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Connecting external preamp to AVR

In a recent forum discussion seeking advice about a new streamer one responder observed money would be wasted if the digital signal was being fed to a home theatre receiver because “[I]ts highly inadequate preamp section will suck most of the goodness out of any good DAC.” Also “[F]eeding that nice, high-end signal into an AVR is like putting crappy tires on a Porsche — it largely defeats/undermines the purpose (and expense) [of upgrading the streamer/DAC components]”.

If the sound quality is being undermined by the preamp section of the AVR I would upgrade to a separate preamp but am unclear about the proper connections.

Currently I input the signal of a Bluesound Node 2i and Topping D90 into a Denon AVR. I use a coax cable from the Bluesound to the DAC (bypassing the internal DAC of the Bluesound) and RCA interconnects from the DAC to a selected input on the AVR.

In the chain referred to above it was stated “Since your Denon has preouts, all you’d need to do is connect the front L/R preouts from the Denon to an input of your choice (or HT Bypass if it has one) on the stereo preamp and that’s pretty much it. Choose that input on the stereo pre when you’re doing HT and another input when listening to streamer, CD player, etc. That’s really all there is to it, and the AVR will be completely out of the signal path when listening in 2-channel."

The preamp I have chosen does have a bypass so that part it clear—L & R front preouts from the AVR to the bypass RCA inputs of the preamp. But then what? The latter quote above suggests to me the DAC outputs must be connected to the preamp and not remain connected directly to the AVR. Rather than make that assumption any guidance would be appreciated.


sadbird
elliottbnewcombjr
5,565 posts
 
soix and big_greg made it very clear after I got it backwards (sorry everyone).
....................................

big_gregs diagram says a thousand words:

" Why? Because of space limitations I have a combined 2 channel / home theater system. I don't want to use the AV processor for two channel listening.

When listening to 2 channel, it looks like this: Source --> Preamp --> Amp --> Speakers.

The HTBP allows me to use the same amps and speakers for the front two channels. The volume control on the preamp is disabled and the signal from the source goes to the AV processor, which controls volume, room correction, etc.

When listening to home theater, it looks like this: Source --> AV processor --> L/R outputs --> Preamp --> Amp --> Speakers.

As the name implies, the signal bypasses the AV processor and goes to the amps/speakers with the simple push of a button, allowing you to share the amps for the front speakers between two separate systems."
.........................................

see the end, not beginning of this

https://forum.audiogon.com/discussions/avr-internal-2-channel-audio-mode-or-ht-bypass-external-equip...
ricred1
2,058 posts
 
tony1954,
"Best thing I ever did was running a HT bypass." I agree!
sadbird OP
22 posts
 
Interestingly I received a message from a well-known audio manufacturer who said "The Denon L and R pre outs are part of the preamp circuitry with the same shortcomings" indicating that the volume but not the sound would not be improved by adding a separate preamp connected to the preamps. There might be a different result if the Denon had audio in/out bypass jacks.    
ricred1
2,058 posts
 
I could be wrong, but bypass is usually a function of the 2-channel preamp. In my case I have to designate one input as the HT bypass on my 2-channel preamp.
sadbird OP
22 posts
 
I think he may have been referring to the main in/pre out connectors that some receivers used to have that typically were joined by metal jumpers. It is rare to see those anymore. And in reply to ricred, if employing the method recommended by others (particularly soix) you correctly connect the preout from the AVR to the bypass of the separate preamp and select that if home theatre is being used. The streamer/DAC is connected to any other input of the preamp and select that input when listening to 2 channel.
I referred to the manufacturers comment above only to point out that in his opinion connecting the preout of the AVR to the separate preamp will not improve the sound because the L & R preouts of the AVR apparently are part of the AVRs preamp circuitry and have the same shortcomings that and others in this forum have noted in the preamp generally.Of course this raises the question: is it really worth investing in a separate preamp if there can be no sonic improvement to 2 channel listening. This manufacturer says there can be none yet others have done it and report great results.       
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