Soma - LYRA-8 DIY Kit

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klenkstar
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Re: Soma - LYRA-8 DIY Kit

Post by klenkstar » Fri Oct 16, 2020 4:54 pm

I'm having some trouble figuring out the best way to mount the control panel on the flunderton face plate (great looking plate btw!). With m4 standoffs I needed a nylon washer to fit the hole size on the board. Is it best to double up on the nylon washers for each of the pots/switches ? Also how are you folks keeping the washers in place for the thumbscrew pads when putting the front panel on? tape? There doesn't seem to be an easy answer here or i'm just overthinking it.

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Re: Soma - LYRA-8 DIY Kit

Post by steviet » Fri Oct 16, 2020 5:34 pm

I posted about this exact thing on my blog! I first did what you mentioned, I added Nylon washers because I didn't want to drill through the panel to mount it. (Drilling through the panel is an option, flounderguts added markings on the back of the panel to do this)

This ended up causing the board to flex in areas I didn't have enough washers (mainly near the thumbscrew pads). So, I decided to leave the front panel sitting on the standoffs without being secured to it and just attached the panel flat to the control board. Once it is in a case it really won't make a difference whether or not the panel is secured to the control board, but I did secure the control board to the mainboard. EDIT: I lied, the control board/panel are just sitting on top of the hex nuts attached the mainboard in my build, sorry!

Thinking back now, I could have added the nylon washers to the thumbscrews as well, but hey, hindsight is 20/20. I'm super happy with the way it turned out though, so I'm definitely going to leave it as is.

Hopefully that helps! As far as the thumbscrew pads, I'm not sure I understand. I waited until the rest of the panel was secured, and then I added the thumb screws after, with a nut underneath the panel to keep them secure and making contact with the contact points.

Let me know if that helps! Best of luck :sb:
Last edited by steviet on Fri Oct 16, 2020 5:59 pm, edited 1 time in total.
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klenkstar
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Re: Soma - LYRA-8 DIY Kit

Post by klenkstar » Fri Oct 16, 2020 5:42 pm

steviet wrote:
Fri Oct 16, 2020 5:34 pm

This ended up causing the board to flex in areas I didn't have enough washers (mainly near the thumbscrew pads). So, I decided to leave the front panel sitting on the standoffs without being secured to it and just attached the panel flat to the control board. Once it is in a case it really won't make a difference whether or not the panel is secured to the control board, but I did secure the control board to the mainboard.
Hey thanks for the quick answer. can you clarify what you mean when you say you secure the main board to the control board? How did you do this without having the screw head creating a gap on the panel side of the control board?

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Re: Soma - LYRA-8 DIY Kit

Post by steviet » Fri Oct 16, 2020 5:57 pm

Sorry if I wasn't clear! After re-reading what I posted, I mis-spoke. I didn't secure the mainboard to the control board/panel. The panel/control board just sit on top on the hex standoffs on the main board.

Image

The control board and the panel are not secured together by anything other than the switches and pots, which is more than enough for it to be connected securely.

Sorry for the confusion! I'm going to tidy up my original post there to avoid further confusion.
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Fri Oct 16, 2020 6:31 pm

Yeah, most pots and switches have a deep enough bushing to screw the two panels together.

By itself, the front panel is pretty flexy. Once you basically bolt them together using all the switches and pots, it stiffens up a lot!

If you look through the build guide for the expanded panel, you can see how I did it...I fastened all the pots and switches FIRST, so that I could control the depth of each for the knobs. In my case, I found that one nut OR 2 washers on the control board side left me enough threads to put the nut on for a good bite, but minimum stick-out of the pot shafts.
As for the switches, I adjusted the panel side nut to have 1 thread showing above the nut, and then tightened the inside nut.

If you look at your switches, there is a groove to key them. You should always mount your switches with this groove facing DOWN (or towards the off side) for correct polarity/switching action.

As for the posts to mount the main board above the control, I marked the places if you want to drill, but I used a bit of JB Weld epoxy and stuck pcb standoffs in the holes. I recommend using metal ones, as I'm not sure the Nylon posts will stick very well. Obviously I mounted them with the female side down (we should probably explore that terminology, huh?) so that I could simply place the main board on the bolt side, and put nuts on.

