Audio output for a non-HDMI pre-amp

I have a McIntosh MX 135 A/V pre-amp which has balanced outputs for 7.1 and has component instead of HDMI inputs.  Not wanting to upgrade to the latest McIntosh HDMI capable unit (very expensive), I was thinking of having the HDMI sources (blue ray player, cable TV, Apple TV) directly plug into the TV and using the optical audio out from the TV to supply the audio to the McIntosh which in turn would supply my 7.1 system.  

Alternatively, I noticed that the blue ray player I am interested in, the Pioneer Elite UDP-LX500 has several audio output options including 1) analog audio out via traditional RCA jacks, 2) coaxial digital audio out and 3) toslink digital audio out.  Would I get better sound, from the blue ray player, if I output the audio signal directly from the player to the McIntosh and if so, which audio out option would work best.  

The McIntosh has these specs: DTS ES & Neo:6,
Dolby Digital EX, DTS-ES, Prologic II
I had an MX135 and it was a great piece, when I upgraded I went with Anthem D2V as the MX150 was like 10-11K and I couldn’t justify it. But the Mc sounds way better. I think as mentioned if you can get your hands on an Oppo with 7.1 analog out and digital inputs would open more options. With the newer processing within the Oppo for DTS Mastersound and the Dolby counterpart you will benefit via the 5.1 input on the MX135. And with the digital in on the Oppo from the TV and other sources you have a more current decoding of the soundtracks. Look for a Blu-ray player that has 5.1 or 7.1 outputs. I think Cambridge makes one.
The last thing I would ever do is let the TV do any audio processing.  Either us the toslink/coax outputs into your mac or buy that pioneer and use 5.1 or 7.1 outputs to the mac.  Using a digital cable will cut down on the number of interconnects needed and help avoid a mess.  Everything should have digital outputs (except new Apple Play) which can all go into the Mac.  
depends on the tv, some pass 5.1 and some do not.  if it does pass the bitstream, either method is just fine.  
I may be late to the game, but I find the sound from my player to my DAC (via coaxial) surpasses the sound of the player to the HDTV (via HDMI) then to the DAC (via optical cable) by a noticeable margin. The TV seems to lower the sound quality a fair amount. I'm my 2 channel tube system, I use the player direct for better sound, and use the TV output to DAC for TV programs only.

I think you also created the same thread about your situation somewhere else here on Agon forum. Like I have explained everything to you before in another thread you created. Do not connect using optical digital out of your TV to your MX135 processor as they will degrade the sound by quite a bit. 

It's time to ditch your MX135 and get a newer HDMI equipped processor that supports lossless DTS HD Master Audio & Dolby True HD formats found on bluray discs. 

If you aren't looking for a HT preamp processor that can support 4K HDR, Dolby Atmos/DTS-X, then you will be better off looking for a used one. There are plenty of options out there that will sound better than your MX135. 

I highly recommend looking for a used Classe SSP 800 av preamp processor. This model has been discontinued 2 yrs ago. It was first introduced back in 2008 and discontinued in 2017. This unit originally did retail for $9500 when it was in production and nowaday can be had for around $3k to $3500 used due to lack of supports for 4K, Dolby Atmos, DTS-X. But the SSP 800 does support 1080p video (full HD) as well as those lossless surround sound formats such as DTS HD MA & Dolby True HD found on bluray discs. It has HDMI inputs & outputs. 

This Classe SSP 800 will sound way better than your MX135. The sound is superb and phenomenal for both movies and music if you use it as a stereo preamp for music listening assuming you have a good quality front end source components. It even sounds better than the newer McIntosh MX122 & MX150/151 av preamp processors. 
The sound was very resolved and highly refined when paired with high end power amps and speakers. 

I used to have the Classe SSP 800 in my dedicated reference high end theater room. Highly recommended if you aren't looking for a preamp processor that supports 4K, Dolby Atmos, DTS-X. Again, the SSP 800 does not support 4K video nor Dolby Atmos / DTS-X.