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Hack to safely disable VCO for ext audio (resolved)

PostPosted: Thu Sep 07, 2017 11:03 pm
by part12studios
Hi there,

I just got this sucker and I love it! As an owner of a MiniBrute and MicroBrute I was really wanting to know if i'd be able to actually tell a difference and I really do! Just feels warmer.

So I got a MCV4 running to it able to control LFO Trigger Pitch and Filter. So the final test was external audio in.. and i got it working.. turning off envelope and I hear sound going through, but I also still hear the OSC.

Is there a way to kill the OSC while using external audio in? I really want to use the filter, but its pretty much useless if I can't mute the internal OSC in most cases (running a live instrument or drum beat through it)


I have done some research since posting this and I understand now this is by design and not something that can be disabled. Does anyone know if there is an official tutorial on how it could be done? I would definitely like to keep this device, but it really does feel like allowing the VCO to be muted would be great.

That said, I saw some talk in another thread about doing some kind of solution but i wonder.. would it be hard to put a switch in to simply kill the VCO? That would seem like something fairly straight forward? I'm not an electrician though so I'd rather hear from the pros.

Alternately, what if it could be that when the Pot for the Frequency is at 0% it kills it? I just say that because maybe that's easier and would remove the need to add a hole / switch to the mix.

Thanks!
Caleb

Re: Hack to safe disable VCO to allow Audio IN to be clean?

PostPosted: Tue Sep 19, 2017 11:36 pm
by part12studios
bump.

Without meaning to oversimplify something I'm not confident in, it seems like this would be something pretty easy to do? maybe there is a way to mute or bypass the VCO?

It would just be super helpful to get a few pointers on how this could be achieved. I have a local electronic repair person I want to hire to do the work (as I'm not trusting myself with a soldering iron on something like this) but I just want to be sure I give him good instructions so he can do the work efficiently and most importantly, correctly.


Thanks
Caleb

Re: Hack to safe disable VCO to allow Audio IN to be clean?

PostPosted: Fri Oct 13, 2017 9:43 am
by part12studios
bump

With all the mods out there it seems like this would be an obvious one. That said that's what makes me concerned that it's not so easily done because who wants their external audio in to be competing with the VCO? However maybe how it's structured makes it impossible or dangerous to bypass the VCO?

Re: Hack to safely disable VCO to allow Audio IN to be clean

PostPosted: Tue Nov 28, 2017 4:55 pm
by Raspy
Hi,
It should be easy. Just cut JMP57 and you will get silent. It’s a connection point between VCO and VCF.

Re: Hack to safely disable VCO to allow Audio IN to be clean

PostPosted: Tue Nov 28, 2017 5:04 pm
by part12studios
yes that turned out to be the case. I got some help from the vintage synth folks a few weeks ago.

i made a video demoing it

https://www.youtube.com/watch?v=U2B-XVav4o0

yes jumper 57 did the trick.. super nice!

Thanks!
Caleb