Soma - LYRA-8 DIY Kit

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breadman
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Re: Soma - LYRA-8 DIY Kit

Post by breadman » Wed Sep 02, 2020 5:20 pm

Hey all, having some problems with a build. I initially installed the big 2200uF capacitor backwards and promptly blew it up (nice one me). With a new one installed, all the test points read just about what they should. However, the SMT 4093's each produce pretty quiet offset waveforms and the master Pitch control on 1-4 doesn't do anything (power input holds at about 1.8V off the emitter of that BC547 transistor). 5-8 are audible but the waveform is still weak and doesn't hold pitch very well. Before I desolder them, does this sound like fried 4093's, or something else?

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(BC547 is missing in this image but it's back now, this was not the problem)
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Wed Sep 02, 2020 10:48 pm

1. Looks like there is a BC547 missing (the one that connects to the SOMA logo trace)
2. Hard to tell, but there seem to be 2 or 3 bridged solders on the backside. Also, give it a scrub to remove any flux...Vlad says in the build document that it can mess with the sensitivity.

Just to make you feel better, I tried putting my (fresh build) Lyra in a different rack today, and decided to pop in a new power connector. I must have been rushing, because I got magic smoke! Fried the 5.1 ohm resistor between the ground trace and the grounded post!
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Re: Soma - LYRA-8 DIY Kit

Post by breadman » Thu Sep 03, 2020 7:57 am

Flounderguts wrote:
Wed Sep 02, 2020 10:48 pm
1. Looks like there is a BC547 missing (the one that connects to the SOMA logo trace)
2. Hard to tell, but there seem to be 2 or 3 bridged solders on the backside. Also, give it a scrub to remove any flux...Vlad says in the build document that it can mess with the sensitivity.

Just to make you feel better, I tried putting my (fresh build) Lyra in a different rack today, and decided to pop in a new power connector. I must have been rushing, because I got magic smoke! Fried the 5.1 ohm resistor between the ground trace and the grounded post!
Thanks, I had taken that picture right after I pulled that BC547 to test it--it was not the problem. It looks like that transistor controls the supply voltage on each 547 (it's going to pin 14) but on the voices that aren't sounding (1-4) this node is stuck at about 2V while the other one can go up to 8 or 9 when the Master Pitch knob turns. I'll definitely try cleaning the flux and check again for bridges and stuff, but when I fire it up it seems like the envelopes and stuff are opening, but the oscillator for 1-4 is doing some weird quiet clicking/ground hum thing. Also the "Sharp" seems to cause key 5 to only work like the others when almost fully CW; at the rest of the range it's quiet and continuous. The behavior seems so mixed up that I'm still afraid I've damaged multiple other parts. :bang:
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Re: Soma - LYRA-8 DIY Kit

Post by breadman » Thu Sep 03, 2020 7:57 am

disregard this one
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Re: Soma - LYRA-8 DIY Kit

Post by LegWyne » Thu Sep 03, 2020 10:23 am

Finally about to get this pre modded build to the point where I can power it on. I've seen mention of test points around, I can't seem to find documentation on things to test for am I missing something?

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Thu Sep 03, 2020 12:59 pm

Look at the main board...there are marked test points with voltages. 5.87 V, 2.45 V, 6V...and the power and ground rails are well marked all over the board
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Thu Sep 03, 2020 4:10 pm

breadman wrote:
Wed Sep 02, 2020 5:20 pm
Hey all, having some problems with a build. I initially installed the big 2200uF capacitor backwards and promptly blew it up (nice one me). With a new one installed, all the test points read just about what they should. However, the SMT 4093's each produce pretty quiet offset waveforms and the master Pitch control on 1-4 doesn't do anything (power input holds at about 1.8V off the emitter of that BC547 transistor). 5-8 are audible but the waveform is still weak and doesn't hold pitch very well. Before I desolder them, does this sound like fried 4093's, or something else?
Ok, so I took mine out of the rack, and I've been experimenting with it on the bench. There is definitely some weird stuff going on, and it is similar to what you are experiencing. I am actually getting sounds from the Lyra when I touch my power supply...and the voices are very quiet sometimes...especially 1 and 2.
I didn't have any problem with the LFO LED clicking before, but I do now.

