Originally Posted by GGA
I think Dan is referring to the 6dB you can lose if you disconnect pin 3, i.e., half the signal.
I was speaking about common or typical XLR outputs on consumer AV processors. Case in point, Theta, Classe, and now the Marantz AV7702. As I mentioned, not only are the voltages on (each of) the XLR pins typically the same as the phono output, but it's often the very same signal on pin 2 from the same preamp stage that drives the phono jack. So there will be no loss to be concerned about. But let's say there is a preamp with lower output gain, and running single ended is weaker. Would not the gain trims have enough range to cover it?
it depends on the type of balanced output. Transformer bal output vs. active balanced (designed to act like a transformer) output vs. active balanced output. They all react differently to unbalancing. Just unbalancing does not guarantee that you will have a drop in level. Don't know what Datasat uses.
Yes, they do react differently. But realize we are talking mostly about pro gear using real transformers or active ones.
The Datasat AP-20 design used the That Corp 1606 balanced line drivers. In that case, one can and should ground pin 3 when a single-ended output is desired, as it emulates a transformer electronically. Maybe someone can confirm the RS-20i output stage configuration. For some reason I am under the impression that the output stages are similar to the other pre-pros I mentioned.
Originally Posted by DanFrancis
My thought process is this: if you use the Jensen, you're pretty much guaranteed to not have issues going from balance to unbalanced no matter what equipment you're using. For me, personally, if it's one of my clients- it's a transformer to be sure the input stages are protected.
There's no question the transformers work. But what is it being protected from? Aside from the connector or the adapter, the electrical signals are identical when driving a single-ended amplifier from Pin 2 of the XLR.
Here's the ultimate point: do you really want to risk a 20,000 processor's output stage (RS20i) or even 10000 processor (LS10) or the input stage of an amplifier that cost (?) based on the "lift pin 3" theory of XLR connectors?
I do not see any risk as long as the correct adapter is used. These input/output stages are not going to break, even if mildly abused.
Some manufacturers actually handle the 3 pins properly, others are using XLR but actually handle it in an unbalanced manner.
That will work equally well without a transformer.