Using Pre-out / Main-in loop for Ports

  • 27 January 2024
  • 3 replies
  • 96 views
J

NAD stereos (vintage as well as new but retro NAD C 3050) among others have Pre-Out and Main-In ports to allow users to get between the pre-amp and amplification functions of a given integrated amp.  

I believe this would allow Sonos Port to stand in the middle … receiving analog signal from the integrated amplifier via pre-out port (into Sonos Port In) and separately distributing analog signal (from any other Sonos device) via output port to the Main-In on the integrated amplifier.  

I recognize that this requires the music to go through a A->D encoding and then back D->A with the attendant delays (computational and networking).  But, it should also allow any natural function of the pre-amplifier to be passed through without any fiddling of buttons to switch inputs/outputs and it should ensure than music being amplified by that integrated amplifier is time-wise synchronized with all other Sonos devices.  

Am I right ?  The diagram (box and arrow) on the following post to this community has what I’m thinking is the right way to think about this.  The pre-amp and amp just happen to be in the same component.  

 

The answer to this will drive my purchase of one of these integrated amplifiers that has the capability of jumping between Pre-out and Main-In like the NAD mentioned here.  

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3 replies

J

I found this on another ‘port’ related thread. 

<quote>

… The ideal way is to use the “tape monitor” selector that was once common. You attach the Port output to the tape/record input on the amp, and the amp sends the signal from that input to the speakers regardless of which source is selected. This is nice because when you aren’t using your Sonos speakers you can turn the tape monitor off and bypass the Port.

... The other method is to use “pre out” and “main in” connections that also used to be more common. The pre out goes to the Port input, and the Port output goes to the main in. The downside to this arrangement is that the Port will always be part of the signal path, even when you’re not using your Sonos speakers


</quote>

Any thoughts from this group on the pros/cons of the Tape-In Monitoring approach versus pre-out/main-in approach.   Control of volume, tone, loudness, etc?

Schlumpf
Userlevel 7
Badge +16

@jameicman 

I just can tell about my own experiences with the pre out version and this for me worked well. 
When I liked to use phono directly just on the amp itself, I selected „phono“ as source. 
If I liked to use Sonos streams or phono via pre out together on Sonos speakers and the amp, I set source to the input the port was connected to. 
No problems in volume or sound adjustment at all. 

Ralf
Stanley_4
Userlevel 7
Badge +22

The biggest issue I had with putting devices in the pre-out amp-in connections is that any noise from the connected devices is amplified at full volume, instead of being attenuated by the preamp’s volume control as the tape ports are.

I had a reasonably quiet device (don’t recall the ratings) but the sound difference was easily apparent when listening at anything but high volume levels.

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