Adcom GFA-565 Monoblock Amplifiers - Serviced and Ready to Rock!

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These now vintage amps have a huge following, mostly due to their value/performance ratio. They can also drive just about anything without much strain or drama.

AND both amps feature the factory optional and rare balanced XLR input card!

Problem is - they usually need a good amount of work to get another 25 years out of them. We've taken the time to bring them up to speed.

While they're not perfect cosmetically, they are working and sounding perfectly.

Cosmetic Condition:
* Scratches on some surfaces
* Indicator dot on the input selector control does not correspond with the selection due to replacement of that control.
* Some rack mounting hole plugs are missing

Repair Notes:
* Driver cards removed and thoroughly cleaned.
* The majority of the driver card transistors were replaced with modern production equivalents.
* Electrolytic capacitors checked throughout all amp boards. All out of spec parts replaced.

Our Testing Process for Amplifiers (Solid State) at SkyFi:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally, we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If everything reads clean, we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier then remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will be also be tested.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage Kef speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Description:
Solid-state monoblock power amplifier

Specifications:
Rated power output: 300W into 8 ohms (24.8dBW), 450W into 4 ohms (23.5dBW), 850W into 2 ohms (23.3dBW), all 20Hz–20kHz at 0.02% THD
Frequency response: unspecified
Input impedance: 50k ohms
Input sensitivity: 2.15V for rated output
S/N (A-weighted, full output): greater than 106dB
Damping factor: >1000, 8 ohms, 20Hz–20kHz
Dynamic headroom (at 4 ohms): 1.6dB.
Dimensions: 17" W by 8.25" H by 11.5" D

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.