Amazon.com: Sennheiser GSX 1000 Gaming Audio Amplifier, 7.1 Surround Sound, PC and MAC, Gaming DAC and EQ, for W with Sennheiser PCV 05 Combo Audio Adapter : Video Games
Sennheiser GSX 1000 7.1 Channel Amplifier for sale online | eBay
GSX 1000 Audio Amplifier: headphone amplifier for gamers - The Audiophile Man