Check the listing for details. SAMSON QH4 4-Channel Stereo DJ Studio Monitoring Headphone Amplifier Amp. Condition: Used. Listed at 40.00 USD. no power adapter included. tested working Experience high-quality sound with the Samson QH4 4-Channel Stereo DJ Studio Monitoring Headphone Amplifier Amp. This amplifier is perfect for those in the music industry, especially for those who want to have multiple headphones connected to one output. The QH4 has four headphone outputs, each with their own volume control, allowing you to have individual and customized sound for each listener. Not only does this amplifier offer great sound quality, but it is also compact and portable, making it easy to take with you on the go. Its sturdy design ensures that it can withstand the wear and tear of everyday use. Get your hands on the Samson QH4 and take your listening experience to the next level.