Synth-DIY Yahoo! Groups Archives

Thread

A127 and the BOM

2015-09-19 by achtung_999

Tomorrow I am picking up a used A127 from someone that sells it for a nice price.

I am of course looking at the BOM module also..

One HUGE question remains though:

why are the LFO outputs left off the BOM module?

Seems like a pretty strange omission to me...

Ernst

AW: [Doepfer_a100] A127 and the BOM

2015-09-21 by yahoo@doepfer.de

> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

Re: [Doepfer_a100] A127 and the BOM

2015-09-21 by achtung_999

Oh that would be excellent! Thanks!

Ernst

Show quoted textHide quoted text

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-21 by achtung_999

btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:

Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by achtung_999

Found this from a discussion in 2009:

"The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of

the TL084. 1k protection resistors should be used to connect these pins to
the additional sockets. And a simple voltage divider made of two resistors
is recommended for the rectangle output because pin 8 outputs about +/-11V
(i.e. ~ 22V overall voltage level).

Best wishes
Dieter Doepfer"

Is this also valid for the version 2?

And about the mentioned voltage divider: what values do you advise for these?

all the best,

Ernst

Show quoted textHide quoted text

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:

btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by Nicholas Keller

http://www.raltron.com/cust/tools/voltage_divider.asp

Insert the input voltage of 22, value of R1 (numbers only, 1K = 1000), and desired output voltage of 5 (to match range of other Doepfer LFOs) or 10....and press compute.

Show quoted textHide quoted text

On Tuesday, September 22, 2015, achtung_999 heinrich.himmelwasser@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Found this from a discussion in 2009:

"The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
the TL084. 1k protection resistors should be used to connect these pins to
the additional sockets. And a simple voltage divider made of two resistors
is recommended for the rectangle output because pin 8 outputs about +/-11V
(i.e. ~ 22V overall voltage level).

Best wishes
Dieter Doepfer"

Is this also valid for the version 2?
And about the mentioned voltage divider: what values do you advise for these?

all the best,

Ernst

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by achtung_999

Thanks for that Nicholas! Most helpful!

Ernst

On Tue, Sep 22, 2015 at 11:45 AM, Nicholas Keller maq163x2@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

http://www.raltron.com/cust/tools/voltage_divider.asp

Insert the input voltage of 22, value of R1 (numbers only, 1K = 1000), and desired output voltage of 5 (to match range of other Doepfer LFOs) or 10....and press compute.

Show quoted textHide quoted text

On Tuesday, September 22, 2015, achtung_999 heinrich.himmelwasser@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Found this from a discussion in 2009:

"The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
the TL084. 1k protection resistors should be used to connect these pins to
the additional sockets. And a simple voltage divider made of two resistors
is recommended for the rectangle output because pin 8 outputs about +/-11V
(i.e. ~ 22V overall voltage level).

Best wishes
Dieter Doepfer"

Is this also valid for the version 2?
And about the mentioned voltage divider: what values do you advise for these?

all the best,

Ernst

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com>; wrote:
Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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RE: [Doepfer_a100] A127 and the BOM

2015-09-22 by Janne Gson Berg

Input voltage should be 11, not 22. +/- 11V should be transformed to +/- 5V.

/Janne

To: Doepfer_a100@yahoogroups.com
From: Doepfer_a100@yahoogroups.com
Date: Tue, 22 Sep 2015 12:19:03 +0200
Subject: Re: [Doepfer_a100] A127 and the BOM

Thanks for that Nicholas! Most helpful!

Ernst

On Tue, Sep 22, 2015 at 11:45 AM, Nicholas Keller maq163x2@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

http://www.raltron.com/cust/tools/voltage_divider.asp

Insert the input voltage of 22, value of R1 (numbers only, 1K = 1000), and desired output voltage of 5 (to match range of other Doepfer LFOs) or 10....and press compute.

Show quoted textHide quoted text

On Tuesday, September 22, 2015, achtung_999 heinrich.himmelwasser@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Found this from a discussion in 2009:

"The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
the TL084. 1k protection resistors should be used to connect these pins to
the additional sockets. And a simple voltage divider made of two resistors
is recommended for the rectangle output because pin 8 outputs about +/-11V
(i.e. ~ 22V overall voltage level).

Best wishes
Dieter Doepfer"

Is this also valid for the version 2?
And about the mentioned voltage divider: what values do you advise for these?

all the best,

Ernst

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <;heinrich.himmelwasser@gmail.com> wrote:
Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by achtung_999

Yes! Thank you Janne!

On Tue, Sep 22, 2015 at 12:57 PM, Janne Gson Berg tapirkillen@hotmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Input voltage should be 11, not 22. +/- 11V should be transformed to +/- 5V.

/Janne

To: Doepfer_a100@yahoogroups.com
From: Doepfer_a100@yahoogroups.com
Date: Tue, 22 Sep 2015 12:19:03 +0200
Subject: Re: [Doepfer_a100] A127 and the BOM

Thanks for that Nicholas! Most helpful!

