Doepfer

Today I noticed a strange behavior in my Dark Energy I. I noticed a constant modulation of the cutoff frequency. It sounds like the cutoff is being modulated by an audio-rate square wave. Of course I ruled out any bleed by whatever internal CV sources are available. The modulation won't go away.

Maybe the CEM3394 has turned bad? If so, I have a Simmons SDS-800 which I don't use which has 4x CEM3394 chips inside. Is there anything I have to consider when swapping the chip myself (apart from the obvious need to re-calibrate various parameters in the Dark Energy)?

kind regards

Frank

> Today I noticed a strange behavior in my Dark Energy I. I noticed a constant modulation of the cutoff frequency. It 
> sounds like the cutoff is being modulated by an audio-rate square wave. Of course I ruled out any bleed by whatever 
> internal CV sources are available. The  modulation won't go away.
> Maybe the CEM3394 has turned bad? If so, I have a Simmons SDS-800 which I don't use which has 4x CEM3394 chips inside. Is 
> there anything I have to consider when swapping the chip myself (apart from the obvious need to re-calibrate various 
> parameters in the Dark Energy)?
> 
> 
> kind regards
> Frank

If it's a faulty CEM3394 replacing the circuit should fix the problem.

Best wishes
Dieter Doepfer

> Thanks Mr. Doepfer!
> 
> 
> Since I will have to remove the Supply/Interface Board to reach the DE's CEM3394, I assume I have to remove the 3.5mm 
> jack screws on the top of the casing? What's the proper tool to do so? 
> 
> 
> thanks so much and kind regards
> Frank

You need a suitable socket wrench (about 11 mm). Even pliers may be used but this increases the risk to damage the case and nuts.

Best wishes
Dieter Doepfer

Am 18.02.2015 um 09:50 schrieb yahoo@doepfer.de [Doepfer_a100]:
>> assume I have to remove the 3.5mm
>> jack screws on the top of the casing? What's the proper tool to do so?
>>
> You need a suitable socket wrench (about 11 mm). Even pliers may be used but this increases the risk to damage the case and nuts.
>
Hello Frank

If you don't have a wrench set, then you may use a universal  plier with 
a protecting adhesive tape like seen here:
http://fa.utfs.org/diy/monopoly_mirage/images/100-0055_IMG.jpg

Florian

> assume I have to remove the 3.5mm
> jack screws on the top of the casing? What's the proper tool to do so?

The hex nuts?  Nina made a tool just for that if anyone's interested: https://twitter.com/nr2097/status/565815987178831872  You can 3D print that to get a handy little device to screw in hex nuts with, without scratching the faceplate.

All the best,
Zoë.