I'd like to point out that the original Lyra case is metal, and the flundrton panels are FR4, so that they don't conduct. The nice thing about this is that you don't have to isolate the DIN screws from the chassis (although I did, using flanged nylon washers)...but you DO have to connect your metal standoff to the metal chassis, or the negative pole on the power input. Mine is in a rack, so I have the chassis ground connected to the rack itself, and thus to the AC ground. I used a crimped ring terminal on the post connected to the 5.1 ohm resistor at the lower left side of the main board. I'm in the process of connecting the large pad on the IO pcb to the same point, as well as the ground common on the control pcb...and a direct ground from the green LED to the power negative pole (for which I am experimenting with a bit of shielded conductor)

Some of you know that I'm working on an enclosure that fits my standard front panel. On that one, the IO will connect to the IO back panel, and the main will standoff of the BOTTOM, so that there is no need to drill or glue. I'm trying to avoid using a custom cut bottom panel, which is why there's a bit of a delay...
----------------------

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klenkstar
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Re: Soma - LYRA-8 DIY Kit

Post by klenkstar » Fri Oct 16, 2020 7:16 pm

@steviet Oh! haha thank you for clarifying, that's what I thought you were saying but just wanted to be sure before I go ahead. I was thinking of doing just that so I'm glad you can confirm that there is no issue doing it that way.

@Flounderguts Thank you for these added details. You answered my next question about proper grounding too! also turns out half my switches are not mounted the correct direction with the key facing down...dang.

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Re: Soma - LYRA-8 DIY Kit

Post by grm » Sat Oct 17, 2020 1:28 pm

ok, now i am hopefully recovered from the first slight frustration that i have experienced. exhale! now, i hope i find some hints for trouble-shooting.

the problem is in the MOD section of the oscillator pairs. it clearly does not work as should, when the MOD SOURCE toggles are in the LFO/FB/CV position. then even though the sounds changes slightly when engaged (in a static way), changing the RATE of the LFO has not effect on the MODulation. the more the MOD pot is turned clock wise the more the pitch of the oscillator goes down, from about 12 o'clock, it has a very low pitch and depending on the initial FREQUENCY setting of the oscillator 'chokes' completely.

when the MOD toggle is in the upwards 'FM' position, the MODULATION pot has a very similar, if not the same effect on the oscillator as described above.

the LFO works when modulating the DELAY and all other functions work fine and sound great. i am not sure with the TOTAL FB, is working as it should and i have not tried out external inputs as modulation sources.

as always any help very welcome. without a schematic, i am completely helpless with this complex circuit.

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Re: Soma - LYRA-8 DIY Kit

Post by jkammerl » Sat Oct 24, 2020 5:31 am

I believe I'm having the exact same problem than you grm. The lfo does modulate the delay but it doesn't seem to modulate the oscillator pairs at all. When the MOD SOURCE toggles are in the LFO/FB/CV position, the sound changes is a static way, no modulation is applied.

Does anyone have any suggestions how to debug the lfo signal path?
Has anyone experienced a similar behavior and found a fix? Any comments, suggestions etc. how to get to the bottom of this issue are greatly appreciated! Thanks in advance!

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Re: Soma - LYRA-8 DIY Kit

Post by steviet » Sat Oct 24, 2020 11:29 am

Check continuity on your headers between control board and main board along the bottom near the touch pads. Specifically the PCH1 PCH3 PCH5 and PCH7. If the LFO section is working for delay its just not getting to the voices properly for some reason. I'd start there. If that is all good, head back to the main board and check around those headers there too.

Best of luck!! :sb:

EDIT: also, some pictures of your boards wouldn't hurt for troubleshooting with you! :cloud:
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Re: Soma - LYRA-8 DIY Kit

Post by jkammerl » Sat Oct 24, 2020 6:43 pm

Thanks for the quick response! I found the problem.. The LFO signal first goes to the IO board (since it can be replaced with an external CV modulation source). There I found a problem with the header on the control board side. Once I fixed it, everything worked!

