Yamaha R-S700 Stereo Receiver


Design of the Yamaha R-S700 Stereo Receiver

The R-S700 is almost a throwback to another era. Aesthetically, it looks like a standard black receiver. Up close though, its simplicity reminds me of the old stereo integrated amplifier my father had when I was growing up. It has knobs for bass, treble, and balance, as well as a loudness adjustment. It has a record-out selector dial, a source select dial, an A/B speaker switch, and a headphones jack. Revealing it's true modern roots though, are the Pure Direct and CD Direct Amp buttons for minimal processing, and the Sirius satellite radio logo.

Around back, the simplicity compared to surround sound AVRs continues. There are only four pairs of binding posts, two each for speakers A & B. There are four pairs of analog audio inputs, as well as some outputs: subwoofer, zone2 pre-out and main-in/out for external amplification. There is also a 12V trigger out for your external amplification. Analog buffs will delight in the inclusion of a turntable phono-jack input and grounding terminal. The phono jack is compatible with MM type cartridges. Again exposing the modern design are the SIRIUS jack, the iPod dock input, and a composite video output for iPod video from the dock. One surprise to this reviewer was the lack of any digital audio input for a CD transport. The only way to hook up your CD player is via analog stereo RCA cables. This obviously simplifies things a bit, as you don't need to worry if the R-S700 will accept and decode your SACD, DVD-A, HDCD, or Blu-Ray audio via bit-stream or PCM or how or if, it will down-sample the signal. Analog inputs only! If your player has analog outs, the R-S700 can utilize it.

Two features worth mentioning up front (that will get further attention later as well) are the CD Direct Amp switch and the Pure Direct switch. The Pure Direct mode routes signals directly to the amplifier section, bypassing any processing. The CD Direct Amp mode goes a step further by creating a balanced signal from the input source to send directly to the amplifier.

From the owner's manual:

Generates a normal phase and reverse phase signal for both the left and right channels from the input signal and uses the four electronic volumes to send a balanced signal to the amplifying circuit. This feature provides clearer sound as a result of:

  • Improved Signal-to-noise Ratio
  • External Noise Canceling
  • Reduced Distortion

Use of either of these switches disables use of zone 2 speakers, as well as the bass, treble, balance, and loudness controls. This CD Direct Amp feature is intriguing, but the skeptic in me cried "fat chance!" when I read this entry in the manual. My ears would have to be the judge.

Some other design features of note were the uncommonly high damping factor of 240, and the pre-out/main-in coupler jacks. The coupler jacks allow the user to either hook up an external processor and use the R-S700 for its amps only, or to hook up external amplification and use the R-S700 as a pre-amp/processor only. I did not explore either option but it sure is nice to have these options.

As for the damping factor for the amplifier section, the manual states a damping factor of 240, rated at 1 kHz and 8 Ohm. Yamaha informed me (and indeed their website agrees) that this is actually the "Linear Damping Factor". Why linear? Damping factor is simply the ratio of the speaker's input impedance to the amplifier's internal impedance. For a given speaker impedance, (say 8 Ohm) the lower the amplifier's impedance is, the higher the damping factor. However, the input impedance of a speaker varies across the audible spectrum, which is why speakers are given a "nominal" impedance value. So, the damping factor would vary across the audible spectrum as well. A "linear" damping factor implies that the damping factor is either constant across the 20-20,000 Hz range, or that it never drops below a certain value. Indeed the damping factor for the R-S700 is rated at "240 or more". Supposedly, a higher damping factor means the amp has more control over the physical inertia of the speaker driver. I've never personally put much weight (no pun intended) on an amp's damping factor being a significant contributor to overall sound quality of an amplifier. It is one of many specs that can influence the sound. Higher is generally better, in theory. But it can be too high also. Is a damping factor of 240 too high? No, probably not. Is it higher than normal? Well that depends on what you call "normal". The Yamaha RX-A2000 surround receiver I just reviewed had a (linear?) damping factor of 150 and I really liked the sound from that receiver. Does the higher damping factor of this receiver mean I'll definitely like the sound better? No, it definitely does not mean that. There are many factors that can influence the sound. I'm happy to see a high damping factor, just as I'm happy to see higher power in the amps, and a high current power supply, large heat sinks, big capacitors, etc. In the end what matters is how I feel when I sit down in my living room and listen to my favorite music from this receiver, which I'll write about later in this review.

The R-S700 includes two remote controls, one for each zone. The zone 2 remote is much smaller and IR-only. This inclusion of a zone2 remote is very common with receivers these days. I guess A/V companies expect that everyone with multiple zones in their house will have IR repeaters as well. I don't, so the extra remote was useless to me, as the main remote can control either zone. There was a time when some devices came with a UHF remote and a UHF receiver built in to the main unit (I had a Dish TV box like this) which would allow you to control the unit with the remote from almost anywhere in the house. Including a UHF stage in an analog stereo receiver might not be the best idea. However, these days with Bluetooth technology, as well as Wi-Fi, it really seems strange to include a second-zone remote that is IR only. If you happen to have an IR repeater, the second remote may be useful to you. If not, it's a wasted part.

The main remote itself is decent, but not great. The buttons are kind of small, the body is not ergonomic at all, and there isn't any sort of back lighting or night-glow on any of the keys. Granted, this is primarily an audio-only device so it might not be used in the dark as much as a surround processor, but I often find myself listening to music in dimmed or indirect lighting. The buttons and text are so small it's hard to read what's what without direct light. The range of the remote is acceptable (works farther away than one can read the main unit's display), and the buttons, though small, work well. Programming the remote to operate my Sony DVD player was simple enough, and allowed basic control of the Sony's transport functions.

The R-S700 is a hefty receiver, considering it is a stereo only device. I've reviewed surround sound receivers that weigh less than the R-S700. A peak through the top grille reveals a nicely laid out interior with two large capacitors and two very nice looking solid aluminum heat sinks. Yamaha's ToP-ART design (Total Performance Anti-Resonance Technology) is apparent in the symmetric layout of the components inside the R-S700. Yamaha claim that this symmetric design allows "accurate sound field reproduction." In my opinion, this is like having polished chrome headers on your 454 big-block: it may or may not improve performance, but it sure looks nice under the hood. And who among us doesn't want nice-looking HT gear? The "ART" part of the "ToP-ART" moniker refers to Yamaha's chassis design that they claim eliminates effects of external vibration. I'm not convinced that a normal level of external vibration really affects solid-state electronics. Maybe this is why Yamaha is able to claim to have completely eliminated these effects with a bit of chassis reinforcement. Regardless of the marketing spin on the technology and design within the Yamaha R-S700, the proof is in the pudding, so let's see how this baby performed.