I routinely rebuild Carver C9 'Sonic Holographic' units. They are useful for some recordings that are multi-miked. This has been non-profit and a sort of hobby for me for 4 1/2 years. At the moment, I have 6 of these units for sale, ranging from $140-260. There are different options available when it comes to circuit upgrades,etc. I will post a photo here, but the rest are at US Audio Mart.