The ultimate: by far the finest integrated amplifier that Pioneer ever made and arguably Pioneer's finest amplifier of any kind. It's a pure class A design--no sliding bias or other tricks, just simple, well designed and well built circuitry, massive heatsinks, a huge power supply, and absolutely breathtaking sound. I have never heard another integrated amp that comes close. Well, maybe Pass Labs--but they cost far more and can't match the A-09 in terms of design.
This unit was serviced about a year ago—it wasn't broken, but I wanted the speaker terminals replaced with gold-plated terminals that accept the spades I use. The tech had plastic mounting plates custom made to fit the rear plate, with great results--see the photos! He also cleaned all inputs and switches, as well the connections between the boards, and adjusted the DC offset and bias current.
Specs:
Rated power: 35W avg power into 8 ohms, 70 into 4 ohms (Max around 50W into 8 ohms/90W into 4 ohms)
Type: Class A all the way to 36W avg into 8 ohms
Inputs: stereo RCA, balanced XLR
Years of manufacture: 1992-1996
Weight: 28.8kg
Voltage: 100V for use in Japan. A step-down transformer for use in the U.S. will be included for an additional $30—please message me if interested.
Condition: quite beautiful, no major dents or scratches, but there are some minor scratches/nicks in a few places, so please see the photos to judge for yourself. There is one little scratch on one of the top plates, one near the front on one side, and a few nicks/dots on the front panel--I can't see them except at close range.
Accessories: the user manual and a little card explaining the phono stage (all in Japanese) are included. I believe they may be photocopies made by the shop where I bought the unit. A 500 watt step-down transformer to allow for use with US outlets will also be included for an additional $30--please message me if interested.
Shipping: the unit will be packed professionally, double boxed, and fully insured. The step-up transformer will be shipped separately in its original box. Local pickup is also available in Boston, MA.
Please contact me for a quote if you're interested in international shipping--it may be cheaper than Ebay's calculation!
More info about the A-09:
All of the top Japanese companies produced signature integrated amps in the early 1990s. Pioneer's offering, the A-09, was first and best–and was recognized as such in the European and Japanese press. It's conservatively rated at 35 watts per channel into 8 ohms and 70 into 4 ohms, and it's capable of delivering 140 watts of dynamic power into 2 ohms. This is certainly not a high wattage amp and works best with reasonably sensitive speakers. But it doesn't *sound* like a low wattage amp because it has a high damping factor and high current capability, so even when operated near the full rated power it doesn't struggle to put out power into low impedances. I use it with a pair of Martin Logans that reach an impedance of just 1 ohm in the high frequencies and the sound is fuller and more powerful than with a 200 watt per channel M91 power amp!
The A-09's design is symmetrical and fully dual mono, with the voltage and power amp separated, fed by independent banks of filter caps. Thanks to Pioneer's "Super Linear Circuit" design (inherited here from the Exclusive M6), no negative feedback whatsoever is utilized in the power amp. The preamp stages, meanwhile, are housed in an aluminum-and-copper box within a box that's insulated via rubber strips from vibrations. Only three controls are present: input and rec selection knobs, which trigger relays located right next to the rear inputs, and volume, which turns a long brass shaft leading to a handmade attenuator--the same one used in the famed Exclusive C7.
The effort that went into perfecting each aspect of this amp is extraordinary. The entire layout is designed to achieve the shortest possible signal paths, eliminate interference from noisy elements like the power supply and output transistors, and ensure that the left/right channels are completely independent and identical with regard to temperature and vibration. The heatsinks are huge and a unique design—the extra thick spine allows all of the transistors to sit right at the back, keeping the signal path short and pulling heat away toward the front where it's dissipated by fins of varying lengths (to reduce resonances, according to Pioneer). Copper shielding is everywhere: around the power transformer as well as the transistors and most electrolytic capacitors. All of the big filter caps (90,000 micro farads in total) are Pioneer-made, as is the transformer (a custom ultra low-flux design)—both designed solely for use in this model.
Knobs are solid aluminum, fuses are special audio-grade, internal wiring is heavy gauge and shielded in a custom Pioneer design. Relays are sealed, and the output/protection relays are located outside of the signal path to avoid any degradation! The power cord is heavy gauge, well shielded, and enters the transformer directly from the bottom of the unit to avoid interference. The chassis is special too: brushed aluminum on all sides, set on a base of specially insulating Pioneer-developed resin (the same stuff used in the M7 and C7); the feet are solid resin as well.
The FET phono stage is excellent, though note that it takes moving magnet cartridges only. It powers off when not in use, again to avoid interference. A pair of true balanced inputs are included as well; I used them with my DAC with great results.