So, we have a client ready for an upgrade. The AVR is a good solid unit. In trying to keep the budget down I thought I can put a 4K Apple TV behind the new 4K TV, leave the old cable box in the rack and use the TV's optical output (set to the AVR's ATV input) for the ATV, when using it.
Anyone use this scenario? Was it reliable?

I don't think I have tried exactly what you are mentioning, but be aware that optical has a serious physical limit. I doubt if I would trust over 12 feet. I tried some longer ones many years ago and there was no way.

We do this exact thing all the time. Sometimes we do up and overs with 35ft+ FO's with no problem.

Well there ya go

I had a 30 and a 50 say naaahhh

I don’t know if they still make custom cables, but I have a bluerigger 45’ that works fine.

Ethereal has the MHX series of Toslink. They are in-wall rated and good to long distances. Also good prices.

I've used them out to 30'. They have even longer ones that I wouldn't hesitate to use.

Would using an RG59 or Quadshield COAX with an optical>coax adapter (behind the TV) be any better for a distance of approx 40'

We frequently end up using the RG6 Quad we always prewire to TV locations for this exact purpose. Optical->Cox converter at the TV and then at the rack end feed an AVR or distributed amp. Never seen any issues atbelow and 100+ feet.

Thanks!!!

I use that optical audio connection from the TV for seperate Roku boxes and sound bars a lot, which works good. The only hiccup could be getting the digital audio settings to match with the AV receiver during installation.

? Not sure what you're saying. This model has no optical output

We use these as it can input optic, coax or analog and outputs all 3 at the other end.

[Link: greenaudiovideo.com]

The scenario you describe may work fine, but there are a few things to keep in mind. First, make sure that both your TV and AVR support the audio formats that the Apple TV outputs via the optical port. Some TVs may not upconvert audio properly, so this is important.

Additionally, using the optical port may limit some premium audio formats, like Dolby Atmos. If you want the best audio experience, check to see if your AVR supports HDMI ARC, as this may provide better sound quality.

As for reliability, many users have reported that this setup works fine. However, you should check the audio settings on both the TV and AVR to make sure everything is working as intended. Finally, placing the Apple TV behind the TV can be difficult to access or adjust, so make sure you have easy access to the ports when needed. If you have tested or know someone who has used this setup, please share your experience for everyone to refer to!