Channel mixing headphone amplifier

KA71 is a stereo headphone amplifier with additional function of stereo channels crossmixing. As such it is designed for Amiga computers. Amiga sound chip Paula sends two of its four audio channels to stereo left channel, two to the right channel. They are fully separated, which is annoying especially when listening with headphones. KA71 can mix stereo channels at a level adjustable with a knob, from full separation to mono output. It can be also used with computers having monophonic audio, or to mix two computers simultaneously playing parts of the same song. Of course one can also use KA71 as a regular headphone amplifier with smartphones, music players, computers and other sources.

WARNING: KA71 amplifier, depending on input signal, connected headphones and volume set, can produce sound pressure levels higher than 85 dB. High sound pressure level is harmful and may cause irrecoverable damages to your hearing sense. 85 dB is considered safe for continuous listening. Be careful turning the volume up and switch off the amplifier when changing signal sources!

Features

• Freely adjustable stereo channels crossmixing from pass through to full mono.
• Can be used as mixer/pre-amp for a loudspeaker power amplifier or active loudspeakers.
• High output power, able to drive high-impedance phones.
• High audio quality, low distortions, low noise, wide bandwidth (10 Hz to 30 kHz).
• May be powered either via micro USB socket (from computer, USB hub, phone charger, powerbank), or 3 AAA batteries (one use or rechargeable).
• Batteries need not to be removed when using USB power, they are disconnected automatically.
• Selected high quality components. Only polyester and HQ aluminum electrolytic capacitors in the audio path.
• Modern design using mostly SMD parts.
• Durable aluminum encolsure.