Doepfer

Hi,
as sayed in the title i like to calibrate my A-185-2 precission adder.
It is not exactly 1V and not all Voltage adders are exactly 1V.
( no, this is no critsm )


I must calibrate my VCOs and i like to have the precision adder as a
reference.
I see there are only two trimmers.
some explanations would be appreciated.
thanks

my A-185-2 has a difference of 2cents ( tonal) between the different
switches.
this seems to be too mutch for me to name it "precision" Adder.
I hoped that i can trim this difference away.

when i think that 1 Volt is divided by 12 to get semitones,
2 cents (of a Semitone) is not much in Volts.
I think this 0,1% matching is then not enough.

The Module is _very_ useful for me.
Matching to 0,01% and paying finally a littlebit more would be the
better Deal at the end,
IMHO.


thanks
H.


--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > Hi,
> > as sayed in the title i like to calibrate my A-185-2 precission adder.
> > It is not exactly 1V and not all Voltage adders are exactly 1V.
> > ( no, this is no critsm )
> >
> > I must calibrate my VCOs and i like to have the precision adder as a
> > reference.
> > I see there are only two trimmers.
> > some explanations would be appreciated.
> > thanks
> 
> P2 on top right edge of the pcb is used to adjust the 1V coming from the
> switches if nothing is connected to the sockets.
> P1 in the lower section of the pcb is used to adjust the overall
> amplification. There is no trimming potentiometers for each inputs
as the

> resistors in the input stages are manually selected to 0.1% by our
> manufacturer. Consequently the difference between the different inputs
> should be less than 0.1%.
> 
> Best wishes
> Dieter Doepfer
>

> Hi,
> as sayed in the title i like to calibrate my A-185-2 precission adder.
> It is not exactly 1V and not all Voltage adders are exactly 1V.
> ( no, this is no critsm )
>
> I must calibrate my VCOs and i like to have the precision adder as a
> reference.
> I see there are only two trimmers.
> some explanations would be appreciated.
> thanks

P2 on top right edge of the pcb is used to adjust the 1V coming from the
switches if nothing is connected to the sockets.
P1 in the lower section of the pcb is used to adjust the overall
amplification. There is no trimming potentiometers for each inputs as the
resistors in the input stages are manually selected to 0.1% by our
manufacturer. Consequently the difference between the different inputs
should be less than 0.1%.

Best wishes
Dieter Doepfer

> The Module is _very_ useful for me.
> Matching to 0,01% and paying finally a littlebit more would be the
> better Deal at the end,
> IMHO.
>
> thanks
> H.

It would be possible to equip the module with 100k/0,01% mathing resistors
but this would increase the price clearly. The price for an 100k/0,01%
resistor is about Euro 12 for each resistor (e.g.
http://www.buerklin.com/gruppen/KapE/E072800.asp#m, order no. 35E330). In
the A-185-2 eight of these resistors are required which would increase the
price of the module by at least 100 Euro.

If desired we can order 100k/0.01% resistors and replace the 0.1% types by
the 0.01% types.

Best wishes
Dieter Doepfer

Speaking of being *very* useful, what is this thing exactly? Just a 
precise mixer intended for CV? What is the main application? Adding 
pitch modulation to a keyboard CV?

Thanks,
Doug


--- In Doepfer_a100@yahoogroups.com, "hemi_ch" 
<modulardudeldidum1@...> wrote:
>
> my A-185-2 has a difference of 2cents ( tonal) between the 
different
> switches.
> this seems to be too mutch for me to name it "precision" Adder.
> I hoped that i can trim this difference away.
> 
> when i think that 1 Volt is divided by 12 to get semitones,
> 2 cents (of a Semitone) is not much in Volts.
> I think this 0,1% matching is then not enough.
> 
> The Module is _very_ useful for me.
> Matching to 0,01% and paying finally a littlebit more would be the
> better Deal at the end,
> IMHO.
> 
> 
> thanks
> H.
> 
> 
> --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> >
> > > Hi,
> > > as sayed in the title i like to calibrate my A-185-2 
precission adder.
> > > It is not exactly 1V and not all Voltage adders are exactly 1V.
> > > ( no, this is no critsm )
> > >
> > > I must calibrate my VCOs and i like to have the precision 
adder as a
> > > reference.
> > > I see there are only two trimmers.
> > > some explanations would be appreciated.
> > > thanks
> > 
> > P2 on top right edge of the pcb is used to adjust the 1V coming 
from the
> > switches if nothing is connected to the sockets.
> > P1 in the lower section of the pcb is used to adjust the overall
> > amplification. There is no trimming potentiometers for each 
inputs
> as the
> > resistors in the input stages are manually selected to 0.1% by 
our
> > manufacturer. Consequently the difference between the different 
inputs

> > should be less than 0.1%.
> > 
> > Best wishes
> > Dieter Doepfer
> >
>

> Speaking of being *very* useful, what is this thing exactly? Just a
> precise mixer intended for CV? What is the main application? Adding
> pitch modulation to a keyboard CV?
>
> Thanks,
> Doug

The main application is to generate a common (and buffered) control voltage
that is used to control several VCOs with the same CV e.g. via the internal
CV bus. If you want to control e.g. three or four VCOs with a sequencer CV
plus keyboard CV (e.g. for transposition of the sequence), add a little bit
of modulation and/or pitch bend you need a adder that generates one common
CV for all VCOs. For each of the voltages a switch is available to turn the
CV in question on/off/inverted. In addition the module can be used as an
octave switch for all VCOs connected to the bus.

