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Balance Audo Circuit

A

Astro

I need help with a circuit design.

I am using RS232 4-wire audio output and need to bridge into another
piece of equipment.

I would like to used and build an audio bridge with matching impedance
between the input of the bridge in the output of the bridge to other
equipment.

The output of the balance circuit would also be 4-wire audio. I need a
circuit that will match impedance of 600 ohms both both input & the
out put.

I have had trouble finding what size resistors to used in the bridge
to match the impedance.

Thanks,

Astro
 
E

Eeyore

Astro said:
The output of the balance circuit would also be 4-wire audio.

What exactly do you mean by 4 wire audio ?

I need a circuit that will match impedance of 600 ohms both both input & the
out put.

Telecoms ? 600 ohms is no longer used for audio outside of that specific area.

Graham
 
A

Astro

What exactly do you mean by 4 wire audio ?


Telecoms ? 600 ohms is no longer used for audio outside of that specific area.

Graham

RS232 will be used for the line which of course os 600 ohm. This is
not being used with telco equipment but with LMR (Land Mobile Radio)
equipment.
 
D

Don Bowey

RS232 will be used for the line which of course os 600 ohm. This is
not being used with telco equipment but with LMR (Land Mobile Radio)
equipment.


RS232 is not an audio spec; it's for digital signals.

Are you trying to build a "phone patch."


Don
 
T

Tam/WB2TT

Astro said:
RS232 will be used for the line which of course os 600 ohm. This is
not being used with telco equipment but with LMR (Land Mobile Radio)
equipment.
So you want to use existing RS232 wires for audio? The short answer is
forget the whole thing. RS232 wires may be 600 Ohms. They may also be
anything else, including 50 and 900. To put audio on unshielded wires, you
want twisted pairs, but RS232 may or may not be. Your wires are probably
less than 50 feet long, and don't require matching if you drive them from a
low impedance source. You don't match speaker wires. If you insist on doing
it, one way is to use transformers, and pick the 8 or 16 Ohm tap.

Tam
 
R

Robert Baer

Astro said:
I need help with a circuit design.

I am using RS232 4-wire audio output and need to bridge into another
piece of equipment.

I would like to used and build an audio bridge with matching impedance
between the input of the bridge in the output of the bridge to other
equipment.

The output of the balance circuit would also be 4-wire audio. I need a
circuit that will match impedance of 600 ohms both both input & the
out put.

I have had trouble finding what size resistors to used in the bridge
to match the impedance.

Thanks,

Astro
RS-232 is a bi-directional *data* communication specification and is
not related to audio.
So your info is incorrect and incomplete, making for no answer.
 
R

Robert Baer

Eeyore said:
Astro wrote:




What exactly do you mean by 4 wire audio ?





Telecoms ? 600 ohms is no longer used for audio outside of that specific area.

Graham
I have seen 500 ohms as a reference in studio work...
 
R

Robert Baer

Eeyore said:
Astro wrote:




Is it ? That's news to me ! I think you'll find it's not actually.

RS232 is a digital serial data protocol.
http://en.wikipedia.org/wiki/Rs232

It seems to me you're confusing hardware with communications standards.

Graham
I think that the full RS-232 spec covers both hardware and protocol.
 
E

Eeyore

Robert said:
I think that the full RS-232 spec covers both hardware and protocol.

It standardises the connector(s), their pin connections and voltage levels AIUI but
is widely ignored anyway in recent kit.

Graham
 
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