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Re: Soma - LYRA-8 DIY Kit

Post by steviet » Sat Oct 24, 2020 7:33 pm

jkammerl wrote:
Sat Oct 24, 2020 6:43 pm
Thanks for the quick response! I found the problem.. The LFO signal first goes to the IO board (since it can be replaced with an external CV modulation source). There I found a problem with the header on the control board side. Once I fixed it, everything worked!
:sb: :sb: :sb: :sb:
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Re: Soma - LYRA-8 DIY Kit

Post by grm » Thu Nov 05, 2020 2:36 pm

steviet wrote:
Sat Oct 24, 2020 11:29 am
Check continuity on your headers between control board and main board along the bottom near the touch pads. Specifically the PCH1 PCH3 PCH5 and PCH7. If the LFO section is working for delay its just not getting to the voices properly for some reason. I'd start there. If that is all good, head back to the main board and check around those headers there too.

Best of luck!! :sb:

EDIT: also, some pictures of your boards wouldn't hurt for troubleshooting with you! :cloud:
thank you very much for your reply.

i've tested the continuity of the header pins you've mentioned, they seem all ok.
i've checked all other pins on those headers as well and all are good.

would pictures of the whole board be helpful or specific sections?

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Re: Soma - LYRA-8 DIY Kit

Post by grm » Thu Nov 05, 2020 3:13 pm

jkammerl wrote:
Sat Oct 24, 2020 6:43 pm
Thanks for the quick response! I found the problem.. The LFO signal first goes to the IO board (since it can be replaced with an external CV modulation source). There I found a problem with the header on the control board side. Once I fixed it, everything worked!
great that you found the source of the problem, maybe that is the same issue as i have.
could you please specify where the problem on your build was?
i have checked continuity and that is ok for all pins.
and
DLY IN is connected to the input pin (tip) of the CV DELAY socket.
DLY.SOURCE is connected to the switch pin of the CV DELAY socket.

and here's hopefully useful pictures of the full mainboard and the I/O board.
(one thing i can spot is a slightly melted 470nF cap, that i touched with my soldering iron, but usually they survive when it happened before. or could that be it?)
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Sat Nov 14, 2020 10:18 pm

I spent a good part of the day troubleshooting several builds, and playing with some LFO LED mods.

First of all, in EVERY CASE troubleshooting builds, there were no errors or bad solders. It was always bad connections at the headers. In one case, someone who was absolutely convinced it was a blown or bad NXP4093 sent me their synth. I latched the voices on, and wiggled the headers, only to find 1 to 4 were intermittent...with bad connections either on the PAD pins or the IC pins.

I've been modding mine a bit, and while I haven't been able to eliminate the LFO "bleed through," I have been able to *manage it* a bit.

My original build had a diffuse green LED on the LFO section. After a bit of experimentation, I discovered that bright LEDs with high MCV values were a bit quieter. I installed a pink one with a trimpot in place of the 30K resistor. By trimming down to a very low resistance level, the click sound went down to a bit more of a "thump." It still is very present when using the LFO. Putting a 3 way MTS-103 switch in place of the 102 called out on the silkscreen enables you to eliminate the click almost entirely (you can hear it, but very quiet unless the gain is way up) when in the center position.

One advantage to using a brighter LED is that when you have the switch in the AND position, you can see several levels of brighness...I prefer it.

One of the big advantages to the "voice" mods is that you can tune your voices into registers where the mods are more easily controlled. The vibrato is quite muted when you are near the extremes of the TUNE pots. By moving the voice register a bit with the mod, you can make sure the pitch is in the middle, and the vibrato really whelps if you want it to.

Tomorrow I will be trying some new values in the offset resistors on attack and release mods. They work really well, but I feel like I want a bit more attach range, and there is an uncontrollable zone between fast release and slow release values.

The vibrato values are pretty good, but I might change voices 5-8 to have the same bridge resistors as 1-4 and see if that sounds a bit better for me.

The most difficult thing I find with running my Lyra 8+ is the radical difference in output gain between the LFO CV settings and the FB toggle.
----------------------

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Re: Soma - LYRA-8 DIY Kit

Post by pendergast » Sat Nov 14, 2020 10:27 pm

My experience so far has been positive, in this that as I have never listened or manipulated the actual non-diy item, I have no idea what I am missing. I made a decision: either I find contentment with what I have or get the cash to get the rel thing and compare...

I like the actual madness; it is non-reliable, chaotic, pushing away some psychologic and logical enveloppes to a point that I know I have some stochastic beats in my hands. The joy of DIY is that I can make mods and probably, like one of those 10000 monkeys typing on typewriters, get it 'right' from an outsider's perspective, yet, find solace in the ongoing, never ending, exploration.

