Bi-amping question - XLR out split

It’s usually fine to just use adaptor splitters or Y splitter cables, with no degradation of note. Electrically that’s the same as preamps with dual outputs - it’s just a convenience to have the extra outlets right there.

If you find a situation where it causes problems, then that preamp was probably already marginal into a single amp. What you want to avoid is a pre with high output impedance (> 1K ohms) into amps with low input impedance (< 10K ohms, or < 20K ohms for dual amps). That’s more likely to occur when mixing tube pre with solid state amps, but in most cases even that is fine. The last few tube preamps I’ve owned have had output impedances <= 300 ohms, and will drive pretty much anything (even twice) with no problem. 

Just be aware some amps spec a much lower input impedance on their XLR inputs versus RCA, in case that becomes a factor. Though rare, you could find use cases where RCA is the better choice, based on that alone.

mulveling

...  some amps spec a much lower input impedance on their XLR inputs versus RCA, in case that becomes a factor. Though rare, you could find use cases where RCA is the better choice, based on that alone.

That’s a fair point but it’s actually the other way around - you’ll get the higher input impedance on the balanced (XLR) inputs.

That’s a fair point but it’s actually the other way around - you’ll get the higher input impedance on the balanced (XLR) inputs.

Ooof, how did I get that mixed up - thanks cleeds.

Good to know, about the XLR Y connector, at least for that i can include a bunch more preamps to look into for the upgrade.  
 

need to recheck the input impedance at the XLR inputs on my amps before buying, thanks for reminding me.

Kevin

The Rogue Audio RP-7 (and RP-9, I believe) has dual XLR outputs, and I am using the second set for my dual subwoofers with cables about 12' and 22' long.THe addition of the subs made a huge difference in my system.

That’s a fair point but it’s actually the other way around - you’ll get the higher input impedance on the balanced (XLR) inputs.

@cleeds Unless you don't. For example the input impedance, balanced or single-ended, of our class D amplifier is exactly the same. 

Some balanced inputs are low impedance (particularly in studio gear) so might be quite a lot lower input impedance than the single-ended input. 

atmasphere

For example the input impedance, balanced or single-ended, of our class D amplifier is exactly the same. 

Yes, that's not uncommon, particularly when the balanced component is AES compliant, which of course is a feature of your products that you often tout.

Some balanced inputs are low impedance (particularly in studio gear) so might be quite a lot lower input impedance than the single-ended input. 

Quite so.