[alex]

hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.
Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.
I will do this by grounding xlr pin 3, as usual.
Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

thanks
alex

[PStamler]

On Dec 8, 9:11*am, alex wrote:
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.
Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.
I will do this by grounding xlr pin 3, as usual.
Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

If the balanced source is electronically balanced rather than
transformer-balanced, unbalancing it by grounding Pin 3 is actually a
bad idea. Just use pin 2 as the hot connection, pin 1 as the ground,
and connect a 10k resistor from Pin 3 to ground. Then use the pad.

Peace,
Paul

[Scott Dorsey]

alex wrote:
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.
Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.
I will do this by grounding xlr pin 3, as usual.
Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

If you make a balanced pad inside an XLR barrel connector, you can use it
later in the future when you need a balanced pad. But on the other hand,
barrel connectors are expensive.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[geoff]

Scott Dorsey wrote:
alex wrote:
hi all, i'm about to build another resistive PAD in order to reduce
the power amp feed.
Since the source is "balanced" and the amp is not, i need to
"unbalance" the signal somewhere.
I will do this by grounding xlr pin 3, as usual.
Here the question. Is better to build a "balanced" (U type) PAD and
then unbalance the signal or is better to unbalance first and then
use an L type PAD?

If you make a balanced pad inside an XLR barrel connector, you can
use it later in the future when you need a balanced pad. But on the
other hand, barrel connectors are expensive.
--scott

Depends what you mean by expensive. Neutrik ones are, but generic's aren't,
and their 'quailty' is not dire.

geoff

[Arny Krueger[_4_]]

"alex" wrote in message
. ..
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.

Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.

This is usually effectively done by simply using the positive output of the
balanced output pair.

I will do this by grounding xlr pin 3, as usual.

That hasn't been the usual way, since output transformers stopped being
common. 99% of all modern equipment uses transformerless outputs.

Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

Just hook an L pad from the positive output to ground, and leave the
negative output flapping in the air.

[alex]

Il 08/12/2011 21.58, Arny Krueger ha scritto:
wrote in message
. ..
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.

Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.

This is usually effectively done by simply using the positive output of the
balanced output pair.

I will do this by grounding xlr pin 3, as usual.

That hasn't been the usual way, since output transformers stopped being
common. 99% of all modern equipment uses transformerless outputs.

Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

Just hook an L pad from the positive output to ground, and leave the
negative output flapping in the air.


pin 3 (or "ring", in this case) is grounded because the socket is a TRS
and is connected via a TS jack-RCA adaptor. I noticed no difference, but
i know that the "negative" signal half is "shortened" and this may be
not very good for the equipement health.
I will solder a better cable with an L PAD inside the TRS connector,
leaving the (-) floating in the air!

Thankyou all for the answers.

alex

[Arny Krueger[_4_]]

"alex" wrote in message
. ..
Il 08/12/2011 21.58, Arny Krueger ha scritto:
wrote in message
. ..
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.

Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.

This is usually effectively done by simply using the positive output of
the
balanced output pair.

I will do this by grounding xlr pin 3, as usual.

That hasn't been the usual way, since output transformers stopped being
common. 99% of all modern equipment uses transformerless outputs.

Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

Just hook an L pad from the positive output to ground, and leave the
negative output flapping in the air.

pin 3 (or "ring", in this case) is grounded because the socket is a TRS
and is connected via a TS jack-RCA adaptor. I noticed no difference, but i
know that the "negative" signal half is "shortened" and this may be not
very good for the equipement health.
I will solder a better cable with an L PAD inside the TRS connector,
leaving the (-) floating in the air!

On balance, the op amps that drive the outputs of most modern gear tolerate
short circuits well, and there is usually a building-out resistor that takes
the edge off of the short.

Any piece of gear that can't handle a short circuited output is bound to be
a warranty claim hog, and no legitimate manufacturer wants that!

[alex]

Il 09/12/2011 17.25, Arny Krueger ha scritto:
wrote in message
. ..
Il 08/12/2011 21.58, Arny Krueger ha scritto:
wrote in message
. ..
hi all, i'm about to build another resistive PAD in order to reduce the
power amp feed.

Since the source is "balanced" and the amp is not, i need to "unbalance"
the signal somewhere.

This is usually effectively done by simply using the positive output of
the
balanced output pair.

I will do this by grounding xlr pin 3, as usual.

That hasn't been the usual way, since output transformers stopped being
common. 99% of all modern equipment uses transformerless outputs.

Here the question. Is better to build a "balanced" (U type) PAD and then
unbalance the signal or is better to unbalance first and then use an L
type PAD?

Just hook an L pad from the positive output to ground, and leave the
negative output flapping in the air.

pin 3 (or "ring", in this case) is grounded because the socket is a TRS
and is connected via a TS jack-RCA adaptor. I noticed no difference, but i
know that the "negative" signal half is "shortened" and this may be not
very good for the equipement health.
I will solder a better cable with an L PAD inside the TRS connector,
leaving the (-) floating in the air!

On balance, the op amps that drive the outputs of most modern gear tolerate
short circuits well, and there is usually a building-out resistor that takes
the edge off of the short.

Any piece of gear that can't handle a short circuited output is bound to be
a warranty claim hog, and no legitimate manufacturer wants that!


yes, the equipement manual claim to "accept unbalanced connection". On
TSR sockets this mean that people are allowed to insert tip-sleeve
jacks, which will shorten the negative half.
by the way i will leave the contact open...

alex