deniss77
Newbie level 4
The main jist of my post is this: I would like to attempt bypassing a power amp and maybe even the pre-amps in my receiver to get to the purer signals right after the DSP (digital sound processor). The central question for what follows is this: can I tap or split a signal in the circuit board and route it to an external pre-amp input without disrupting the power trace downstream and subsequently ruining the equipment completely?
I have an Onkyo DVD receiver, DR-UN7, which is part of a shelf mini-system. I like it because it can play SACD and DVD-Audio, among most other formats conceivable, and has 5.1-channel surround sound capability.
Shortcoming: there is no pre-out for the main fronts (only the speaker-level terminals)! And there are no other outs I could use to get around this problem. The amp is only 16Wpc into 8 Ohms with THD 5% at rated power. This sounds really bad on paper, though in reality, I never heard it distort. Still, I want plenty of headroom to drive my main fronts.
Current set-up: for the main fronts, I use a line-out converter to step the signal down to line-level, then I use Onkyo A-RV401 (integrated amp, 100 Wpc) to drive my main fronts (Paradigm Mini Monitors v.4). For other channels, I use Yamaha DSP-E492 (integrated amp, DSP, 60 Wpc) to drive center (Polk CS2) and rear surrounds (Infinity US-1). It's a budget set-up, which sounds good, but I like a challenge, and it's difficult not to want to make further improvements to what you have
First mod seems simple enough: I want to either bypass or incorporate a switch to bypass the built-in power amplifier in this unit and obtain pre-outs for the main fronts (so that there's no need to use a line-out converter). These will be added RCA outs - I'm not trying to replace what's already on the backplate of the receiver, just add to it. I have a service manual for this unit with detailed PDFs of well-labeled circuit diagrams. The power amp is housed on a separate PC board from the pre-amp, all of which the SM identifies.
Second mod might be tougher. Ultimately, I would like to bypass the preamp circuitry in my DVD Receiver and instead use an external pre-amp box, using the DVD Receiver only as a Disc Player, Tuner, and codac. To clarify, I want to keep the DSP circuitry but tap its output signals before they go through the built-in preamps and route them to a new set of RCA outs, to which an external pre-amp can be connected.
The schematic says (and I would be happy to post it or email it individually) that the built-in power amp is on a separate PC board. The pre-amp and the DSP share the same PC board. There is an IC chip at the heart of the pre-amp board, which I believe is designed to do the switching between different inputs (i.e., tuner, dvd) and different listening modes (i.e., 2-ch, 2.1-ch, 5.1-ch, DTS, DVD-Audio, etc). It appears that the pre-amps are situated after this chip, so it's the outputs from this chip that I want.
Has anyone done something like this, and is it possible to design a new set of RCA outs like I mentioned without ruining downstream circuitry?
I have an Onkyo DVD receiver, DR-UN7, which is part of a shelf mini-system. I like it because it can play SACD and DVD-Audio, among most other formats conceivable, and has 5.1-channel surround sound capability.
Shortcoming: there is no pre-out for the main fronts (only the speaker-level terminals)! And there are no other outs I could use to get around this problem. The amp is only 16Wpc into 8 Ohms with THD 5% at rated power. This sounds really bad on paper, though in reality, I never heard it distort. Still, I want plenty of headroom to drive my main fronts.
Current set-up: for the main fronts, I use a line-out converter to step the signal down to line-level, then I use Onkyo A-RV401 (integrated amp, 100 Wpc) to drive my main fronts (Paradigm Mini Monitors v.4). For other channels, I use Yamaha DSP-E492 (integrated amp, DSP, 60 Wpc) to drive center (Polk CS2) and rear surrounds (Infinity US-1). It's a budget set-up, which sounds good, but I like a challenge, and it's difficult not to want to make further improvements to what you have
First mod seems simple enough: I want to either bypass or incorporate a switch to bypass the built-in power amplifier in this unit and obtain pre-outs for the main fronts (so that there's no need to use a line-out converter). These will be added RCA outs - I'm not trying to replace what's already on the backplate of the receiver, just add to it. I have a service manual for this unit with detailed PDFs of well-labeled circuit diagrams. The power amp is housed on a separate PC board from the pre-amp, all of which the SM identifies.
Second mod might be tougher. Ultimately, I would like to bypass the preamp circuitry in my DVD Receiver and instead use an external pre-amp box, using the DVD Receiver only as a Disc Player, Tuner, and codac. To clarify, I want to keep the DSP circuitry but tap its output signals before they go through the built-in preamps and route them to a new set of RCA outs, to which an external pre-amp can be connected.
The schematic says (and I would be happy to post it or email it individually) that the built-in power amp is on a separate PC board. The pre-amp and the DSP share the same PC board. There is an IC chip at the heart of the pre-amp board, which I believe is designed to do the switching between different inputs (i.e., tuner, dvd) and different listening modes (i.e., 2-ch, 2.1-ch, 5.1-ch, DTS, DVD-Audio, etc). It appears that the pre-amps are situated after this chip, so it's the outputs from this chip that I want.
Has anyone done something like this, and is it possible to design a new set of RCA outs like I mentioned without ruining downstream circuitry?
