best preamp under 4000 to match 4b sst

A few questions for you first:

Is your budget $4,000?
(I assume you mean USD, or is that in Euros?)

Do you prefer new or used?

Do you want tubes or do you prefer solid state?

Do you need just a line stage, or do you need a full function preamp? (i.e. one with a phono stage)

Is a remote a requirement?

If you don't need a phone stage, the Dodd Battery pre, and $2,500 new is a wonderful preamp, and especially well suited to SS amps due to its low output impedance for a tube preamp. Being battery powered it is extremely quiet, almost like a passive. Worth exploring.

The 4B SST has fairly low input impedance (50 Kohm single ended/ 20kOhm
balanced), so using a SS preamp, or a tube preamp with low output
impedance
is going to be best.

Just about any SS preamp will work. I'd look at Bryston (for obvious reasons),
Klyne, Classe and Pass Labs.

For tube preamps, consider: Audio Horizons TP2.1, Modwright SWL9.0SE or
36.5, Lamm LL2 Deluxe, Atma-Sphere MP-3, First Sound Presence Deluxe II.
Basically, I believe you'll be best served with a tube preamp with output
impedance of 600 ohms or lower (lower is better in the case of the 4B SST,
IMO).

I once used a First Sound Presence Deluxe II with a Bryston 4B SST with
excellent results. My favorite tube preamp in your budget range is the Lamm
LL2 Deluxe. The impedance match looks good on paper, but I've never heard
the combo.

The Atma-Sphere MP-3, Lamm LL2 Deluxe and First Sound Presence Deluxe
II do not have remote control. The Audio Horizons TP2.1 has an optional
remote control. Both Modwright preamps have remote control.