Has anyone put speakers inside of their Kosmo synth? I was thinking it might be cool to have an all in one unit. Curious if anyone has gone down this road!
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I am thinking about a speaker module too. I have no clue about “the thec” but there might be problems with speaker coils and neighbouring modules??? Surely some of the senoir members with more XP can enlighten us
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I guess I’m thinking more of a speaker box instead of an actual module. Maybe a box that’s the same width as my Kosmo that sits on the top and blends in really well. The module idea is really cool though, I’d love to see one of those!
@heckseven built one of these, but I’m not finding documentation in the forums from my phone. I often get inspiration from his kosmo page here: Kosmo - heckseven
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@Stef has a TDA2030 amplifier module . I also tried my luck with the same idea but could not get it to work on stripboard, waiting for a PCB now to give it another try!
Yes, I have a small TDA2030 amp module, but I will not include this as “normal” module in my rack, but I will create a 3D printed external Box with the speakers included. I would not recommend to include this in the rack, because the amp will get hot and needs a big heatsink, and especially in a closed rack I think this will disturb all the temperature sensitive modules like VCO’s etc. And of course in an external box you will have more space for bigger speakers.
My version runs with the power from an old 19V/3A notebook power supply, so the only connection you need is the audio out - e.g. from my Moritz Klein Output module - to the amp.
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My first MFOS Ultimate/Expander has an amp and speakers in its free-form cabinet. Don’t worry too much about inducing hum–at least not to the extent that it stops you from building. I used a modular Amazn stereo amplifier and two car speakers (circular with grilles). I really like being able to have the thing make the sound sometimes. Naturally, though, I prefer the full range and thudding bottom of a properly tuned speaker cabinet or two.
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My case has a 10cm middle row for two speakers, a power supply voltage display with on/off button, a amall amplifier for the speakers and headphones out. The plan is to add a clock module, a noise module, and multiple/attenuator module in the middle row.
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Yeah. I got a broken little marshall belt amp thing, fixed it (just needed a new power socket IIRC), and REALLY bodged it. Then, I took some rescued speakers from a broken old yamaha thing I got at a garage sale to circuit bend and hooked em up. It is not stereo, is super noisy, and is super fun to play with on occasion. Not sure I would go with that if you want some good-sounding speakers.
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I started with a little clacktronics clone (ill see if i can find the schem i made)
i have built and verified this one, dont know if i updated it.
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Looks good! Be aware, though, that the LM386 is not supposed to drive speakers less than 8Ω.
The TI LM386 datasheet shows applications with load impedances 4 Ω to 32 Ω.
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Thanks for the correction! I was positive that it could not drive a 4Ω speaker, so I went for the TDA2030 (which has other advantages as well). I have a few of them, so I will probably give it a try!
It ran fine while I used it =D if it goes bad… blame clackrltronics, that’s where I got the schem from haha
I am looking for a simple amp that runs on +/-12V, but I haven’t done any serious attempts to find one. However, the amp would go just onto the output module with speakers attached to the cabinet externally.
For the amp, I would go for a classD as they nowadays sounds pretty decent, can deliver a lot of POW! at small voltage/ampage.
For speakers I have some 3" full range drivers.
But this is still far away as I must paint the cabinet and test, trim, adjust and install the modules (this will be pretty permanent).
I was actually thinking of getting a 25(ish) watt guitar practice amp, disassembling it, and mounting it in a Kosmo sized case! We’ll see how it works out 
I got a small Orange 20w amp to mount in my Kosmo. The amp has 1 8ohm speaker in it, but I would like to add another without losing volume. Should I get 2 4ohm speakers? 2 16ohm speakers? Any help is appreciated!
Not an expert here, but as far as I know, it depends on whether you connect the speakers in parallel or in series.
In series: 2 x 8Ω speakers = 16Ω
In parallel: 2 x 8Ω speakers = 4Ω
In any case, you should make sure that the load of the speakers does not go beyond what the amplifier can deliver. In your case, you can stick on the 8Ω total load to be on the safe side and decide how to go about it (although the amp should mention somewhere whether you can use speakers with different loads, as you can typically do with guitar amplifiers).
I am not sure what you will gain anything from the added speaker though. The amplifier is mono, so you won’t get stereo just by that second speaker. Moreover, I don’t think you can get noticeably higher volumes as you will be driving both speakers with the same amplifier. The amplifier just gives what it can in terms of output, regardless of the number of speakers, considering that you will be keeping the load constant.
My hunch is, it’s not worth the hassle, just keep the amplifier with the speaker as is, but I might be wrong of course…
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My idea was to disassemble the amplifier and mount it in a Kosmo panel, and have one speaker on each side of the amplifier module for a more “even” sound and look, although still mono. The amp is only 20w, but it should be plenty loud for home use!