Doepfer

Hello,

The output level of my new A-188-1 4096 stages is a bit low, espesialy
when the mix is in 5/5.

Is this normal?
Can this be ajusted?

Thanks in advance.

Greetings Dirk.

phase problem internally? just guessing....

vliesgaard <vliesgaard@yahoo.com> wrote:          Hello,

The output level of my new A-188-1 4096 stages is a bit low, espesialy
when the mix is in 5/5.

Is this normal?
Can this be ajusted?

Thanks in advance.

Greetings Dirk.



         


[Non-text portions of this message have been removed]

If it's a phase problem then it should also get louder when I turn the
delay clock knob, that does not happen, it stay's annoyingly low.

Help.

Best Dirk.

--- In Doepfer_a100@yahoogroups.com, Ross Goniakowski <carfull@...> wrote:

>
>  phase problem internally? just guessing....
> 
> vliesgaard <vliesgaard@...> wrote:          Hello,
> 
> The output level of my new A-188-1 4096 stages is a bit low, espesialy
> when the mix is in 5/5.
> 
> Is this normal?
> Can this be ajusted?
> 
> Thanks in advance.
> 
> Greetings Dirk.
> 
> 
> 
>          
> 
> 
> [Non-text portions of this message have been removed]
>

hello dirk,

on the very first prototypes of the module the output level was
a bit low, so on the production models the output level was
increased. maybe the final amplifier in your module has a
problem. how does your a188/1 loudness compare to the
loudness of a filter?

best wishes

ingo




--- In Doepfer_a100@yahoogroups.com, "vliesgaard" <vliesgaard@...> 
wrote:
>
> If it's a phase problem then it should also get louder when I turn 
the
> delay clock knob, that does not happen, it stay's annoyingly low.
> 
> Help.
> 
> Best Dirk.
> 
> --- In Doepfer_a100@yahoogroups.com, Ross Goniakowski <carfull@> 
wrote:
> >
> >  phase problem internally? just guessing....
> > 
> > vliesgaard <vliesgaard@> wrote:          Hello,
> > 
> > The output level of my new A-188-1 4096 stages is a bit low, 
espesialy

> > when the mix is in 5/5.
> > 
> > Is this normal?
> > Can this be ajusted?
> > 
> > Thanks in advance.
> > 
> > Greetings Dirk.
> > 
> > 
> > 
> >          
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
>

Hello members and Ingo,

These are the knob postions:
All switches +
Delayclock 10
CV2 0
Audio input 10
Feedback 0
Mix Orig
Only Patchcords in audio in and mix out.
A-110 pulse as source.

First thing I notice is that the mix out output is inverted and a bit
reduced in level, about 80% on a linear mixer. 
Then when you turn the mix knob, the sound level drops. At 3/7 it has
reached its minimum of -10dB compared to the Orig position. At BBD it
has gone up again to -5dB. (I used the VU meter on my mixing desk for
this measurement.)

Other than that is seems to work as it should.
But the level drop is pretty annoying. And I can't imagine that it is
designed this way.

Any sugestions?

By Dirk.

--- In Doepfer_a100@yahoogroups.com, "selfoscillate"
<synaptic_music@...> wrote:

>
> 
> hello dirk,
> 
> on the very first prototypes of the module the output level was
> a bit low, so on the production models the output level was
> increased. maybe the final amplifier in your module has a
> problem. how does your a188/1 loudness compare to the
> loudness of a filter?
> 
> best wishes
> 
> ingo
> 
> 
> 
> 
> --- In Doepfer_a100@yahoogroups.com, "vliesgaard" <vliesgaard@> 
> wrote:
> >
> > If it's a phase problem then it should also get louder when I turn 
> the
> > delay clock knob, that does not happen, it stay's annoyingly low.
> > 
> > Help.
> > 
> > Best Dirk.
> > 
> > --- In Doepfer_a100@yahoogroups.com, Ross Goniakowski <carfull@> 
> wrote:
> > >
> > >  phase problem internally? just guessing....
> > > 
> > > vliesgaard <vliesgaard@> wrote:          Hello,
> > > 
> > > The output level of my new A-188-1 4096 stages is a bit low, 
> espesialy
> > > when the mix is in 5/5.
> > > 
> > > Is this normal?
> > > Can this be ajusted?
> > > 
> > > Thanks in advance.
> > > 
> > > Greetings Dirk.
> > > 
> > > 
> > > 
> > >          
> > > 
> > > 
> > > [Non-text portions of this message have been removed]
> > >
> >
>

