There is a constant hum on channels 1 and 2 with and without an input; due to the corrosion present I believe this issue is probably within the Bose EQ card. The input signal passes through and is amplified as expected.
eBay
Digital Power Amplifier 2/4 Channel Professional Amplifier Karaoke Audio Power Amplifier For KTV
Aliexpress UK
Samson SX-2800 Power Amplifier. In great working order! The Samson SX2800 stereo power amplifier has been designed to provide robust, clean output with low distortion and wide dynamic range, along with the dependability demanded by professional audio engineers and installers.
eBay
A1S Pure Class A Amplifier 20W Pure Class A Power Amplifier Home HIFI Fever Level Power Amplifier 4-8Q
Aliexpress UK
eBay
T7 Dual Channel Pure Post-level Power Amplifier Using Berlin Voice 909 Power Amplifier Circuit fully symmetrical X-Amp Circuit
Aliexpress UK
The Cloud VTX 750 is a. This rack-mountable unit has a 10Hz-40kHz frequency response with 0.03% typical distortion, and includes features like per-channel 65Hz high-pass filters, bridge mode, and remote monitoring capabilities with the optional VTX-WM1 web monitor card, notes Cloud Electronics and Canford Audio.
eBay
12V 220V 800W Car Hifi Power Amplifier Bluetooth 5.0 Amplifier Mini HIFI Digital Bluetooth Audio Power Amplifier 2.0 Channel
Aliexpress UK
Fully working. All inputs and outputs are fully working. A very nice unit and plenty of power.
eBay
AK380/370/350 800W 12V HiFi Power Amplifier Home Karaoke Car Audio Power Amplifier Stereo BASS Speaker Class D Home Sound Amp
Aliexpress UK
UNIT IS IN USED CONDITION. TESTED & WORKING. POWER CABLE INCLUDED. EXCELLENT HIGH QUALITY POWER AMP. AMAZING SOUND. GOOD WORKING ORDER. COSMETICALLY SOME RUBS / LIGHT SIGNS OF USE. CONSULT PHOTOS FOR EXACT ITEM YOU WILL RECEIVE. TESTED & WORKING.
eBay
TZT Transaudio T9.4 450W/4Ω Class AB Amplifier Power Amp Audiophile-Grade Power Amplifier (110V/220V Silver)
Aliexpress UK
item is in good conditon. very minor wear and tear. item has been tested and is in fully working order. comes with no power cable. Any Questions Feel Free To Ask.
eBay
HiFiAMP Transaudio T9.4 450W/4Ω Class AB Amplifier Power Amp Audiophile-Grade Power Amplifier 110V 220V
Aliexpress UK
I do not know how to fix it hence why listed as parts.
eBay
Class A Gold Sealed Tube Headphone Power Amplifier 4.4mm Balanced Output 2000mW Power Desktop Headphone Amplifier MUSE02 Op Amp
Aliexpress UK