Any comments on DAC directly to Power amp with no

Good points George! I can't see the Opamp solution being ideal for sound quality. A genuine differential balanced circuit would seem a better choice if someone is seeking true balance components. Still not a sure guarantee it will necessarily sound better than a well implemented single end circuit.
Charles,

The Nuprime Dac-10 might be nice. I say this because I'm using the phenomenal IDA-16 integrated and LOVE it, not because of the new review out in Absolute Sound that my buddy told me about. I haven't read it as I've stopped getting the audio rags years ago. They're all rubbish.

I'll be trying a fixed attenuator so I'll find out.

All: I want to thank everyone above for your comments and suggestions. They were helpful and appreciated.

Philip from On Higher Note (Luxman Distributor) said "To truly separate the preamp stage from the L-590ax, you need to run an RCA cable into MAIN IN and then hit the SEPARATE switch. If you run balanced cables, you will also be using the preamp stage of the L-590ax”.

He had no comments if the 590ax is, or is not, a fully balanced amplifier. If we have to use the RCA main in jacks on the 590ax, it seems we are not taking advantage of the two balanced units (DAC and amp). I was told that, if RCA plugs separate the pre-amp section from the power amp, my Luxman 590ax is really not "fully balanced". I do not know or understand. The 590ax sounds great so maybe it probably is not important. Any comments on this?

My loaner Bricasti M1 DAC with volume control is due next week. My plan is:

1) Plug the Bricasti M1 DAC using balanced XLR cables into the balanced inputs on the 590ax. This means the 590ax is operating an integrated amplifier including its pre-amplifier. The Bricasti M1 will only operate as a DAC.

2) Plug the Bricasti M1 DAC using RCA cables into the RCA main in jacks on the 590ax and press the separate button on the front panel. I will turn the input selector to another setting but I do not know what setting yet (any suggestions?). This might not be important since the separate switch is on. The volume control will be done using the Bricasti M1 DAC and not the volume control on the 590ax.

The above cable wiring and operation will enable me to easily switch between integrated amplifier operation and the Bricasti M1 DAC used as a pre-amplifier (and its volume control).

It is going to be an interesting experiment. I received many different opinions for running the DAC directly vs. through the preamp section of the Luxman. Obviously, it is a very gray area and I need to try it both ways in my system. Thanks again.

"I've seen it all too many times. A typical example of this is my cd player which has both single ended and balanced outputs, the extra opamp they used for the balanced had gain compared to the single ended output, which bypasses the balanced opamp, therefore one less opamp in the signal path from the single ended output."

So, basically what you're saying, is that a manufacturer may raise the gain on a single ended components xlr outputs to make it appear balanced if someone were to look at the spec sheet? I never even considered something like that. My ex-girlfriend from Russia wasn't even that unethical.