The expanded voice range switch works really well, and the vibrato is nice too...but it's hard to make an overview video until things do what you halfway expect when you hit them. I also am getting radio station noise when I touch the fb or vibrato toggles!
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Re: Soma - LYRA-8 DIY Kit

Post by gnsk » Thu Sep 03, 2020 10:14 pm

Flounderguts wrote:
Thu Sep 03, 2020 4:10 pm
I didn't have any problem with the LFO LED clicking before, but I do now.
here also LFO bleeding but not from LED.
AND OR toggle in DIY PCB is MTS-102, but maybe new version v.3.3 or factory built use MTS-103 (on-off-on).
Replaced the MTS-102 to -103 and off the LFO for anti-bleeding.
It affects also the CV Voices mod, i reckon.
Flounderguts wrote:
Thu Sep 03, 2020 4:10 pm
I also am getting radio station noise when I touch the fb or vibrato toggles!
i had also noise from fb/vibrato tgl, when i touch or near to it. found the pcb pad of toggle is not grounded, so grounded it and no more Theremin.
Last edited by gnsk on Fri Sep 04, 2020 6:38 am, edited 1 time in total.

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Re: Soma - LYRA-8 DIY Kit

Post by LegWyne » Thu Sep 03, 2020 10:58 pm

Flounderguts wrote:
Thu Sep 03, 2020 12:59 pm
Look at the main board...there are marked test points with voltages. 5.87 V, 2.45 V, 6V...and the power and ground rails are well marked all over the board
I can of course see the test points. My question was regarding whether there is any existing documentation on recommended tests to conduct to check everything is working as it should be. Hard to do by ear on an experimental electronic instruments with lots of cross modulation.

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Fri Sep 04, 2020 10:47 am

gnsk, the peeps over in the factory built Lyra thread confirm that most builds have a 3 way switch in the and/or space, and that oldest models have a 2 way. We need to update the BOM to reflect that.

Did you ground the switch bodies to the ground on the board, or the ground on the chassis?

My build has aluminum standoffs that extend out to a large aluminum shield over the back of the instrument...to which I have ziptied all the expansion wires. I'm wondering if I have created the opposite effect of what I had intended?
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Fri Sep 04, 2020 10:49 am

LegWyne wrote:
Thu Sep 03, 2020 10:58 pm
Flounderguts wrote:
Thu Sep 03, 2020 12:59 pm
Look at the main board...there are marked test points with voltages. 5.87 V, 2.45 V, 6V...and the power and ground rails are well marked all over the board
I can of course see the test points. My question was regarding whether there is any existing documentation on recommended tests to conduct to check everything is working as it should be. Hard to do by ear on an experimental electronic instruments with lots of cross modulation.
Oh, sorry mate...I guess the question wasn't clear to me.
No documentation. However, between this thread and the one over at electro-music, we're starting to get a good body of work together!
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Re: Soma - LYRA-8 DIY Kit

Post by gnsk » Fri Sep 04, 2020 12:15 pm

Flounderguts wrote:
Fri Sep 04, 2020 10:47 am

Did you ground the switch bodies to the ground on the board, or the ground on the chassis?
i grounded on the board, my case is wooden.
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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Fri Sep 04, 2020 12:26 pm

Thanks! I added that picture to the resources on my webpage, if that's ok...great explanation!
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Re: Soma - LYRA-8 DIY Kit

Post by neutronarmy » Sat Sep 05, 2020 11:45 pm

Flounderguts wrote:
Fri Sep 04, 2020 10:49 am
LegWyne wrote:
Thu Sep 03, 2020 10:58 pm
Flounderguts wrote:
Thu Sep 03, 2020 12:59 pm
Look at the main board...there are marked test points with voltages. 5.87 V, 2.45 V, 6V...and the power and ground rails are well marked all over the board
I can of course see the test points. My question was regarding whether there is any existing documentation on recommended tests to conduct to check everything is working as it should be. Hard to do by ear on an experimental electronic instruments with lots of cross modulation.
Oh, sorry mate...I guess the question wasn't clear to me.
No documentation. However, between this thread and the one over at electro-music, we're starting to get a good body of work together!
Could you throw a link to the electro-music thread? I can't seem to find it. I'm working my way through a plan for my modified build; any documentation helps!

