Soma - LYRA-8 DIY Kit

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autodafe
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Re: Soma - LYRA-8 DIY Kit

Post by autodafe » Fri Feb 19, 2021 3:53 am

After checking everything possible, I think I solved my issue with PITCH opening all voices 5- to 8

I din't put plastic washers under the small "pad" screws because "hey, the panel is made of PCB material, it's not conductive".
Well, I don't know what happened, maybe the DIN Screws scratched the silskcreen paint just enough to touch the ground plane below, maybe there was some paint issue on the panel, but putting plastic washers under the pads seems to solve the bleeding issue.
Now I only have a very small bleed when turning the PITCH knob, but that happens on voices 1-4 as well...

HenryBurlingame
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Re: Soma - LYRA-8 DIY Kit

Post by HenryBurlingame » Mon Feb 22, 2021 1:10 am

Hey all, what are the most recent lyra-8 board revisions for the three boards (main board, control board, and the small breakout board)?
FS: JMT SRV-1 Spring Reverb: viewtopic.php?f=74&t=238432

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mutronic
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Re: Soma - LYRA-8 DIY Kit

Post by mutronic » Mon Feb 22, 2021 9:08 pm

So after tearing the damn thing apart again I found the culprit to all my voice/pad problems - solder joints on the connectors. All pads are ago.

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Re: Soma - LYRA-8 DIY Kit

Post by mutronic » Mon Feb 22, 2021 9:12 pm

HenryBurlingame wrote:
Mon Feb 22, 2021 1:10 am
Hey all, what are the most recent lyra-8 board revisions for the three boards (main board, control board, and the small breakout board)?
The board I received that I believe was the last ones he sent out is a v2.6.

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Tue Feb 23, 2021 10:04 am

Yes, current factory units are 3.3/3.4, but they use different board to board connections and pots are not on the backplane.
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Re: Soma - LYRA-8 DIY Kit

Post by HenryBurlingame » Tue Feb 23, 2021 1:06 pm

Flounderguts wrote:
Tue Feb 23, 2021 10:04 am
Yes, current factory units are 3.3/3.4, but they use different board to board connections and pots are not on the backplane.
Oh, interesting, so the current factory boards are different than the current DIY ones?

Do you know how long they have been using the rev. 3.3/3.4 boards?
FS: JMT SRV-1 Spring Reverb: viewtopic.php?f=74&t=238432

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Re: Soma - LYRA-8 DIY Kit

Post by Flounderguts » Tue Feb 23, 2021 8:04 pm

HenryBurlingame wrote:
Tue Feb 23, 2021 1:06 pm

Oh, interesting, so the current factory boards are different than the current DIY ones?

Do you know how long they have been using the rev. 3.3/3.4 boards?
No idea, but probably since Sound Machines has been doing the manufacturing. There are no major differences in the design, other than some alternative parts and footprints. The distortion cap is SMT, and the NXP 4093's have both DIP and SOIC footprints. The IO board has footprints for the on/off switch and a headphone jack. Also, there is a ferrite choke on the IO board that is on the V2.2 boards, but not on the DIY boards. The 47 nF caps on the opamps are film, instead of ceramic. The major difference is the board to board connectors, which are arduino-style long pin connectors which are lined up...which is the best part, because the #1 issue with DIY builds has to do with those connections. There are some minor placement tweaks for decoupling caps on the 4093 BEAT ic...but I couldn't find any actual differences in the circuit layout.

The control board is much tidier, and there are some parts that are a bit different from the Official DIY BOM, but to my knowledge they have all been documented in this thread.

A solid DIY build acts exactly like the factory instrument, although there is an intermittent appearance (in some builds) of excessive LFO click bleed. No one has been able to isolate the problem, but it is probably related to poor grounding and poor connections between control and main boards...which is why it's an "intermittent" problem that only affects some builds.

Hope that helps.
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Re: Soma - LYRA-8 DIY Kit

Post by HenryBurlingame » Tue Feb 23, 2021 8:32 pm

Thanks so much flounderguts, very helpful!
FS: JMT SRV-1 Spring Reverb: viewtopic.php?f=74&t=238432

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