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In the zone (hacking the Denon AVR1905 to become multi-zone)
Previously, on home improvement: I bought a Denon 1905 7.1 amplifier, to serve surround sound in the living room and stereo music to the kitchen.
To my horror, when I came home and turned it on, it didn’t have “Zone 2”.
WTF?! The product brochures I found on the internet said it has it. The product manual specified clearly how it should be operated. (well,
The remote didn’t have a “Zone 2” option on its mode selector, and the on-screen menu ended at option 24 (the manual I found on the internet says option 25 is “Power Amp Assignment” – that’s the one you use to switch between 7-channels and 5+2 channels). Argh!
The downside of buying an 8-year-old amp is, it lacks internet resources. It took an afternoon of internet searching before I found someone commenting,
“Sorry for flogging a dead horse, but doesn’t the 1905 Singapore version not have the Zone 2 capability? That’s what irritated me because I couldn’t really rely on reviews written by US reviewers. “
Which could either mean Denon models differ between territories, or that some local distributors are re-numbering the models. So I downloaded its service manual and opened it up to compare the board models, and they match: it really is a 1905. That’s frustrating, but also provides a glimmer of hope: Denon already issue 5-10 amplifier models each year, which is a lot. I bet they wouldn’t want to issue 3-4 times that number in models.
So I started reading the service manual thoroughly, and indeed, it has several (territorial) sub-models:
Of course, the CPU and main boards are similar on all sub-models. One of the differences is the analog input board (INPUT-VOL), which seems – in the E3 model – to have additional relay switching the output going towards “surround back”, and twice the volume controlling components:
So the use of the non-US sub-model of the amplifier would not allow me to control volume for Zone2, or the switching of the regular inputs (CD, DVD, AUX) to it. In my application, I want zone2 to be connected to computer audio, so I can have the surround-back bus permanently wired to the PC (by hooking the PC to the pre-amp output jacks which can also be used for input), and control the pre-amplified volume through the PC rather than through the amplifier. I just need to make the amplifier “think” that it is the US model.
As the CPU board is similar between all models, I was looking for a jumper or DIP switch that controls what sub-model it “thinks” it is. I took the amplifier apart and didn’t find such jumper, but did find a caption on the printed circuit board that specifies how the sub-model is determined:
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AREA (57P) | R216 | R218 |
---|---|---|---|
E3/BKEU | 100K | OPEN | |
E2/EK | 100K | 180K | |
GUT/G1C/G1K | 100K | 180K | |
N | 150K | 100K | |