The Analog Tone Factory own a special custom all tube Ampex 351 tape machine. This Ampex 351 was painstakingly revised, modified and converted to half inch 15/30 ips operation for absolute best sound quality by some of the best technicians in the US, a process which took over two years. We wanted to get closer to the sound of the great recordings of the fifties and sixties when the Ampex 351 was the machine of choice, and also have the better quality and lower noise floor of half inch operation at 30 ips.