YMMV.

PS: boxing it this week.

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Re: Soma - LYRA-8 DIY Kit

Post by chopsuey5540 » Sun Nov 15, 2020 10:17 am

Just finished assembling mine and it sounds amazing!! :love:
IMG_20201115_151119686.jpg
I just have a couple of questions for the final assembly and boxing. I am handy-ish with electronics and soldering but have 0 experience with all the mechanical stuff. I've read the whole thread and was thinking of buying the mouser aluminium enclosure (part 546-1444-12123), but then how do go about drilling the front panel and other holes for the screws? Do I just send the front panel (schaeffer?) somewhere else to get it drilled and printed?

Also, I've done some quick testing and it sounds mostly fine from what I can tell, except when I turn the pots there is this kind of scratching noise as I turn them, that stops when I stop turning. Is it because the pots I bought are shit? (bought the Tayda ones btw)

Sorry if my questions are vague but this is my first build so have no idea what I'm doing in those final steps...
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Re: Soma - LYRA-8 DIY Kit

Post by Lanark » Mon Nov 16, 2020 4:59 am

Might be a dumb question but have just about finished the main board and am looking ahead at wiring - the in/out board has ph_out and ph_ground for (I’m assuming) headphones, so with a stereo 3.5mm jack would I solder two separate wires for the jack tip and ring from the one ph_out pad, with the separate wire for ground?

Edit: just seen a photo where the tip lug is wired, ground lug is wired and ring lug isn’t wired. Is that it? Would both left and right headphones get sound that way?

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Re: Soma - LYRA-8 DIY Kit

Post by gnsk » Mon Nov 16, 2020 9:43 am

Lanark wrote:
Mon Nov 16, 2020 4:59 am
Might be a dumb question but have just about finished the main board and am looking ahead at wiring - the in/out board has ph_out and ph_ground for (I’m assuming) headphones, so with a stereo 3.5mm jack would I solder two separate wires for the jack tip and ring from the one ph_out pad, with the separate wire for ground?

Edit: just seen a photo where the tip lug is wired, ground lug is wired and ring lug isn’t wired. Is that it? Would both left and right headphones get sound that way?
TRS;
T=R=ph_out (no need via two wires)
S=ph_ground

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Re: Soma - LYRA-8 DIY Kit

Post by Lanark » Mon Nov 16, 2020 11:24 am

gnsk wrote:
Mon Nov 16, 2020 9:43 am
Lanark wrote:
Mon Nov 16, 2020 4:59 am
Might be a dumb question but have just about finished the main board and am looking ahead at wiring - the in/out board has ph_out and ph_ground for (I’m assuming) headphones, so with a stereo 3.5mm jack would I solder two separate wires for the jack tip and ring from the one ph_out pad, with the separate wire for ground?

Edit: just seen a photo where the tip lug is wired, ground lug is wired and ring lug isn’t wired. Is that it? Would both left and right headphones get sound that way?
TRS;
T=R=ph_out (no need via two wires)
S=ph_ground
Thanks for the reply, I’m not sure I understand what you mean though? Are you saying that I just solder one wire to the ring lug from ph_ground, and nothing else (apart from connecting the sleeve to ground)?

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Re: Soma - LYRA-8 DIY Kit

Post by t3hh » Mon Nov 16, 2020 3:44 pm

chopsuey5540 wrote:
Sun Nov 15, 2020 10:17 am
when I turn the pots there is this kind of scratching noise as I turn them, that stops when I stop turning. Is it because the pots I bought are shit? .
you can spray the contact cleaner into the pots, this will make miracles. Probably been in high humidity warehouse for tad too long..

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Mon Nov 16, 2020 5:17 pm

Lanark wrote:
Mon Nov 16, 2020 11:24 am
gnsk wrote:
Mon Nov 16, 2020 9:43 am
Lanark wrote:
Mon Nov 16, 2020 4:59 am
Might be a dumb question but have just about finished the main board and am looking ahead at wiring - the in/out board has ph_out and ph_ground for (I’m assuming) headphones, so with a stereo 3.5mm jack would I solder two separate wires for the jack tip and ring from the one ph_out pad, with the separate wire for ground?