Best wishes
Dieter Doepfer

ou shit, i was not aware that those 0,01% Resistors are so expensive.
Ok, for Manufacturing it would not be a choice.
I can solder, but have often problems when desoldering.
For myself i could match some 0,1% Rssistors to 0,01% i think
what temperature is the best to desolder Doepfer Boards ?
a) the old ones
B) the newer ROHS Boards


thanks
H.


--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > The Module is _very_ useful for me.
> > Matching to 0,01% and paying finally a littlebit more would be the
> > better Deal at the end,
> > IMHO.
> >
> > thanks
> > H.
> 
> It would be possible to equip the module with 100k/0,01% mathing
resistors
> but this would increase the price clearly. The price for an 100k/0,01%
> resistor is about Euro 12 for each resistor (e.g.
> http://www.buerklin.com/gruppen/KapE/E072800.asp#m, order no.
35E330). In
> the A-185-2 eight of these resistors are required which would
increase the
> price of the module by at least 100 Euro.
> 
> If desired we can order 100k/0.01% resistors and replace the 0.1%
types by

> the 0.01% types.
> 
> Best wishes
> Dieter Doepfer
>

>>Speaking of being *very* useful, what is this thing exactly?<<
I patch my 1V/Okt signal(s) to it.
those are coming mostly from a Seqeunzer.
Basically i have just one Sequenzer patched to it to the first input.
With the related switch i can switch the sequenze between minus and plus.
this gives me a first possibility to "play" with my groove.
then i can add with the switches 1Volts and shifting the SEquenz up
and down this way.
In combination with other Knob and Switch tweakings this is a nice way
to "play" with my grooves.

since having more then one Sequenzer i sometimes patch both Sequenzers
to the a-185.
so i can mix them together in many Ways.
hmmmm......Yes i use it as a precise mixer. 
You're right ;)

I got this way really nice grooves.
another thing is that the a-185-2 works also as a Buffer.
Not unimportant when you use to patch 1V/okt signals over multiples to
many destinations as i do allways do.

Now ilike to have a second one or maybe two more.
i thought when use it to patch FM it might be good to have the Voltage
Adding very precise.

Regards,
H.


--- In Doepfer_a100@yahoogroups.com, "Doug" <dougc356@...> wrote:

>
> Speaking of being *very* useful, what is this thing exactly? Just a 
> precise mixer intended for CV? What is the main application? Adding 
> pitch modulation to a keyboard CV?
> 
> Thanks,
> Doug
> 
> 
> --- In Doepfer_a100@yahoogroups.com, "hemi_ch" 
> <modulardudeldidum1@> wrote:
> >
> > my A-185-2 has a difference of 2cents ( tonal) between the 
> different
> > switches.
> > this seems to be too mutch for me to name it "precision" Adder.
> > I hoped that i can trim this difference away.
> > 
> > when i think that 1 Volt is divided by 12 to get semitones,
> > 2 cents (of a Semitone) is not much in Volts.
> > I think this 0,1% matching is then not enough.
> > 
> > The Module is _very_ useful for me.
> > Matching to 0,01% and paying finally a littlebit more would be the
> > better Deal at the end,
> > IMHO.
> > 
> > 
> > thanks
> > H.
> > 
> > 
> > --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> > >
> > > > Hi,
> > > > as sayed in the title i like to calibrate my A-185-2 
> precission adder.
> > > > It is not exactly 1V and not all Voltage adders are exactly 1V.
> > > > ( no, this is no critsm )
> > > >
> > > > I must calibrate my VCOs and i like to have the precision 
> adder as a
> > > > reference.
> > > > I see there are only two trimmers.
> > > > some explanations would be appreciated.
> > > > thanks
> > > 
> > > P2 on top right edge of the pcb is used to adjust the 1V coming 
> from the
> > > switches if nothing is connected to the sockets.
> > > P1 in the lower section of the pcb is used to adjust the overall
> > > amplification. There is no trimming potentiometers for each 
> inputs
> > as the
> > > resistors in the input stages are manually selected to 0.1% by 
> our
> > > manufacturer. Consequently the difference between the different 
> inputs
> > > should be less than 0.1%.
> > > 
> > > Best wishes
> > > Dieter Doepfer
> > >
> >
>

> ou shit, i was not aware that those 0,01% Resistors are so expensive.
> Ok, for Manufacturing it would not be a choice.
> I can solder, but have often problems when desoldering.

With a solder wick it's very easy (for single sided pcbs only). For double
sided pcb's you need a special tool (desoldering station) but even with such
a tool desoldering can be a problem for double sided pcb's. Fortunately most
of the A-100 modules are single sided.

> For myself i could match some 0,1% Rssistors to 0,01% i think
> what temperature is the best to desolder Doepfer Boards ?
> a) the old ones
I think it was 370 degrees Celcius

> B) the newer ROHS Boards
we use 425 degrees Celcius (Weller solder tips code "8")

Best wishes
Dieter Doepfer