Accuphase AD-2850 Phono Stage Board

Details

Specifications

Phono Equaliser Unit.

AD-2850 is the dedicated phono equalizer unit. Analog records can be reproduced with high quality by installing AD-2850 in a rear-panel slot. The AD-2850 features separate input circuitry for MC and MM cartridges to ensure optimum matching and realize outstanding S/N ratio. 2 sets of analog-player input jacks, the AD1 and AD2 are equipped, and their selections are switchable with the INPUT selector of pre-amplifiers.

The AD-2850 uses printed circuit boards made from glass cloth fluorocarbon resin, housed in a sturdy aluminium enclosure to minimise any kind of external influence. The input terminals are connected to the amplification circuitry by the shortest possible route, realising outstanding signal/noise ratio. The use of a DIN standard connector for the link to the host component provides enhanced reliability.

Features

Differential amplifier circuit with ultra low noise bipolar-transistors for MC cartridges.
Differential amplifier circuit with ultra low noise junction-FET for MM cartridges.
Differential RIAA equalizer circuit is designed to provide super accurate RIAA equalization characteristics.
MC Load settings are selectable from among 4 values “10Ω/30Ω/100Ω/300Ω”. The input impedance for both MM settings is 47kΩ.
Storing separate MC Load and/or AD GAIN settings for each installed AD input (AD1 and/or AD2) is available, and it enables the smooth switching of 2 kinds of analog players or tone arms.
The printed circuits are made from glass cloth fluorocarbon resin.

Frequency response

MM/40dB, MC: 20～20,000Hz ±0.2dB
MM/30dB: 20～20,000Hz ±0.3dB

AD maximum input voltage (1 kHz, 0.005% THD)

MM/30dB INPUT: 310mV
MM/40dB INPUT: 96.5mV
MC/60dB INPUT: 9.5mV
MC/70dB INPUT: 3.2mV

Gain (Gain selector set to 18 dB position, 12/18/24 dB settings available)

AD[MM:30/40dB]INPUT → BALANCED/LINE OUTPUT: 48/58dB
AD[MM:30/40dB]INPUT → REC OUTPUT: 30/40dB
AD[MC:60/70dB]INPUT → BALANCED/LINE OUTPUT: 78/88dB
AD[MC:60/70dB]INPUT → REC OUTPUT: 60/70dB

Input sensitivity and impedance

Input, Input Sensitivity (For Rated Output/For 0.5V Output), Input Impedance
AD-MM/30 dB INPUT, 8.0 mV, 2.0 mV, 47 kilohms
AD-MM/40 dB INPUT, 2.5 mV, 0.63 mV, 47 kilohms
AD-MC/60 dB INPUT, 0.25 mV, 0.063 mV, 10/30/100/300 ohms, switchable
AD-MC/70 dB INPUT, 0.08 mV, 0.02 mV, 10/30/100/300 ohms, switchable
BALANCED/LINE, 252 mV, 63 mV, 40/20 kilohms, switchable

Signal-to-Noise Ratio
Input, Input shorted (A weighting) S/N ratio at rated output, EIA S/N

AD-MM/30 dB INPUT, 94 dB, 86 dB
AD-MM/40 dB INPUT, 85 dB, 86 dB
AD-MC/60 dB INPUT, 80 dB, 86 dB
AD-MC/70 dB INPUT, 73 dB, 87 dB
BALANCED/LINE, 111 dB, 110 dB