Originally Posted by Wafflebird
OK, I have a question. I have the SR7012 in my living room and am planning on retiring it to the bedroom to replace an underwhelming Denon AVR-X3200. Not that it sounds bad but it replaced a Yamaha RX-V2500 (currently serving as my office system receiver, this thing has power) and it has just been kinda MEH....... The 7012 move will make room for an SR8012 if I decide to go that route. My question is that a quick review of the specifications and information on the SR7012 and SR8012 show basically the same thing as far as internals regarding processing and more importantly the DAC's. They are the same yet I see a lot of people who discuss a "Huge Improvement" in the sound quality when going from the 7012 to the 8012. I am wondering if this is either placebo effect or possibly a bit of purchase justification?
I have recently been lucky enough to have received an Oppo UDP-205 (Joined the mailing list the day the offer came out) and am looking forward to getting it installed along with the 8012 but I question what real discernible difference I may be able to actually expect. Now I know the Oppo will be awesome but I do not presently have it hooked up to the SR7012 yet.
So any of you that have swapped out the SR7012 to the SR8012 what has your experience been? I know the SR8012 is better built with the copper chassis and the toroidal power supply. I know it has a bit more power but with the same DAC's how can it sound any different in the same room with the same equipment?
My system is a pair of Definitive Technologies ST-L's an CS-8080 HD Center a Supercube Reference and 4 in ceiling surrounds, along with the Oppo (To be installed) and a Roku, Dish Hopper and a 65" Panasonic Plasma and a Qnap server with about 9,000 songs mostly lossless. All componentry is hardwired to Ethernet.
- Omitted -
Originally Posted by Selden Ball
As you say, the noise and distortion specs listed in their manuals are identical. Pictures of their insides show that while the AV8012 and AV7012 seem to have identical digital electronics, they have quite different amp designs. Those design differences might result in somewhat better signal to noise and distortion levels in the SR8012 than are listed in its manual. Pictures of the SR8012's insides are shown at https://www.avsforum.com/marantz-deb...at-cedia-2017/
and pictures of the SR7012's insides can be seen at https://www.homecinemamagazine.nl/20...2-av-receiver/
However, don't forget than many people experience an unrecognized "expectation bias" when they listen to a device that they know is "better". I dunno to what extent that might apply to reviews you've read.
The DAC dhip itself is only part of the conversion from digital to analog. Differences in the accompanying analog circuitry can have a significant impact on the quality of the resulting audio. I dunno how much, if any, differences there are in those parts of the SR7012 and SR8012 designs, though.
- Omitted -
Subjective reviews, many of them by owners, are mainly what's available on these two units. The following provides selected information on the design of the two units. How and if the differences in the designs would translate into audible differences in an owner's system, or in comparing the units in a store or other location, is an open question.
It appears there are no identical circuit boards between the two units. Just for information, the AV8012 does share several circuit boards with the Denon X8500H AVR.
The digital circuits, audio and video, appear to be very similar between the units. On the digital audio side, the units share the same DAC; the 8-channel AKM AK4458.
The units have similar switched-mode power supplies.
The linear power supplies are different. The SR8012 has a toroidal transformer and 44,000 uF of capacitance. The SR7012 has an EI frame transformer and 30,000 uF. The toroidal transformer likely has more capacity (VA rating) although this is a guess, along with a less intense external magnetic field, which should help reduce noise. The EI transformer will pass less noise to its load, than the toroidal unit since its windings are further apart. The greater capacitance in the SR8012 will help maintain output during transients and will reduce power supply ripple. The level of ripple is inversely proportional to capacitance. Overall the SR8012 appears to have a much more robust power supply.
The units have the same volume control. All of the analog signals for the main zone pass through this volume control. Both units have HDAM output buffers. The SR8012 HDAM's get power from a transistor regulated power supply, similar to the one used in the AV8805, but using a lower voltage. The SR7012 HDAM's receive power from an IC voltage regulator that is shared with all of the opamps in the unit. The quality of the power supply is important to the performance, noise and distortion, of the HDAM's. The SR8012 has a higher quality power supply for its HDAM's.
The HDAM circuitry itself is essentially the same between the two units although the circuit boards are different.
The preamp outputs (muting) in the SR8012 are all controlled by relays. This is the same as in the AV8805 and AV7704 and is the preferred method. The SR7012 has relays for the L and R outputs, but uses bi-polar transistor circuits for the remainder of the muting circuits. These bi-polar circuits work well and are more common than relays, but aren't the preferred method.
As noted above the linear power supply for the amplifiers in the SR8012 is more robust than the power supply for the SR7012. The power amplifier circuits, and individual circuit boards for each channel of the SR8012, are shared with the Denon X6400H and X8500H, and are the best that Denon/Marantz offers. For some details; the differential amplifier input circuits in the SR8012 have a current mirror vs. resistors in the SR7012. This should significantly reduce distortion, especially as the load increases. The voltage gain stage in the SR8012 also more robust which should reduce distortion caused by loading from the output stage, again especially under heavier loads. The amplifier channels of the SR7012 share two circuit boards, five channels on one board and four on the other. The individual boards of the SR8012 should enable better cooling of the amplifier channels.
The individual amplifier boards of the SR8012 are cooled by four fans if loads become really heavy. The SR7012 has two fans. The heat sinks of the SR8012 are widely separated. This should provide better cooling than the SR7012 heat sinks that are very close together. Transformers become hotter under load, which in turn increases the resistance of their copper windings and reduces capacity. The toroidal unit of the SR8012 should be more efficient than the EI unit of the SR7012 and thus generate less heat. The SR8012 transformer also appears to be in a more open space that likely will provide for better cooling.
The SR8012 costs more than the SR7012. This added cost appears to at least part go to purchasing higher quality analog circuitry both in the preamp and power amplifier outputs.