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Sun Sep 06, 2020 8:01 am

How are you modifying it?
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Re: Soma - LYRA-8 DIY Kit

Post by artilect99 » Sun Sep 06, 2020 7:29 pm

I have a chance to buy someone's Lyra-8 PCBs but seeing the gut shots of the assembled module I'm having second thoughts. Why the hell do you have to loop dupont jumpers around between the boards like that? Couldn't you solder the female headers on the main board to the opposite side, and then just connect the to the control board from underneath, using jumpers or extender pins?

Also, why the hell is the control board mounted BETWEEN the panel and the controls? That is the most backasswards things I've ever seen, no disrespect to Vlad. :sstorm: You have to kludge the entire control board using resistor legs and then mount it to the panel?? I'm trying to figure out a better way to do it from looking at the pictures but I'm guessing ppl would have already done so if it were possible.

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Sun Sep 06, 2020 9:05 pm

artilect99 wrote:
Sun Sep 06, 2020 7:29 pm
I have a chance to buy someone's Lyra-8 PCBs but seeing the gut shots of the assembled module I'm having second thoughts. Why the hell do you have to loop dupont jumpers around between the boards like that? Couldn't you solder the female headers on the main board to the opposite side, and then just connect the to the control board from underneath, using jumpers or extender pins?

Also, why the hell is the control board mounted BETWEEN the panel and the controls? That is the most backasswards things I've ever seen, no disrespect to Vlad. :sstorm: You have to kludge the entire control board using resistor legs and then mount it to the panel?? I'm trying to figure out a better way to do it from looking at the pictures but I'm guessing ppl would have already done so if it were possible.
Having played with the build a lot, it's true there are some weird ways it is put together, but it starts to make sense.

The DuPonts are not required, just the way most people prefer to do it. I used ribbons. The pins aren't lined up, so you can't do direct plug. You could use screw terminals...I thought about using a PTSM 12 pin, but they were sold out when I wanted them. The original Lyras are built with the bus wire/resistor legs, so we do ours that way. Some of us even splash out more $$ for old style carbon composition resistors, just for the look :yay:

It's certainly not a straightforward build, compared to most other DIY...it seems that non-standard PCB design goes hand-in-hand with non-standard operation...a CL Deerhorn is similarly weird (all CL stuff!) but for some of us that's part of the charm.

The soldering is actually pretty easy on it, thanks to large pads, good alignment, and slightly oversize holes. You can solder almost every component without flipping the board...a few of the caps are really the only things you can't. The shields are a bit tricky...oh yeah, you probably haven't even spotted those, yet :goo:

And there is no schematic. Troubleshooting the beast is a bit of a nightmare, as none of us really understand it well enough. Read back through the thread and you will find lots of issues with LFO bleeding through to audio, voices not sounding or not turning off, poor grounding, parts missing off the BOM, undocumented changes to things...

But it's rewarding if you do take the plunge.

I think a great deal of the design had to do with Soma's handbuilding process. It's actually quite easy to get the pots soldered in once they are holding the pcb to the front panel.

Up to you if you decide to do the build, but we're here for support if you do!
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Re: Soma - LYRA-8 DIY Kit

Post by neutronarmy » Mon Sep 07, 2020 12:31 am

Flounderguts wrote:
Sun Sep 06, 2020 8:01 am
How are you modifying it?
I'm not planning anything too wild. I'm looking to implement some of the LFO output options discussed earlier in the thread and considering either 10 turn pots or trying to kludge in a fine tune for each voice. With the PCB layout it seems adding a secondary pot would be quite a challenge, but I'm not 100% set on enclosure design, so I may just have to squeeze them around the perimeter. It's still realistically a few months down the queue, but I try to organize any documentation I can before embarking on a build. Thus, when you referenced another discussion that I wasn't actively following, I decided to reach out. Thanks for the info you've been providing!

