After market Amp
 

Am going to put new front speakers and sub in new B7 S4. Was wondering where is the best place to get signal? At the head unit or at the bose amp. Thanks

after bose amp

Ahem
 

Since the B7 doesn't use any fiber optic signal to the amp from the deck, but sends an analog single-ended common-grounded preamp signal, I would totally get the signal in between the HU and the Bose amp, NOT after the Bose amp.

You can probably use the signal just fine at the Bose amp - no need to go to the HU.

If you were just running a sub, I would go after the amp. With a front/sub system, I would totally go before the amp.

Re: Ahem
 

The car came with sym II head unit but I have ordered a rns-e to put in it. Don't Know if that makes a differents or not. Have been told to vag the Nav as non bose to get better signal.

RNS-E, SYm, Concert, all have same OP types

You'll get really annoying pops if you pick it up straight off the HU or before the amp.

We do it ALL the time at my shop
 

no clicks, no pops.

Yeah right!

Seriously... 2 A3s in the last month, and an S4 a couple months ago
 

No pops at all.

I'm actually confused as to why you think there should be pops or other noise... it's a single-ended preamp output. You could get alternator whine fairly easily if you weren't careful or used the wrong gear... but pops?

We do 80% of our systems using the OEM radio. We haven't had any issues with Audi head units relative to the general public. Lots better radio than Infiniti or the new X3 Bimmer. We've done Acuras, Mazdas, BMWs, Audis, Infinitis, all without any CleanSweep or 360.

I did it with no pops or clicks right at the head unit too.
 

You never want to pick up the signal after the amp if you're going to amplify it again. You would overdrive the low level input of your aftermarket amp which would then cause clicks, pops, and distortion.