Doepfer

>
> Ever since I own an A-121, I suspected, that its output is quite low
> in comparison to the plain oscillator output level. Yesterday I made a
> comparison between the A-121 and the A-105, that I received recently.
> I routed a sawtooth from the A-111 to both of their inputs. I tweaked
> the Input attenuator of both filters so, that the levels are just at
> the point before the input signals are distorted by the filter. The
> filters were both fully opened without any modulation or resonance. I
> normalled the A-105 output to 0db deviation from line level in my
> little mixer and then checked the output level of the A-121, which
> seemed to be around 20db lower in output. Is this the normal behaviour
> of this filter?
> 
> Thank you for any assistance in this,
> -Michael
>

>
> Hello,
> 
> I've noticed this too about the A-121.  There is information elsewhere about modifying an A-120 for increased input gain; would it be straightforward to modify the A-121 to get more gain as well?
> 
> Has anyone done this?
> 
> Ernst
> 
> 
> --- In Doepfer_a100@yahoogroups.com, "Michael Wagner" <michael.wgnr@> wrote:
> >
> > Ever since I own an A-121, I suspected, that its output is quite low
> > in comparison to the plain oscillator output level. Yesterday I made a
> > comparison between the A-121 and the A-105, that I received recently.
> > I routed a sawtooth from the A-111 to both of their inputs. I tweaked
> > the Input attenuator of both filters so, that the levels are just at
> > the point before the input signals are distorted by the filter. The
> > filters were both fully opened without any modulation or resonance. I
> > normalled the A-105 output to 0db deviation from line level in my
> > little mixer and then checked the output level of the A-121, which
> > seemed to be around 20db lower in output. Is this the normal behaviour
> > of this filter?
> > 
> > Thank you for any assistance in this,
> > -Michael
> >
>

>
> Okay, I see this on the Doepfer DIY page:
> 
> "Especially for the first A-100 VCFs and VCAs (A-120, A-121, A-122 and first versions of A-130, A-131) the audio inputs have been designed to avoid distortion with standard A-100 signals (e.g. VCO). Lowering the input resistors will allow distortion for these moduls too."
> 
> So can I solder a 100k-Ohm resister in parallel with the input resistor to boost the input level?  More crucially for me as someone who can't read a circuit board, which one would that be?
> 
> thanks!
> Ernst
> 
> 
> --- In Doepfer_a100@yahoogroups.com, "E Karel" <eklkrl@> wrote:
> >
> > Hello,
> > 
> > I've noticed this too about the A-121.  There is information elsewhere about modifying an A-120 for increased input gain; would it be straightforward to modify the A-121 to get more gain as well?
> > 
> > Has anyone done this?
> > 
> > Ernst
> > 
> > 
> > --- In Doepfer_a100@yahoogroups.com, "Michael Wagner" <michael.wgnr@> wrote:
> > >
> > > Ever since I own an A-121, I suspected, that its output is quite low
> > > in comparison to the plain oscillator output level. Yesterday I made a
> > > comparison between the A-121 and the A-105, that I received recently.
> > > I routed a sawtooth from the A-111 to both of their inputs. I tweaked
> > > the Input attenuator of both filters so, that the levels are just at
> > > the point before the input signals are distorted by the filter. The
> > > filters were both fully opened without any modulation or resonance. I
> > > normalled the A-105 output to 0db deviation from line level in my
> > > little mixer and then checked the output level of the A-121, which
> > > seemed to be around 20db lower in output. Is this the normal behaviour
> > > of this filter?
> > > 
> > > Thank you for any assistance in this,
> > > -Michael
> > >
> >
>

>
> Hey, based on this -- http://www.analoguehaven.com/usercomm/diy/#a120 -- I took a guess as to which resistor seemed closest to the input, soldered the resistor on the back of the board, and it worked!  Much more power to this module now.  Now to modify my A-120....
> 
>