12pin 10cm pre-made cables from AliExpress, snipped off one side and soldered it directly to the control board. Then the connector mates to pin headers on the main board. Clean and easy.

In hindsight I probably could have used right angled pin headers on the main board (and put the big electrolytic on its side) to reduce overall height. I'm still happy with how it all came together in a case about 6.5cm deep.

https://www.aliexpress.com/item/3303066 ... 4c4dk3ShMb

[hiegdk]

Did i get this the wrong way around? Very much second guessing myself...

[gnsk]

Did i get this the wrong way around? Very much second guessing myself...

wrong way.

[hiegdk]

Did i get this the wrong way around? Very much second guessing myself...

wrong way.

Thanks. This'll be fun.

[hiegdk]

Did i get this the wrong way around? Very much second guessing myself...

wrong way.

Thanks. This'll be fun.

PS. What's the likelihood that I popped those backwards ICs when I applied power to the unit?

[Flounderguts]

PS. What's the likelihood that I popped those backwards ICs when I applied power to the unit?

They should be ok. It's a Schmitt trigger, after all.

[hiegdk]

PS. What's the likelihood that I popped those backwards ICs when I applied power to the unit?

They should be ok. It's a Schmitt trigger, after all.

Thanks!

[hiegdk]

Looks like one of my HEF4093 NXP is toast (reading 12V at all the pins so I'm guessing it's shorted internally?). Assuming that's the case any suggestions for where to get a replacement? I found this at Mouser: https://www.mouser.ca/ProductDetail/NXP ... svthfMmQ==

[t3hh]

Did i get this the wrong way around? Very much second guessing myself...

despite the reversed position, can I compliment your soldering skills. Thats an impressive precision and amount of solder.

[steviet]

Looks like one of my HEF4093 NXP is toast (reading 12V at all the pins so I'm guessing it's shorted internally?). Assuming that's the case any suggestions for where to get a replacement? I found this at Mouser: https://www.mouser.ca/ProductDetail/NXP ... svthfMmQ==

I think people in this thread have used this version to varying degrees of success (the timbre is a little different depending on the IC). But it is definitely worth a try! EDIT** looked around a bit, I think they are pretty much identical, but YMMV!

Also want to say that was a rad solder job, so clean.

[hiegdk]

Thanks t3hh & steviet!

[Bamboombaps]

Due to a combination of errors i have spares of 3 versions of panels- one with messed up silkscreen and no solder mask or copper, one with no soldermask, just bare copper which have blemishes and scuffs but shiny and cool in its own way, and some white ones, mostly ok but with some minor smudges

all holes line up with the pcb and there are holes for mounting into an enclosure

pm if interested

[hiegdk]

I ended up having to replace both of the SMD ICs that I'd installed backwards. I replaced them with ones I ordered from DigiKey here in Canada. They don't look exactly the same as the ones that came with the boards but after installing them they seem to work - I'm getting sound from each of the oscillators and the Mod, Sharp, and Tune controls seem to be working.

I'm having two issues though:

1) Neither of the Pitch knobs seem to do anything at all.
2) The delay is very noisy (hiss, static etc) when the mix is up.

Any pointers for places to start debugging either of those issues?

[LegWyne]

Fyi I asked soma about testing the NXPs recently (fried mine) and got the response that if you can get a square wave out if them with an oscilloscope the issue is probably the connected transistors. they also confirmed that NXP 4093a from any source should be fine, they're not from a particular weird batch or anything

[Flounderguts]

Anyone know why there is an extra pad leading to the AND pin? It is on the same trace as the Triangle/Square switch.

ANDPAD.jpg (43.26 KiB) Viewed 215 times

[gnsk]

Anyone know why there is an extra pad leading to the AND pin? It is on the same trace as the Triangle/Square switch.

i was also curious about it during my lfo bleeding investigation.
maybe hackable point. Anode of 4148 is from INVAND. So, could switchable AND / INVAND to LFO.
just my imagination.

[hiegdk]

Does anyone have any thoughts as to why my pitch knobs would be non-functional? ie: turning them doesn't seem to have any effect at all.

[steviet]

Does anyone have any thoughts as to why my pitch knobs would be non-functional? ie: turning them doesn't seem to have any effect at all.

I would double check the wiring, make sure there are no shorts around those pins, check continuity to the pads it leads to etc... Things I'm sure you've done so I'm sorry if that's not helpful. If the individual tuning knobs work I would assume it has something to do with the control board. Check continuity on all your headers/connectors.

If not I'd contact Vlad. I think he's pretty responsive, and he's got the schematics, so he could give better advice! Best of luck!!

[hiegdk]

Does anyone have any thoughts as to why my pitch knobs would be non-functional? ie: turning them doesn't seem to have any effect at all.

I would double check the wiring, make sure there are no shorts around those pins, check continuity to the pads it leads to etc... Things I'm sure you've done so I'm sorry if that's not helpful. If the individual tuning knobs work I would assume it has something to do with the control board. Check continuity on all your headers/connectors.

If not I'd contact Vlad. I think he's pretty responsive, and he's got the schematics, so he could give better advice! Best of luck!!

Thanks steviet, I have poked around at the control board but I'll take a closer look.

[deformative]

I'm having an issue with one of the channels on my build (oscillators 3 and 4). If I crank up the volume I can just hear them and the tuning section seems to be working as it should, so it really just seems like an amplification issue. I followed the circuit as best I could and compared to the other working oscillators and so far haven't found any discrepancies. I reworked some of the more suspect soldering and no luck. I'll give it another shot soon, but has anyone else run into this?

[steviet]

I'm having an issue with one of the channels on my build (oscillators 3 and 4). If I crank up the volume I can just hear them and the tuning section seems to be working as it should, so it really just seems like an amplification issue. I followed the circuit as best I could and compared to the other working oscillators and so far haven't found any discrepancies. I reworked some of the more suspect soldering and no luck. I'll give it another shot soon, but has anyone else run into this?

If you have some spare OP amps try swapping those out maybe!