[sdiy] coupler module

[Fdi]

Hi,

My ideal "interface module" looks like this:

- 4 output TO "outside world" (balanced +4dB line AND unbalanced -10dB line)
Overload LED for each input to this section. May be a input level pot for
each one, otherwise set final level at last module (I preffer this)
- 2 input channels to the synth, so FROM "outside world" (also in both +4
bal and -10 unbal)
- 2 headphone jacks with vol control (L or R switch selectable for each of
the 4 outgoing channels)
- and very important: a "mute all" control, sort of a panic button. May be
relays or something more elegant that cuts the signal inmediately when you
push it, to protect your ears and your speakers. I think this is VERY
important.

I would build this for a medium size modular. But for a larger system I
preffer to have two or more of this modules each with 2 out, 2 in, 1
headphones, 1 panic.

You may even forget about the 2 inputs section, since you normally have one
or more preamps on your modular, usually associated to the envelope
follower, that can be used for anything.

A LED indicating amplitude at the end of the output sections would be useful
too (so, overload just when entering the interface and amplitude just before
leaving the interface)
The two inputs should have overload LEDs too.

No EQ at all and using best possible op-amps and components, so the transfer
to and from the outside world is as transparent as possible. I even preffer
not to have control of amplitude at this module, just good attenuators to
"pro" and "consumer" line levels.

I would keep the 2 input channels line level. If I  use a good microphone
that needs phantom power I use a little good mic pre to condition the signal
and power the mic.
--



f
*




> De: "Czech Martin" <Martin.Czech at micronas.com>
> Fecha: Tue, 26 Aug 2003 10:34:02 +0200
> Para: "Sdiy (E-mail)" <synth-diy at dropmix.xs4all.nl>
> Asunto: [sdiy] coupler module
>
> Every synth needs a coupling module to the tape machine or mixing desk.
>
> I plan to build some soon, containing:
>
> -4 balanced inputs, 2 balanced outputs (trafo or electronic)
> -2 or 4 (several) unbalanced inputs (for other synths)
> -input or output scaling circuits (the analog synth can have +-13V or
+-100mV
> as extremes), the usual levels are -10dBu = 0.245 V RMS ~ 0.35V peak
> or   6dBu = 1.55  V RMS ~ 2.2 V peak
>
> assuming that 0 dBu = 0.775V RMS and sine wave form.
> So gains of 37,    0.29,  5.9 , 0.045
> or 0.027, 3.4,   0.17, 22    (reciprocal)
> can be needed, so a range of 37 to 0.027 seems to appear.
> This is no problem since resistor networks can be changed
> if necessary. Plug in connections of resistors on the PCB
> seems to be a good idea.
>
> -A good question is if any EQ is needed. Shelving bass and treble
> and perhaps some mid bell shaped EQ.
>
> I'm not sure if this needed. It could save a mixing desk.
>
> -Another question is if any external effects send/return is needed
> -Certainly a level meter plus overload indicator with hold/reset
> is needed for the line out.
>
> If all features are build, I end up with a little mixing desk.
> That is certainly too much.
>
> So what is your practical experience?
> What is needed?
>
> Martin Czech
>
>
>
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