Classic and built to last, this Yamaha A-S2000 Integrated Amplifier is one hell of an amplifier in very good physical and working condition. Fully balanced design with both XLR and RCA inputs. Includes a great MC, MM phono stage and headphone amp built in. Sounds more powerful than the 90watts/channel. I have all the original packaging and remote. From the Manufacturer:
The Yamaha A-S2000 Stereo Amplifier: The Most Natural Sound Imaginable
Yamaha introduces a new, superior approach to analogue amplifier design. Find out what's really possible from your hi-fi components with Yamaha's most innovative amplifier design yet. Heat sink Huge power transformer Custom-made block capacitors Preamp board
Full Floating and Balanced Circuit Design Achieves for the First Time the Full Potential of Analogue Amplification
More that forty years have passed since the introduction and widespread adoption of full transistor HiFi audio amps during the 1960s. In the 1970s, high performance, high output PNP-NPN transistors made possible the pure complementary configured power amps that are now the main type of high quality audio amps. In recent years, however, digital amps have become popular for their high conversion efficiency and superior uniformity of operating precision, as well as for their lower weight, size, and heat production as compared to analogue amps. Which leads to the question, which direction will audiophile-level amps take in the future? Some manufacturers of audiophile-quality amps try to improve the traditional pure complementary analogue amplifier, while others are seeking to achieve higher sound quality from digital amplifiers.
But Yamaha has developed a third, superior approach. This is an entirely new floating and balanced power amp that, by using power transistors with the same polarity that are not complementary, achieves complete symmetry of pullable operation at the output stage and permits full balanced transmission (amplification) from the input jack to just before the speaker jack--a capability that has long been the dream of audiophiles.
How Does the Floating Balanced Amplifier Design Work? Completely symmetrical construction
with integrated amp left-right separation
View back panel
Floating Balanced Power Amp
The Floating Balanced Power Amp configuration is completely different from the pure complementary circuit design that has been the mainstream of HiFi amps for nearly 40 years. It adopts an output element having identical polarity on the plus and minus sides of the output stage, with both sides having their own power supply and feedback, thereby achieving total symmetry of pullable operation at the output stage. The power supply unit has four floating elements (no restrictive grounding connections), two for each channel, so plus and minus are completely symmetrical.
Full Stage Balanced Signal Transmission
The A-S2000 achieves fully balanced signal transmission from input to output (balanced design refers to the use of two signal conductors that have equal impedances to the ground). Balanced transmission is capable of canceling noise produced internally and externally, and so is considered to be an ideal amplification method, eliminating the sound quality degradation caused by noise. If it is only partially adopted, however, it will be largely ineffective and may even have negative effects. The A-S2000 is the world's first integrated amp to offer full-stage balanced transmission, combining high power output with good sound texture and outstanding signal-to-noise performance. Its capabilities will be heard to best effect when paired with the Yamaha CD-S2000 Super Audio CD player, which employs the same principle.
Fully Balanced Amp Control
To achieve fully balanced transmission, all audio circuits except for the phono equalizer are balanced. The line amp also uses a balanced configuration for its volume and tone circuits, achieving fully balanced transmission from the XLR balanced input jack to just before the speaker jack. Additionally, the output from the unbalanced RCA input and phono equalizer undergoes balance conversion internally.
Parallel Volume and Tone Controls
To ensure ideal fully balanced operation, the volume and tone control systems must be extremely precise. Conventional analogue volume systems suffer from gang error, and cannot achieve sufficient accuracy, even when using high precision parts. Therefore, for the A-S2000 we developed a unique method: canceling out slight precision differences by the parallel operation of three high sound quality digital volume ICs for each channel and operating the system with an analogue encoder. When using the bass and treble tone controls, each of the three volume elements is applied in succession, and during tone default, three equivalent volume elements for each channel are used for volume adjustment. This ensures the best sound quality during both tone control and default operation.
Power Supply That Cleans Itself
The A-S2000 has four large capacity power supplies for the power amp that are completely isolated from ground. Shunt type local regulators that prevent degradation of sound quality by amperage fluctuation ensure a clean and stable power supply for the preamp, so you won't get any "line noise" from a dirty power source. Naturally, parts that directly affect sound quality such as the large power supply transformer and carbon sheath block capacitors were chosen only after careful evaluation.
Symmetrical Construction Mimics the Benefits of Having Separate Amps
The A-S2000 has a completely symmetrical construction intended to achieve the ultimate in integrated amp left-right separation, equal to that of separate amps. A central reinforcing bar ensures that the chassis is rigid and stable.
Specially Designed Feet Dampen Noise Vibration
The extra-heavy feet provide a choice of two bases. You can leave the round, flat neodymium magnets in place or remove them to rest the amplifier on four single points. The feet are also height adjustable. They ensure stability on any surface, with superior vibration damping.
Headphone Amp for Low Impedance Drive
The fully discrete, high performance headphone amp is compatible with low impedance drive. Its pure and powerful sound quality is best appreciated with high quality headphones.
Discrete Phono Amp
An extremely low-noise phono amp plus a dedicated MC head amp ensure excellent musical clarity and imaging with both MC and MM phono cartridges.
- Minimum RMS Output Power
- (8 ohms, 20Hz--20kHz): 90W + 90W
- (4 ohms, 20Hz--20kHz): 150W + 150W
- Maximum Power
- (8 ohms, 1kHz): 120W + 120W
- (4 ohms, 1kHz): 190W + 190W
- Dynamic Power/Channel (8/6/4/2 ohms): 105/135/190/220W
- Frequency Response
- CD, etc. to Speaker Out, Flat Position: 5Hz--100kHz, +0dB / -3dB
- CD, etc. to Speaker Out, Flat Position: 20Hz--20kHz, +0dB / -0.3dB
- RIAA Equalization Deviation
- Phono MM: 20Hz--20kHz, +/- 0.5dB
- Phono MC: 20Hz--20kHz, +/- 0.5dB
- Total Harmonic Distortion
- CD Balanced to Speaker Out: 0.01% (90W / 8 ohms)
- CD, etc. to Speaker Out: 0.015% (90W / 8 ohms)
- Phono MM to Rec Out: 0.005% (2V)
- Phono MC to Rec Out: 0.05% (2V)
- Audio Muting: -20dB (approx.)
- Load Impedance
- Speaker A or B: 4 ohms to 16 ohms
- Speaker A + B: 8 ohms to 16 ohms
- Dimensions (WxHxD): 17-1/8" x 5-3/8" x 18-5/16"
- Weight: 50 lbs