Help setting up HT and Integrated Amp and Sub

I was in a similar situation as you - wanting to incorporate a subwoofer into a setup that has an AVR for movies (and the LFE output to the sub), but also ’better’ audio for 2-channel listening with an integrated amp.

It is too bad you couldn’t get the MF A3.5 int amp to work for you, because that amp has an HT Direct feature that would have allowed you to do exactly what you want w/o resorting to switches and such.

I couldn’t tell from the Exposure specifications whether it has an HT Direct (aka Bypass) feature or not.

If it doesn’t, then I think you have to use a manual RCA switch device in front of your sub with the outputs from the AVR and Int Amp.

I assume you plan on connecting your AVR L&R front preouts to one of the RCA inputs on the int amp to drive your front speakers?

If you could figure out the hum issue with the A3.5, that would be, imho, the cleanest solution.

I also have an Oppo player: hdmi connected to my AVR, and L&R analog outputs connected to my Musical Fidelity A5 int amp for CD inputs.

HDMI w/ AVR selected for movies: the A5 amps my front speakers and the sub is controlled from the AVR.  For music, AVR is off, Oppo drives the A5 CD input, A5 preouts drive the sub for clean rocking music goodness.

If you'd like to see diagrams I've done up that show the connections in my system, I can post links here.

It all works slick and clean, no cable swapping, no switch boxes, no hum.

It could be your previous attempt to hook both the AVR and Int amp to the sub failed (eg the hum) might be because the Exposure doesn't have a true HT Bypass.  Meaning its HT input is really a unity gain connection that still passes thru the preamp which would result in the pre-outs being active at the same time as your AVR subwoofer connection.

So the switch approach is probably your best bet.

I have a MF A5 int amp with an HT Direct connection which when selected completely bypasses the preamp section of the A5 so that it only functions as a power amp.  Therefore no signal is outputted from the preout L/R connections.

This allows me to hook up my sub to both the AVR subwoofer output and the L/R preouts from the Int Amp.  No hum, no switches - works perfectly.

If I'm listening to music, source devices are connected directly the A5 and the AVR is off.  The sub gets full range from the A5 preouts and I use the sub xover, phase, and volume.

If I'm watching movies thru the AVR, I select the HT Direct input on the A5, the preamp gets bypasses, no signal from the A5 preouts, and the sub gets the LFE signal from the AVR and its bass management settings.

Here is my overall system connection diagram

http://erikt.cts.com/Pictures/hometheater/HT-Bypass-Diagram-1.jpg

And for HT/movies/multichannel sources

http://erikt.cts.com/Pictures/hometheater/HT-Bypass-Diagram-HTmode.jpg

And for 2-channel sources

http://erikt.cts.com/Pictures/hometheater/HT-Bypass-Diagram-2chnlmode.jpg

Hope that helps and good luck with your own setup.

I’d also verify that the Exposure Int Amp has ’true’ HT Direct when you have your AVR front preouts connected to one of the inputs.

With the sub connected to the preouts of the Exposure, you should not hear any signal at all if the Exposure ’bypasses’ its internal preamp section.

If you do hear something from the sub, then the Exposure has a unity gain design and the AVR L/R preout signals are still going thru the Exposure preamp section (and hence the Exposure preouts to the sub).

This may explain the hum with your "Y" connection from both the AVR and the Exposure to the sub.