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Circuitbenders Forum => Drum machines => Circuitbending discussion => circuitbenders.co.uk CB55 - DIY Boss DR55. => Topic started by: geklimper on January 11, 2019, 04:21:14 PM

Title: Mix output extrem weak, individual outs normal
Post by: geklimper on January 11, 2019, 04:21:14 PM

Hi, just finished the CB55 build with two individual outputs for bassdrum and rim. All triggers are working, all the individual outputs are working too. But I have only a very very low output from the mix. Caps, diodes and transistors are in the right direction, everything seems ok. I don't know where to look, so any hint is much appreciated.

Title: Re: Mix output extrem weak, individual outs normal
Post by: sirgavalot on January 13, 2019, 05:31:57 PM

Have you got an audio probe? The main instrument lines join before R73 before the accent circuit. Using a probe and the schematic (below) you can follow the signal from where it's full volume to where the volume is reduced and get a better idea as to where the source of your problem is. If you look at the schematic there's still quite a number of components between the individual outputs and the main mix output

http://www.mediafire.com/view/tzl34mlfqf6ii1l/CB55-schematic.png

Title: Re: Mix output extrem weak, individual outs normal
Post by: geklimper on January 13, 2019, 06:20:46 PM

Thanks for the schematic. It's not that I can "read" it, but I will try my best to find the problem point.

Title: [SOLVED] Re: Mix output extrem weak, individual outs normal
Post by: geklimper on January 14, 2019, 11:35:49 AM

Found the culprit: I missed soldering one resistor leg in the output circuit. I was looking over the board multiple times, didn't see it. Thanks agein, sirgavalot - I got lost in the schematic (I'm a complete noob regarding the working of electronic circuits), but it brought me to examine the board once more.
And now: playing with this nice drum machine.