hello dieter,
ok, poll coming very soon!
but, how will this passive mixer be connected to the
a138a/b will it need soldering to the a138a/b's pcb
or, externaly with a patchcable to one of the a138a/b
inputs
best regards,
Bakis.



--- hardware@... wrote:

> > Dieter,
> >
> > that would be interesting as it would save me
> daisy chaining mixers and
> > loosing an i/p
> >
> > david
> >
> > David Salter
> > Senior Consultant
> > PSG
>
> David,
>
> the mod is simple:
>
> For the old version of A-138a/b remove the dual
> opamp IC1 (TL062) of one of
> the two modules and connect pin #2 of IC1 (i.e. the
> inverting input pin of
> the first opamp) of both modules. The module with
> the missing IC1 has no
> longer a output signal available. If you want to
> have a output of this
> module connect pin #7 of IC1 (i.e. output of the
> second opamp) of both
> modules. Now you have two outputs with adjustable
> levels available.
>
> For the new version of A-138a/b its similar but here
> a quad opamp (TL064) is
> used. Remove the quad opamp IC1 (TL064) of one of
> the two modules and
> connect pin #9 of IC1 (i.e. the inverting input pin
> of the first opamp) of
> both modules. The module with the missing IC1 has no
> longer a output signal
> available. If you want to have a output connect the
> output sockets of both
> modules. In this case the output of the second
> module cannot be adjusted
> (different circuit compared to the old version). But
> you may connect the pin
> header JP2 of the first module to the output of the
> second module. Then you
> have the inverted output available.
>
> For the polarizing mixer A-138c remove IC3 (TL062)
> of one of the two modules
> and connect pin #6 of IC3 (i.e. the inverting input
> pin of the mixing opamp)
> of both modules. The module with the missing IC3 has
> no longer a output
> signal available. If you want to have a output of
> this module connect pin #1
> of IC3 (i.e. output of the final opamp) of both
> modules. In this case the
> level is the same for both outputs. The master
> control of the second module
> has no function.
>
> We already discussed a simple "mixing expander"
> module that could be used to
> add 5 more inputs to A-138a/b. It will be about
> 20-30% cheaper than an
> A-138a/b as no integrated circuits and no power
> supply are necessary for
> such a simple module (only a front panel with five
> sockets, five
> potentiometers+knobs and five resistors). How about
> a poll
>
> Good luck,
> Dieter Doepfer
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>

Bakis Sirros - Parallel Worlds
1 group owner
http://www.parallel-worlds-music.com
http://www.myspace.com/parallelworldsmusic
http://www.shimarecords.co.uk
http://www.rubber.gr
Athens-Greece



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