in perfect working condition, just serviced
Accuphase C280L Pre-amp
One of the finest pre-amps ever built
Here are the distinguishing features;
Most amplifiers with balanced inputs convert to non-balanced operation inside. This pre-amp has fully balanced line pre-amps from input to output. Even the volume control is controlled by a precision 4-channel volume (linked to LR channel) which is completely divided into hot and cold for balanced operation.
Class A, low feedback
All circuits are biased in push-pull Class A and rely on cascode connections for low NFB amounts and high-frequency linearity. A FET is used in the load side of the cascode-connected amplifier, so that there is no need to worry about base current leakage when using a bipolar transistor.
The phono sections is a three-stage cascode (first stage in p-p differential, the other two in p-p), DC-Servo is applied in all stages
Hi-end Power Supply
The power supply section has a dedicated power transformer for the left and right channels, making it a completely independent electrical and structural mono-construction. Six constant-voltage power-supplies coming out of each transformer and feeding each of the six modules - that's 36 separate power-supplies !
The bank of caps holds six 16V/22,000µF ELNA For Audio -per channel- for an astounding total of 264,000µF.
Hi-end switching by sealed nitrogen gas relays
Switching by sealed nitrogen gas relays, which were developed especially for audio and communication equipment are used. The contact is a crossbar twin system of gold and silver-palladium alloy. This is the purest from of switching and has ten times less distortion than commonly used solid-state switching. It also has the highest durability.
In order to improve reliability, four circuits are used in parallel for the low-level signal path for completeness.
Frequency response: 1Hz to 350kHz
Total harmonic distortion: 0.005%
Gain: 86dB (MC), 54dB (MM), 18dB (line)
Input sensitivity: 0.05mV (MC), 2mV (MM), 126mV (line)
Signal to noise ratio: 72dB (MC), 90dB (MM), 115dB (line)
Output: 126mV (line), 2V (Pre out), 10V (Pre out Max)
Semiconductors: 219 x transistors, 58 x FET, 26 x IC, 174 x diodes
Dimensions: 468 x 171 x 396mm
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