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HT Proc/Preamp to Analog Preamp w/o passthru?

I have a surround sound processor/preamp I use for MCH that has balanced outputs to my amps. One amp is used to drive the centers and the surrounds. The other amp is for my main front R/L. The amps are of same family and sonically match allowing a good blend.

I have an analog preamp with balanced outputs that I use for 2CH which has balanced outputs to my main front R/L amp.

Problem: I want to use the same amp for my front speakers for both the surround processor and the analog amp. One obvious way is to simply swap the balanced connections at the amp when I want to switch between 2CH and MCH. Purity yes, but not exactly convenient.

Another option is to run the analog 2CH preamp into the surround sound processor and use the analog bypass but that kinda defeats the purpose of having a pure 2CH path.

The analog preamp has 2 sets of balanced inputs but it does NOT have a home theater passthru mode where the input is fixed. I am thinking use one set of balanced inputs for the 2CH path and the other for the MCH path but again, no passthru mode. Is it possible to run the balanced outputs from the surround processor into one set of the analog preamp's balanced inputs and then simply make sure the volume control on the analog preamp is always set at the same volume? If so, what volume? Would this present any kind of grounding loops or impedance matching problems? It would seem the only drawback would be making sure the analog preamp is set at the same volume level.

Ideas of a more convenient solution? I could sell the analog preamp and purchase one with passthru. :-)

Any help/advice would be much appreciated. You can tell from the post that I'm not the most knowledgeable audio chap but I do enjoy it and learning from these forums.

Thanks!
rdg238
bdgregory
1,712 posts
 
Is it possible to run the balanced outputs from the surround processor into one set of the analog preamp's balanced inputs and then simply make sure the volume control on the analog preamp is always set at the same volume?
Yes. what volume you choose depends on your situation. I would suggest something easy to remember - such as 12:00 if you have a rotary dial. You want to also be careful that you don't pick a volume level such that if you inadvertently switch to another input it risks blowing your windows out (or worse your speakers). Finally you need it at a level within the parameters of your HT setup adjustments.

I frankly think this is the most convenient solution short of a built in HT passthru. It worked great for me.
rdg238 OP
2 posts
 
Yes, that might be the best solution so far without spending additional money.

Another alternative is to stop using balanced output connections on the back of the surround processor and switch to single ended straight into the amp for the front mains. It has switches for balanced/single ended. Still a bit inconvenient though as each time you must get behind the amp and flip the switches. It also removes the ability to use balanced out of the surround processor.

Dreaming a bit here, but is there such a thing as a non-intrusive (sonically speaking) balanced switch box that does not introduce noise and has great separation between the inputs?

I can envision this alternatives but don't have enough understanding or experience to judge them appropriately. If anyone can look at these different alternatives and suggest which ones to throw out and why, I would greatly appreciate it!

The surround processor is a Bryston SP2, perhaps I just sell the analog preamp (Bryston BP26) and use the SP2 analog mode for 2CH. One of the downfalls with this option is the SP2 does not have balanced inputs so my DAC would have to connect single ended.

Sigh
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