Ernst

On Tue, Sep 22, 2015 at 11:45 AM, Nicholas Keller maq163x2@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

http://www.raltron.com/cust/tools/voltage_divider.asp

Insert the input voltage of 22, value of R1 (numbers only, 1K = 1000), and desired output voltage of 5 (to match range of other Doepfer LFOs) or 10....and press compute.

Show quoted textHide quoted text

On Tuesday, September 22, 2015, achtung_999 heinrich.himmelwasser@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Found this from a discussion in 2009:

"The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
the TL084. 1k protection resistors should be used to connect these pins to
the additional sockets. And a simple voltage divider made of two resistors
is recommended for the rectangle output because pin 8 outputs about +/-11V
(i.e. ~ 22V overall voltage level).

Best wishes
Dieter Doepfer";

Is this also valid for the version 2?
And about the mentioned voltage divider: what values do you advise for these?

all the best,

Ernst

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
btw. I have a version 2

On Mon, Sep 21, 2015 at 2:09 PM, achtung_999 <heinrich.himmelwasser@gmail.com> wrote:
Oh that would be excellent! Thanks!

Ernst

On Mon, Sep 21, 2015 at 10:59 AM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Tomorrow I am picking up a used A127 from someone that sells it for a nice price.
> I am of course looking at the BOM module also..
> One HUGE question remains though:
> why are the LFO outputs left off the BOM module?
> Seems like a pretty strange omission to me...
>
>
> Ernst

Of course the signals of the LFOs are available on the pc boards. But we would have to increase the width of the front panel to add
the LFO outputs. If you want to built your own breakout module I can tell you the corresponding solder points on the A-127 pcb.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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AW: [Doepfer_a100] A127 and the BOM

2015-09-22 by yahoo@doepfer.de

> Found this from a discussion in 2009:
>
>
> "The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
> the TL084. 1k protection resistors should be used to connect these pins to
> the additional sockets. And a simple voltage divider made of two resistors
> is recommended for the rectangle output because pin 8 outputs about +/-11V
> (i.e. ~ 22V overall voltage level).
>
> Best wishes
> Dieter Doepfer"
>
> Is this also valid for the version 2?
> And about the mentioned voltage divider: what values do you advise for these?

The circuitry around the LFO has not changed. So these notes are valid for all versions of the module.

The dimensioning of the voltage divider depends upon the desired attenuation of the rectangle signal. The load of the voltage
divider should be not less that ~ 5k. E.g. 3k+3k would half the level, 3k+1k would divide the level by 4. You may even use a 5k or
10k trimming potentiometer.

Best wishes
Dieter Doepfer

Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by achtung_999

Great thanks Dieter!

Ernst

On Tue, Sep 22, 2015 at 1:48 PM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

> Found this from a discussion in 2009:
>
>
> "The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
> the TL084. 1k protection resistors should be used to connect these pins to
> the additional sockets. And a simple voltage divider made of two resistors
> is recommended for the rectangle output because pin 8 outputs about +/-11V
> (i.e. ~ 22V overall voltage level).
>
> Best wishes
> Dieter Doepfer"
>
> Is this also valid for the version 2?
> And about the mentioned voltage divider: what values do you advise for these?

The circuitry around the LFO has not changed. So these notes are valid for all versions of the module.

The dimensioning of the voltage divider depends upon the desired attenuation of the rectangle signal. The load of the voltage
divider should be not less that ~ 5k. E.g. 3k+3k would half the level, 3k+1k would divide the level by 4. You may even use a 5k or
10k trimming potentiometer.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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Re: [Doepfer_a100] A127 and the BOM

2015-09-22 by Nicholas Keller

My numbers were to reduce the LFO output to the typical Doepfer LFO range,

which is -/+2.5V, not -/+5V.

So 22->5 was correct for that result.

Nick

Show quoted textHide quoted text

On Tuesday, September 22, 2015, achtung_999 heinrich.himmelwasser@gmail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Great thanks Dieter!

Ernst

On Tue, Sep 22, 2015 at 1:48 PM, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> Found this from a discussion in 2009:
>
>
> "The LFO outputs are available at pin 7 (triangle) and pin 8 (rectangle) of
> the TL084. 1k protection resistors should be used to connect these pins to
> the additional sockets. And a simple voltage divider made of two resistors
> is recommended for the rectangle output because pin 8 outputs about +/-11V
> (i.e. ~ 22V overall voltage level).
>
> Best wishes
> Dieter Doepfer"
>
> Is this also valid for the version 2?
> And about the mentioned voltage divider: what values do you advise for these?

The circuitry around the LFO has not changed. So these notes are valid for all versions of the module.

The dimensioning of the voltage divider depends upon the desired attenuation of the rectangle signal. The load of the voltage
divider should be not less that ~ 5k. E.g. 3k+3k would half the level, 3k+1k would divide the level by 4. You may even use a 5k or
10k trimming potentiometer.

Best wishes
Dieter Doepfer

------------------------------------

------------------------------------

------------------------------------

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