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A-121 Multimode Filter behaviour

2002-04-03 by mdimmm

Dear list members,

I was under the impression that a high pass filter should let a 
signal pass almost unchanged with the cut-off frequency all the 
way down (the opposite of a low pass). However my A-121 
seems to be cutting higher frequencies at low cut-off settings 
(resonance all the way down), more like a band pass filter.
The result is especially clear when runnig a rich external signal 
through it, songs on the radio in my case.

When viewing an A-121's sine wave output on an oscilloscope, 
the "Band" output seems to be the only output to generate a true 
sine wave. The waveforms from "High" and "Low" seem to be 
clipped at the highest and lowest points, respectively, and the 
"Notch" output is significantly lower than the others. 
Is this an anomaly of my module or do all A-121's behave like 
this?


And which of the 4 lengths of cables available for the A-100 are 
the white ones?

Thanks
M. Dimm

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