hello dirk,

well, i'm not sure, but after reading your answer
i think some of this could be normal behaviour.
the dry/wet control is a linear crossfade and not
an "equal power" crossfade, so you have a level drop
at the center position, this is normal. the bbd output
is not of the same loudness than the input signal
(or dry signal), but that is also normal. almost all
modules alter the loudness in some ways.
thats why i suggested that you compare the level of
your bbd module with the output of a filter (which
usually alters the signal loudness too).

strange is that the lowest level on your bbd
is not when the mix knob is in center position,
and that the output is inverted.

dieter, maybe you can chime in and help us?

best wishes

ingo



--- In Doepfer_a100@yahoogroups.com, "vliesgaard" <vliesgaard@...> 
wrote:
>
> Hello members and Ingo,
> 
> These are the knob postions:
> All switches +
> Delayclock 10
> CV2 0
> Audio input 10
> Feedback 0
> Mix Orig
> Only Patchcords in audio in and mix out.
> A-110 pulse as source.
> 
> First thing I notice is that the mix out output is inverted and a 
bit
> reduced in level, about 80% on a linear mixer. 
> Then when you turn the mix knob, the sound level drops. At 3/7 it 
has
> reached its minimum of -10dB compared to the Orig position. At BBD 
it
> has gone up again to -5dB. (I used the VU meter on my mixing desk 
for
> this measurement.)
> 
> Other than that is seems to work as it should.
> But the level drop is pretty annoying. And I can't imagine that it 
is
> designed this way.
> 
> Any sugestions?
> 
> By Dirk.
> 
> --- In Doepfer_a100@yahoogroups.com, "selfoscillate"
> <synaptic_music@> wrote:
> >
> > 
> > hello dirk,
> > 
> > on the very first prototypes of the module the output level was
> > a bit low, so on the production models the output level was
> > increased. maybe the final amplifier in your module has a
> > problem. how does your a188/1 loudness compare to the
> > loudness of a filter?
> > 
> > best wishes
> > 
> > ingo
> > 
> > 
> > 
> > 
> > --- In Doepfer_a100@yahoogroups.com, "vliesgaard" <vliesgaard@> 
> > wrote:
> > >
> > > If it's a phase problem then it should also get louder when I 
turn 
> > the
> > > delay clock knob, that does not happen, it stay's annoyingly 
low.
> > > 
> > > Help.
> > > 
> > > Best Dirk.
> > > 
> > > --- In Doepfer_a100@yahoogroups.com, Ross Goniakowski 
<carfull@> 

> > wrote:
> > > >
> > > >  phase problem internally? just guessing....
> > > > 
> > > > vliesgaard <vliesgaard@> wrote:          Hello,
> > > > 
> > > > The output level of my new A-188-1 4096 stages is a bit low, 
> > espesialy
> > > > when the mix is in 5/5.
> > > > 
> > > > Is this normal?
> > > > Can this be ajusted?
> > > > 
> > > > Thanks in advance.
> > > > 
> > > > Greetings Dirk.
> > > > 
> > > > 
> > > > 
> > > >          
> > > > 
> > > > 
> > > > [Non-text portions of this message have been removed]
> > > >
> > >
> >
>

> hello dirk,
>
> well, i'm not sure, but after reading your answer
> i think some of this could be normal behaviour.
> the dry/wet control is a linear crossfade and not
> an "equal power" crossfade, so you have a level drop
> at the center position, this is normal. the bbd output
> is not of the same loudness than the input signal
> (or dry signal), but that is also normal. almost all
> modules alter the loudness in some ways.
> thats why i suggested that you compare the level of
> your bbd module with the output of a filter (which
> usually alters the signal loudness too).
>
> strange is that the lowest level on your bbd
> is not when the mix knob is in center position,
> and that the output is inverted.
>
> dieter, maybe you can chime in and help us?

