Responses will depend upon which Rowland amp you have.
Early Rowland amps used the 600 Ohm balanced input impedence standard and won't work well with some tube preamps.
The 6/8ti/9ti, the 10/12, and the 300 series amps are transparent and resolving -- they demand quality preamplification. These amps are fully differential balanced and benefit from a balanced preamp (that's one reason the top ARC amps work well with them).
The 201/501's are more forgiving of partner components.
I used two single-ended preamps with Model 6's, a Hovland with the amp switched to the higher impedence setting (18 Khz.), and an ARC LS-3, with the impedence set to the standard 600 Ohms. Both set ups were great.
Early Rowland amps used the 600 Ohm balanced input impedence standard and won't work well with some tube preamps.
The 6/8ti/9ti, the 10/12, and the 300 series amps are transparent and resolving -- they demand quality preamplification. These amps are fully differential balanced and benefit from a balanced preamp (that's one reason the top ARC amps work well with them).
The 201/501's are more forgiving of partner components.
I used two single-ended preamps with Model 6's, a Hovland with the amp switched to the higher impedence setting (18 Khz.), and an ARC LS-3, with the impedence set to the standard 600 Ohms. Both set ups were great.