Denon PMA-S10II (1997)

Name: Denon PMA-S10II
Brand: Denon

The PMA-S10II is a high-end pre-main (integrated) amplifier that Denon released in February 1997 at ¥230,000. It's based on the original PMA-S10 with significant improvements. The biggest one is output power, which doubled from the earlier model's 50W + 50W to 100W + 100W into 8Ω (both channels driven, 20 Hz-20 kHz, 0.07% THD). Into 4Ω it makes 200W + 200W at 1 kHz. Period material describes it as a "legendary high-end integrated amplifier with pure power."

The engineering focus was clean, high-current delivery. Denon used a UHC single push-pull circuit with UHC-MOS transistors. The company claimed these supplied current equal to or better than bipolar transistors while keeping the sonic character of a MOSFET. The power supply is a serious affair. It has a large magnetic-circuit transformer with low magnetic flux density, mounted using an LC system to reduce leakage flux. Independent windings feed the voltage amplifier stage, phono equalizer, and control circuits, so they don't interfere with each other. The amp is a twin monaural design with independent left/right power amp blocks, and a six-block internal structure that separates and shields circuits of different signal levels.

The chassis is 1.6 mm steel, painted in the same black grade as Denon's separate amplifiers. Vibration control got real attention: a laminated transformer mount, sintered-alloy insulators that convert vibration to heat, and a high-damping material attached to the insulators. The speaker terminals are gold-plated machined brass, with an enlarged 6 mm clamp hole for very thick cable. The phono stage has a discrete low-noise FET first stage with its own stabilizing power supply. Denon also raided its S1-series parts bin: a 40-inch 4-channel volume control, large machined gold-plated pin jacks, OFC internal wiring, inert gas-filled relays, high-grade capacitors, and a detachable AC cord.

The PMA-S10II's phono MM RIAA deviation is ±0.3 dB from 20 Hz to 20 kHz, and its line signal-to-noise ratio is 110 dB (A-network, input shorted), figures that speak to the care taken in the analog stages.

The PMA-S10III followed in 2000 at ¥250,000 and inherited the basic structure of the S10II. Used S10II examples have appeared around $1,425 recently, and the instruction manual (PMA-S10II_IM_En.pdf) is available.

**Known specifications:**

- Rated output: 100W + 100W (8Ω, 20 Hz-20 kHz, 0.07% THD)

- Rated output: 200W + 200W (4Ω, 1 kHz, 0.7% THD)

- THD: 0.01% (8Ω, -3dB rated output, 1 kHz)

- Line input sensitivity/impedance: 150 mV / 47kΩ (Source Direct off); 150 mV / 15kΩ (on)

- Phono MM: 2.5 mV / 47kΩ; Phono MC: 0.2 mV / 100Ω

- S/N ratio: 110 dB (line), 91 dB (MM at 5 mV), 78 dB (MC at 0.5 mV)

- Dimensions: 434 × 181 × 485 mm (W×H×D)

- Weight: 30.0 kg

- Power consumption: 300W