in line amplifier headphones

Group listening amplifiers commonly provide four independent headphone outputs with individual rotary volume controls so each listener can set their own level.

Some amplifiers include multiple selectable gain settings; one example lists four gain positions at 0 dB, 6 dB, 12 dB and 18 dB, while others list single numeric gain values such as 11 dB.

Commercial mixer-amplifiers in this set support traditional low-impedance speaker loads (8 Ω and 4 Ω) and also distributed-audio 70V and 100V systems for installed audio.

Product details show common connectors include 3.5 mm and 6.3/6.35 mm headphone jacks, paired RCA inputs and RCA loop/outputs, and USB-C adapters with built-in DAC/AMPs for USB-C sources.

Product details show a mix of connectivity: paired RCA inputs and RCA loop/outputs, 3.5 mm and 6.35 mm headphone jacks, 1/4" (6.3 mm) TRS headphone outputs on multi‑channel units, RJ45 ports for remote volume control, and balanced mic/line inputs on mixer‑amps.