OK, here is my comment.

1. The output levels of the six different BBD circuits (128...4096
stages/MN3xxx) are a bit different. Consequently the A-188-1 modules with
different stages and circuits behave a bit different. Even BBD circuits with
the same number of stages but different circuit types (e.g. 256 stage BBD
circuits MN3009 and MN3209) are a bit different.

2. The output impedance of the A-188-1 is about 5k. It's because the mix
between the original and BBD signal is made with a linear 10k potentiometer
with the original signal on one terminal and the BBD signal on the other
terminal. The center terminal is the module output. Consequently in the
leftmost or rightmost position the signals (original or pure BBD) appear
without additional serial resistance as the potentiometer is at one of it's
end positions. In the center position the two signals are mixed via 5kOhm
each (10k/2 = 5k). This is why the level becomes a bit lower in the center
position. It depends upon the ouputload how much the level decreases. As
most A-100 modules have a 50k potentiometer at the audio input the level
drop will be about 10% (5k/50k). If the A-188-2 output is connected to a
load less than 50k the level drop may be more. We think about an additional
circuit on the board that compensates the level changes. But as the is no
more space on the pc board a complete redesign would be necessary.

3. The original signal appears indeed inverted at the output. But as the
module has a polarity switch for the BBD signal an additonal polarity switch
for the original signal would not add new features. It would have been
possible to plan a polarity switch for the original signal instead for the
BBD signal but the audible effect would be the same. I can't see any
application where the non-inverted original signal would be necessary.

Best wishes
Dieter Doepfer

Hello Ingo and Dieter,

The level drop in Org position is about the same as with the wasp
filters, so that would be normal.
I also think that the MN3005 would have the most level drop of all the
bbd's, since it has the most stages.

Thanks for the reply's.

By Dirk.



--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > hello dirk,
> >
> > well, i'm not sure, but after reading your answer
> > i think some of this could be normal behaviour.
> > the dry/wet control is a linear crossfade and not
> > an "equal power" crossfade, so you have a level drop
> > at the center position, this is normal. the bbd output
> > is not of the same loudness than the input signal
> > (or dry signal), but that is also normal. almost all
> > modules alter the loudness in some ways.
> > thats why i suggested that you compare the level of
> > your bbd module with the output of a filter (which
> > usually alters the signal loudness too).
> >
> > strange is that the lowest level on your bbd
> > is not when the mix knob is in center position,
> > and that the output is inverted.
> >
> > dieter, maybe you can chime in and help us?
> 
> OK, here is my comment.
> 
> 1. The output levels of the six different BBD circuits (128...4096
> stages/MN3xxx) are a bit different. Consequently the A-188-1 modules
with
> different stages and circuits behave a bit different. Even BBD
circuits with
> the same number of stages but different circuit types (e.g. 256
stage BBD
> circuits MN3009 and MN3209) are a bit different.
> 
> 2. The output impedance of the A-188-1 is about 5k. It's because the mix
> between the original and BBD signal is made with a linear 10k
potentiometer
> with the original signal on one terminal and the BBD signal on the other
> terminal. The center terminal is the module output. Consequently in the
> leftmost or rightmost position the signals (original or pure BBD) appear
> without additional serial resistance as the potentiometer is at one
of it's
> end positions. In the center position the two signals are mixed via
5kOhm
> each (10k/2 = 5k). This is why the level becomes a bit lower in the
center
> position. It depends upon the ouputload how much the level decreases. As
> most A-100 modules have a 50k potentiometer at the audio input the level
> drop will be about 10% (5k/50k). If the A-188-2 output is connected to a
> load less than 50k the level drop may be more. We think about an
additional
> circuit on the board that compensates the level changes. But as the
is no
> more space on the pc board a complete redesign would be necessary.
> 
> 3. The original signal appears indeed inverted at the output. But as the
> module has a polarity switch for the BBD signal an additonal
polarity switch
> for the original signal would not add new features. It would have been
> possible to plan a polarity switch for the original signal instead
for the

> BBD signal but the audible effect would be the same. I can't see any
> application where the non-inverted original signal would be necessary.
> 
> Best wishes
> Dieter Doepfer
>