Edit: just seen a photo where the tip lug is wired, ground lug is wired and ring lug isn’t wired. Is that it? Would both left and right headphones get sound that way?
TRS;
T=R=ph_out (no need via two wires)
S=ph_ground
Thanks for the reply, I’m not sure I understand what you mean though? Are you saying that I just solder one wire to the ring lug from ph_ground, and nothing else (apart from connecting the sleeve to ground)?
Solder the sleeve to the ground, tip to the pos. Don't worry about the ring. If you plug a stereo headphone plug in, it should contact both the ring and the tip, giving you monaural sound in both ears. If it bugs you, you can jumper the ring to the tip, but if you plug a mono TS plug into the headphone jack, it will short tip to ground at the ring.

If you do plan to use headphones with the Lyra, I recommend going into a mixer or interface, and then listening off of that.
----------------------

Flounderguts

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Re: Soma - LYRA-8 DIY Kit

Post by Lanark » Mon Nov 16, 2020 6:02 pm

Flounderguts wrote:
Mon Nov 16, 2020 5:17 pm
Lanark wrote:
Mon Nov 16, 2020 11:24 am
gnsk wrote:
Mon Nov 16, 2020 9:43 am
Lanark wrote:
Mon Nov 16, 2020 4:59 am
Might be a dumb question but have just about finished the main board and am looking ahead at wiring - the in/out board has ph_out and ph_ground for (I’m assuming) headphones, so with a stereo 3.5mm jack would I solder two separate wires for the jack tip and ring from the one ph_out pad, with the separate wire for ground?

Edit: just seen a photo where the tip lug is wired, ground lug is wired and ring lug isn’t wired. Is that it? Would both left and right headphones get sound that way?
TRS;
T=R=ph_out (no need via two wires)
S=ph_ground
Thanks for the reply, I’m not sure I understand what you mean though? Are you saying that I just solder one wire to the ring lug from ph_ground, and nothing else (apart from connecting the sleeve to ground)?
Solder the sleeve to the ground, tip to the pos. Don't worry about the ring. If you plug a stereo headphone plug in, it should contact both the ring and the tip, giving you monaural sound in both ears. If it bugs you, you can jumper the ring to the tip, but if you plug a mono TS plug into the headphone jack, it will short tip to ground at the ring.

If you do plan to use headphones with the Lyra, I recommend going into a mixer or interface, and then listening off of that.
Thanks, that’s really helpful. Should be able to get it finished this weekend now I know 👍🏻

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Re: Soma - LYRA-8 DIY Kit

Post by deformative » Sat Nov 21, 2020 7:24 pm

deformative wrote:
Sun Oct 11, 2020 10:04 pm
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?
I think I located my problem(s). I had a few flipped caps, which interestingly did not correct the problem, but could have caused others. I have bad zener diodes on these channels. Of course, I don't have any more in stock. I have some voltage rectifier diodes (1N5817 and 1N4001). Can either of these be used as a substitute? Otherwise I'll wait it out and do a mouser order. Not having a schematic is driving me nuts.

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Re: Soma - LYRA-8 DIY Kit

Post by t3hh » Sun Nov 22, 2020 5:17 am

deformative wrote:
Sat Nov 21, 2020 7:24 pm
Not having a schematic is driving me nuts.
weren't you able to download the documentation from Soma page?

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Re: Soma - LYRA-8 DIY Kit

Post by grm » Tue Nov 24, 2020 7:01 pm

grm wrote:
Thu Nov 05, 2020 3:13 pm
jkammerl wrote:
Sat Oct 24, 2020 6:43 pm
Thanks for the quick response! I found the problem.. The LFO signal first goes to the IO board (since it can be replaced with an external CV modulation source). There I found a problem with the header on the control board side. Once I fixed it, everything worked!
great that you found the source of the problem, maybe that is the same issue as i have.
could you please specify where the problem on your build was?
i have checked continuity and that is ok for all pins.
and
DLY IN is connected to the input pin (tip) of the CV DELAY socket.
DLY.SOURCE is connected to the switch pin of the CV DELAY socket.

and here's hopefully useful pictures of the full mainboard and the I/O board.
(one thing i can spot is a slightly melted 470nF cap, that i touched with my soldering iron, but usually they survive when it happened before. or could that be it?)
anyone? :roll:

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