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Re: Soma - LYRA-8 DIY Kit

Post by artilect99 » Mon Sep 07, 2020 1:01 pm

Flounderguts wrote:
Sun Sep 06, 2020 9:05 pm
It's certainly not a straightforward build
Man you can say that again. As you say tho, it goes hand in hand with the weirdness of the thing, so I'm prepared to deal with it for the sake of owning a Lyra. I've done a lot of DIY by now so my usual process is look through the BOM for anything obsolete -- no problems there -- then look at the construction... holy hell what is going on there.

I'm probably going to give it a go because I'm stupid. And I want to be able to hook it up to the Ornament when that drops!

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Re: Soma - LYRA-8 DIY Kit

Post by steviet » Mon Sep 07, 2020 2:48 pm

Flounderguts wrote:
Sun Sep 06, 2020 9:05 pm
Some of us even splash out more $$ for old style carbon composition resistors, just for the look :yay:
Who would do something like that? I'm sure if they did it was because it looks SOOOOO good. :omg:
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Re: Soma - LYRA-8 DIY Kit

Post by LegWyne » Wed Sep 09, 2020 4:37 am

Feck! Things put together (still working on an enclosure + panel) trying to troubleshoot this in the mean time. Quite a confusing electron maze to grapple with! Are these sounds supposed to happen or is it an artifact of something wrong? Hard to say in some cases.

- Grounding issues: There is definitely one and I'm not sure what to do about it. There's a low buzz that exists unless I'm touching the components. Happens on hardware except Time 2, the fast switches and Total FB and Vibrato. The last two actually make the buzzing worse when touched.

The above posts from grnsk state adding TotalFB and Vibrato to ground helped with their issues, but seeing as the buzzing gets worse for me when they are touched alongside grounded parts I'm not sure it will help in my case. Any thoughts on how to deal with this ground issue?

- Muffled spike of noise on power up, high pitch squeak on power down. both irrespective of volume level. No idea on this one. Doesn't seem too incovnenient to work around just odd behavior.

- Vibrato doesn't seem to do anything on either setting. Maybe its very subtle but I just can't hear a difference, is this true for anyone else? Tested on all 8 voices.


Other than that this thing sounds hot as heck and I am very excited to finally have a solid jam once its in a box and debugged!

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Re: Soma - LYRA-8 DIY Kit

Post by breadman » Wed Sep 09, 2020 2:10 pm

LegWyne wrote:
Wed Sep 09, 2020 4:37 am
- Muffled spike of noise on power up, high pitch squeak on power down. both irrespective of volume level. No idea on this one. Doesn't seem too incovnenient to work around just odd behavior.
The not quite working build I'm on does this too. Would love to hear if a "factory" one behaves this way.
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Re: Soma - LYRA-8 DIY Kit

Post by LegWyne » Thu Sep 10, 2020 5:16 am

ffs i think I cooked my build! The ground hum thing was driving me nuts so I flipped the board to test voltages on the test points and i connected the in out board upside down by mistake. When i realised i reconnected it the proper way and but the voices now dont sound at all... an exhausting and upsetting mistake after a lot of work. im not sure what to do at this stage!

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Thu Sep 10, 2020 3:06 pm

Check the 5.1 ohm resistor near where the ground goes to the chassis post. If it's cooked, replacing that one might revive it...
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Re: Soma - LYRA-8 DIY Kit

Post by digix » Fri Sep 11, 2020 4:38 am

OK team - I'm getting close to finishing up my build. I've noticed on the images of stock Lyra-8's the I/O board has two leads coming out from a very large solder pad. Nothing is listed in the documentation about it. What's this about? Just ignore it?
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