Dieter,

A while ago I asked you about the mod mentioned at the bottom of this page,
creating an insert to the A-155 GLIDE section for returning a 156-quantized,
PRE-OUT signal. You said that such an insert should be placed between Pin
8/TL064 --- and ---- Pin 4/CD4053. I asked Shawn ( US Rep ) to
cross-check your instructions with the service manual since they did not
seem to match my A-155 PCB. I think the service manual and therefore your
advice might have been "backwards".

According to Shawn, the service manual shows, as you said, Pin 8/TL064
connecting to Pin4/CD4053, and Pins 3 and 5 of CD4053 connecting to the S/H
polarity jumper. My PCB has this "switch" and jumper the other way
around....so Pin 8/TL064 connects to center pin of jumper, outer pins of
jumper still connect to Pins 3 and 5 of CD4053, and Pin 4/CD4053 connects to
a cap and Pin 12/TL064. Phew.

OK, so the mod should actually go between pin 8 of TL064 and the center pin
of S/H jumper, correct

While you have the schematics at hand........ I also asked about adding a
set of AC coupling caps and a switch for when I want to use A-155 as graphic
VCO. I've been trying to decide where to place them so that I can effect
both PRE and POST outs with one cap per CV row. I could wire things around
Pin 8/TL064 to make it work, but can I put the caps between Pin7/TL064 and
R3 so that both outputs are AC coupled

I sincerely appreciate you time and your help. Thank you.

Nicholas Keller

=============================

>From: "Dieter Doepfer" < hardware@... >
>Reply-To: Doepfer_a100@yahoogroups.com
>To: < Doepfer_a100@yahoogroups.com >
>Subject: AW: 1 A-155 mod question
>Date: Mon, 19 Sep 2005 12:53:37 +0200
>
>
>
> > -----Urspr�ngliche Nachricht-----
> > Von: Doepfer_a100@yahoogroups.com
> > [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von Nicholas Keller
> > Gesendet: Sonntag, 18. September 2005 21:00
> > An: Doepfer_a100@yahoogroups.com
> > Betreff: 1 A-155 mod question
> >
> >
> > I would like to add a send/return loop to the voltage rows of my A-155
> > so I can run the signals to A-156 Quantizer before routing them back
> > through the slew limiters inside A-155.
> >
> > Any ideas Dieter
> >
> > I know I could use the PRE-OUT as my send, so a single normalled
> > socket interrupting the signal going to the slew limiter would be all
> > I'd need to add...... but where exactly can I make this
> > interruption Shouldn't it be between the center pin of J2
> > (potentiometer board)....and where that trace branches off to C2 and
> > IC3,pin12
>
>No. That's not the right point.
>
> > That seems correct to me, but all help is appreciated.
>
>No. You have to make the insert between pin 8 of the TL084 (output OpAmp
>O3)
>and pin 4 of the electronic switch (CD4053) that is used for the S&H
>circuit. An of course an additional socket is required for the insert
>function.
>
>Best wishes
>Dieter Doepfer
>

_________________________________________________________________
FREE pop-up blocking with the new MSN Toolbar � get it now!
http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/