For what purpose do you need a tuner? 

Let’s be sure that we are using the proper definitions: A “Tuner” is a single function (radio broadcasts) device that can be connected to a SONOS unit that offers an analog “Line-In”. A “Receiver” (such as the RX-A780) is a multi-function device.that includes the radio function.

We can help, but we need to know which sources you want to connect to and listen through the RX-A780 and how you want to use the system. Which SONOS units do you currently own? Will you want to be able to simultaneously play the same source on SONOS units and the RX-A780?

I have several JBL Pro Audio speakers that require a hard wire and power to drive them as well as a high-end belt drive RCA plug turntable (circa 1965) since I still have very substantial record collection and watch the occasional DVD.  I currently do not own any SONOS equipment, this is why I am asking. I want to know and make sure the systems are compatible before I purchase anything or even if I need a tuner/amp. The information on SONOS seems to be obscure and those who I have spoken with seem to be reluctant in giving a straight and direct answer.  

I meant a tuner/amplifier. I was under the impression that you needed a some type of processor (tuner/amp) for audio signal to go from cable to TV to speakers as well as from audio service to speakers. Please correct me if I am wrong, I have not purchased anything new in 15+ years so I am out of sync with current methods and systems, even though I live in SONOS HQ town.

Ok, let’s break this down, and hopefully provide some additional information. 
 

A Sonos Amp has the ability to power a pair of speakers. No need to go outside for an external amplifier, at least from that point.

However, a Sonos Amp has essentially only two inputs. One is Digital, in the form of an HDMI-ARC input, designed to take input from a TV set, and the other a standard analog input, in the form of RCA jacks. So you could easily attach a phono to pre-amp, and then send that signal to the analog input, and play your records. You could then take an HDMI-ARC signal from your TV, and send that to the Amp, and the Sonos would create a 3.0 signal from the TV, assuming a Dolby Digital signal.

This is where it gets a little convoluted. When using the Sonos Amp to drive a pair of your own speakers, the 3.0 signal is from the pair of speakers, and there is no true center speaker. The center channel is considered a “phantom” speaker, and created by combining the output of the left and right speakers.

You can then add another Sonos Amp, if you choose, to drive your own speakers as surround speakers, or add a pair of Sonos speakers. This would give you a 5.0 system, with that center channel still being “phantom”. Then adding a Sonos SUB would make it a 5.1 system.

Alternately, you could go with any Tuner/amp you desire, and add a Sonos Port to it, normally used with a tape input/output to get the sound to and from the Sonos ecosystem. Your challenge here is the 75ms delay on anything coming from the tuner to the Sonos. So if you’re playing a record through the tuner, and sending the signal to both the tuner’s speakers and any grouped Sonos speakers, there will be a delay. If you’re streaming music from Sonos to the tuner, then both the tuner’s speakers and any Sonos speakers will be in sync. The downside is that in this setup, Sonos is only in stereo, and doesn’t support home theater. 

That is a lot of data to absorb. And maybe not as clear as you may like. Feel free to ask for further clarification. 
 

wileecoyote,

Are you interested in surround sound with your TV? How old is your TV? Does your TV incorporate HDMI inputs?

I have a related question - I am thinking about replacing my power amp with Amp from Sonos. The power amp is currently fed by a conventional preamp/tuner which in turn receives inputs from a turntable, CD player, etc. It in turn feeds the power amp which powers two sets of room speakers. Does anyone know if Amp can be used to replace the existing power amp, and if it will accept the preamp/tuner as a “line in” input and also allow me to power and manage the speakers via Sonos and play other Sonos based audio sources? Thanks.