Marantz av7005 vs av8801 vs Theta Casablanca

In my experience, the Theta stuff is designed to be very fast/clean.  It is conventional op amp I/V after the dac with no Class A or waveform smoothing warmth.  I suspect it is a bad match to your Emotiva amps, which are very fast/neutral.  The Theta will likely do better with a very warm or Class A based amp.

the AV8801, on the other hand, is a very warm/slow sonic signature. I suspect this is the better option in your situation, but you might feel it is too warm/slow.  You could try some silver internects and/or speaker wire if you thought it was still too warm.  

Thanks Auxinput. I was unaware of the class A output section in the Marantz, do you know if the av7005 is also class A output?

I am planning in the future to use the Emotiva amps for the low end and something tube or class A for the mid/high on the front 3.

Side question, have you ever done an A/B comparison of the Emotiva amps in class A vs A/B? I was not able to tell the difference, however we had a cold snap this weekend and my girlfriend and I were listening to the system. I switched the amps to A mode, to warm the room, she stopped dead in hear tracks and said what did you do. Apparently her hearing in much better than mine, makes me question a bi-amp setup.  

I don’t know that the Marantz has a Class A analog stage.  I do know that the AV7005 (and their other processors) will have a fully discrete analog output stage.  They also typically use a slow slew rate op amp for the DAC I/V stage.  This give the sound more warmth and a slight rolloff in high frequency response.

before you start looking at tube amps, I would upgrade the fuses in the Emotiva to Isoclean fuses.  There are two 10A small 5mm x 20mm fuses accessible from a bottom panel.  There are also two 1A small 5mm x 20mm accessable be removing the top cover.  The Isoclean will remove a lot of the harshness and help warm up the sound a bit.

the older Marantz equipment was very warm/slow.  If you feel it is too slow, you can try looking for a Marantz AV7702, which uses the newer HDAM circuits that are faster slew rate.

I have heard the Emotiva Class A mode. It is not a super warm/rich sound.  It keeps the general Emotiva fast/neutral sonic signature, but it smooths out the sound a bit, making it a tiny bit softer and laid back.  It is very subtle.  When the Emotiva Class A switch is off, the sound is somewhat bright/harsh.  The Emotiva circuit is a compromise on this, so when you have Class A switched off, there is waveform crossover distortion because the circuit is not designed strictly for Class AB.

i never recommend a bi-amp setup unless you are running an active crossover or have multiple active full range outputs (such as on the Classe CP800 preamp).  The dual output bi-amp configuration on these processors almost always degrades sound quality.  It sends full range on the normal left/right outputs.  However, it looks at the actual waveform used by this and compares it to the original by using an opamp circuit and then subtracts the “used frequencies” from the full range signal and then outputs this “converted” signal to the upper bi-amp outputs.  In my experience, it is always best not to bi-amp at all and just focus on using the best amps you can.