From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!
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oldcrow
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by oldcrow » Tue Jan 09, 2018 7:05 pm
Heya folks,
With the return of certain chips courtesy of Alfa Rpar and Erica Synths, I can now make the crOwBX-A voice card. As with the crOwBX cards, these will be drop-in compatible for vintage machines but also able to be used with my 8-voice backplane. Right now it is a work in progress, but I should have boards to test before CNY hits.
--Crow

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oldcrow
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by oldcrow » Tue Jan 09, 2018 7:07 pm
FYI yes I saw the Behringer UBXA thing. I'll believe it when I see it.

This project is about making cards that work in vintage machines and for the general DIY wanderlust.

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J3RK
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by J3RK » Tue Jan 09, 2018 7:24 pm
oldcrow wrote:FYI yes I saw the Behringer UBXA thing. I'll believe it when I see it.

This project is about making cards that work in vintage machines and for the general DIY wanderlust.


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wavydave
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by wavydave » Tue Jan 09, 2018 9:30 pm
Count me in!
I already have two 8-voice OB-Xas (one is apart though), and I would like to do comparisons.
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JanneI
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by JanneI » Wed Jan 10, 2018 3:52 am
Crow: So what are the actual differences between the original OB-X and OB-Xa voice cards? CEM3340 & CEM3320 instead of discrete components? Anything else?
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tobb
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by tobb » Wed Jan 10, 2018 6:07 am
(as drop-in for vintages it will be problematic due to the resonance of the AS3320!)
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oldcrow
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by oldcrow » Wed Jan 10, 2018 9:41 am
I will deal with that when I test the board. Changing the resonance control profile is not very hard for either filter.
tobb wrote:
(as drop-in for vintages it will be problematic due to the resonance of the AS3320!)
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The Real MC
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by The Real MC » Wed Jan 10, 2018 11:50 pm
oldcrow wrote:I will deal with that when I test the board. Changing the resonance control profile is not very hard for either filter.
tobb wrote:
(as drop-in for vintages it will be problematic due to the resonance of the AS3320!)
Just checked the schematics.
OBXa voicecard has some signals that are not TTL compatible thus it is not interchangeable with OBX.
I discovered this for the OBSX too. Telltale was the 7416 on the processor board.
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oldcrow
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by oldcrow » Thu Jan 11, 2018 12:05 am
Right, this card will have its own backplane, etc. It was not meant to work in a crowbx/OBX setup.
The Real MC wrote:oldcrow wrote:I will deal with that when I test the board. Changing the resonance control profile is not very hard for either filter.
Just checked the schematics.
OBXa voicecard has some signals that are not TTL compatible thus it is not interchangeable with OBX.
I discovered this for the OBSX too. Telltale was the 7416 on the processor board.