If you go with a balanced preamp, it will help if it supports the low impedance (600 ohm) balanced line standard. This will reduce the effects of the interconnect cable dramatically, and free you to have the cables as long as you want.
There are very few tube preamps that support this standard (without frequency response problems). The traditional way that tubes have driven 600 ohms in the past is with an output transformer, but the transformer can be a barrier to transparency. Direct-coupling is the only way I know to get around this.
There are very few tube preamps that support this standard (without frequency response problems). The traditional way that tubes have driven 600 ohms in the past is with an output transformer, but the transformer can be a barrier to transparency. Direct-coupling is the only way I know to get around this.