Wurlitzer
Active member
Joined: 11/12/02
Posts: 3341
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Unbalanced-Balanced query
#103940 - 20/03/05 12:32 AM
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I have an unbalanced source on 2 mono 1/4" jacks. I want to plug this into a desk, which
offers a choice of unbalanced phono inputs, or balanced jack inputs. Should I:
a) plug the unbalanced jacks into the balanced jack inputs, or:
b) plug the
unbalanced jacks into jack-phono adaptors, and plug these into the unbalanced phono
inputs?
I suppose what I mean is, is there a disadvantage to plugging an
unbalanced signal into a balanced input, as opposed to keeping the entire signal chain
unbalanced?
Thanks.
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Anonymous
Unregistered
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Re: Unbalanced-Balanced query
[Re: Wurlitzer]
#103950 - 20/03/05 01:16 AM
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Probably "b", but see below.
Quote:
is there a disadvantage to plugging an unbalanced signal into a
balanced input, as opposed to keeping the entire signal chain unbalanced?
It depends upon the operating levels of the
different outputs/inputs. Some semi pro gear has unbalanced i/o running at high level
rather than the ordinary domestic level. In this case, making up an adapter cable
(unbalanced jack to balanced jack) is the better way to go. Otherwise, run unbalanced via
unbalanced jack to phono cables.
As long as you don't need to run long cables,
going unbalanced will be fine.
(If the source is at domestic level, you could
still make some cables to run the unbalanced outputs into the balanced inputs but you'd
need to find some extra gain (e.g. an Audio + Design
"Audiomate" or similar) to drive the balanced inputs to optimum level.)
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Wurlitzer
Active member
Joined: 11/12/02
Posts: 3341
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Re: Unbalanced-Balanced query
[Re: ]
#103999 - 20/03/05 10:34 AM
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Thanks. "Domestic level" is -10db, "high level" (or "pro level") is +4db, correct?
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Anonymous
Unregistered
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Re: Unbalanced-Balanced query
[Re: Wurlitzer]
#104064 - 20/03/05 01:51 PM
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Sorry, yes -10dBV and +4dBu.
Generally, domestic hi-fi and other home AV
products will be at the lower level, semi-pro mixers/soudcards/tape machines/etc. often
run unbalanced at +4dBu (more common on jack sockets than RCAs/phonos.
It
should say on the equipment, or in it's manual, at which level it works.
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18348
Loc: Worcestershire
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Re: Unbalanced-Balanced query
[Re: Wurlitzer]
#104342 - 21/03/05 10:29 AM
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There is one other thing to beware off. You don't say what your mixer is, but some offer
true 'phono' inputs -- meaning inputs intended for the output of a pickup cartridge on a
turntable. These will be on phono (RCA) sockets, hence the potential confusion.
This type of true phono input (as opposed to a simple domestic level unbalanced line
input for a CD player etc) will have a very high sensitivity compared to a standard
domestic line input, and have a built-in fixed RIAA equalisation circuit to correct the
emphasis used on vinyl records.
Clearly, this kind of input can not be used
with conventional unbalanced line level sources. Use the jack sockets instead.
Plugging an unbalanced input jack into a balanced input will work fine (albeit with the
possibility of introducing a ground loops).
Hugh
--------------------
Technical Editor, Sound On Sound
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