Agree with fsonicsmith re jump factor.
Answering the OP question, I'd say $5k to $20k. In other words, the price of a Shindo preamp.
I would rather go straight from DAC to amp using jriver digital volume control than use a $2k preamp. The big jump, where the preamp adds musicality (and not just warmth) happens above $5k.
Warmth is often just smearing and roll off. Musicality is extra tone, no details smeared away, and extra compelling transients.
Answering the OP question, I'd say $5k to $20k. In other words, the price of a Shindo preamp.
I would rather go straight from DAC to amp using jriver digital volume control than use a $2k preamp. The big jump, where the preamp adds musicality (and not just warmth) happens above $5k.
Warmth is often just smearing and roll off. Musicality is extra tone, no details smeared away, and extra compelling transients.