Best way to switch between AVR and Amp?

Go with the Niles. Another option is the Niles SS-4 speaker selector. If you go that route you would run the speaker cables from both amps in and one cable out to your Kefs. Either way you choose would not degrade the sound.

Sorry Yogiboy, I can't see the Niles SS-4 (4 in - 1 out) offering any advantage over the Niles DPS-1 (2 in - 1 out) in this application to switch 2 amplifiers. Also, both of those units only accept a maximum of 14 gauge bare wire, so the OP's 12 gauge with banana plugs is an issue. There is another option from Niles, the SAS-1, which is an automatic A/B switch. This device can be triggered by audio, video, or voltage. Even though it may be obvious to let it trigger by the output of an amplifier, I would not suggest this because if you stop playing briefly, the device may time out and switch back. The best way would be to use the Arcam for default speaker input A and the Yamaha for speaker input B. Then connect "trigger out" from the Yamaha to "control in" on the SAS-1. Speakers are connected to the Arcam when the Yamaha is off, and automatically switched when the Yamaha is turned on. This should work without a problem since the Yamaha trigger is 12V at 100mA and the SAS-1 requirement is 5V-30V at 20mA. There is also another way to make it work, a little bit unusual, but will skip this unless someone wants to know.

Thanks guys.

I can run 14AWG bare wire no problem as its accessible and the runs are only 16 feet max.

I do like the idea of convenience re: the SAS-1 though.

The greatest relief is hearing that there wouldn't be sound degradation either way.

Any experience / thoughts on the OSD Audio? Put another way, is there no sound degradation with the Niles due to build quality or the fact that such switches are unlikely to add noise / signal loss etc?

Thanks again.

Have another option that I am curious about.

What if I plug in my Arcam integrated amp into the 2 pre-amp front channel RCA inputs in the back of the yamaha receiver?

I could then run everything in the audio chain as if its a different source via direct passthrough or whatever yamaha calls it.

Only question is: Am I still getting the Arcam integrated amp sound at this point or will it me degraded / modified to being more like Yamaha (which I consider a little shallow and nasally).

Thanks

What if I plug in my Arcam integrated amp into the 2 pre-amp front channel RCA inputs in the back of the yamaha receiver?

Those front channel RCA's are outputs, not inputs. The only way to connect the Arcam and Yamaha together is to let one act as a source to the other, then speakers will always be connected to the main one. For 2.0 this might be an option, however adding more speakers or a sub for A/V will greatly complicate things.

As far as the OSD, should work fine, just more connection options than actually needed. IMHO, the only difference between DPS-1, SAS-1, and OSD is the type of operation; manual, automatic, or remote control.

Hi.. i have the Douk VU3 switch.. i have my B&W 702 S3 connected to the Douk as well as both amps (Marantz SR8015 and NAD M10 V2- for music). I have all other speaker connections with the Marantz… it is as simple as switching between the Marantz and NAD whether i want to listen to music (NAD) or home theater. It is simple and works well. The key is to keep the av out of the music stream. I have a 7.1.4 for home theater and a 2 channel driven by the NAD for music…