[sdiy] Re: bit one/DAC fault tip

[Stephen Lenham]

Hi Ruud, 

A simple way to test for a DAC fault - using only your ears - is to choose a 
voltage-controlled parameter, e.g. filter cutoff frequency, then slowly wind 
that parameter from minimum to maximum while holding down a sustained note. 
If you hear a smooth filter sweep then the DAC is _probably_ OK, but if 
there are any "jumps" in the cutoff frequency then it indicates a problem. 

Did you say that there were problems with the tuning? The A-Z of Analogue 
says that the Bit01 uses DCOs which - by definition - aren't under the 
control of the DAC, so any pitch problems might indicate that the fault is 
elsewhere. It's still worth checking the DAC though, just to rule it out. 

Cheers, 

Steve L. 

Rude 66 writes: 

> 
> stephen, 
> 
>  thanks for the tip. all my cleaning didn't help, so next suspects are the
> 4051 or the power supply. 
> 
> how does one measure this problem? oscilloscope? 
> 
> thanks! 
> 
> ruud 
>