I have a dac connected with single ended RCA cables to my DIY power amp. Power amp is very simple, just RCA in and speaker terminals out.
I had read some articles, especially by REL that high level inputs from speaker terminals provide better integration as there is no delay between signal sent to speakers and subwoofers, so wanted to check if someone has used it with Rythmik and comment on it.
From whatever I read till now, I think Rythmik recommends the other way, that is to connect subwoofer with pre-amp outputs. I guess I will have to split output of dac for amplifier and sub or buy a minidsp.
Rythmik subwoofers have integration as perfect as high level inputs with LFE/Line-In. below is the technical explanations to clear doubts from Rythmik.
"We don’t have speaker level inputs. We expect the customers to use RCA. There are REL recommendation that speaker level inputs is the best connection method. You can debunk those claims because of several reasons:
1) Amplifiers such as tube amp has low damping factor meaning the amplifier output is very dependent on the speaker impedance of front speakers which is not a constant. That is the reason why tube power amp normally is associated with sloppy bass. In this case use the speaker level inputs also makes our sub sound sloppy.
2) No front speakers want to be labelled as bass-shy or tell customers in straight face that the front speakers need a subwoofer. So there is a common practice to stretch the bass response that is called bump-before-rolloff. If you check the speaker measurement plots of all speakers reviewed by Stereophile, I dare to say 95% of the speakers reviewed by it has this trait. The problem with this is the bass sounds like one-note. It is very exciting only in the first few minutes of listening. The only way to get rid of that is via a crossover/bass management. That can only be done with RCA/XLR connections.
3) When one uses speaker level inputs, the subwoofer plays a very narrow range. When customers adjust the sub level up and down, it only adjust a very small frequency band, not much of an adjustment in practice. If one uses RCA inputs and some crossover or bass management, the sub level adjustment is more effective.
4) Most class-D amps have differential outputs in that black terminal is not true ground. If a customer connects that to speaker level using 2 wires connection, it is going to fry the subwoofer amps.
So in our newer models, we begin to do away with speaker level inputs"