Bryston 4B Solid State Stereo Amplifier 250W


A vintage 4B amplifier that is still found in many recording studios today.  

In perfect working condition and checked thoroughly in our lab where it passed with flying colors. 

A few light scuffs here and there - but nothing significant.  

Can be run in Mono for 500W.  

Click here for Stereophile's original 1992 review of this amplifier

PDF copy of the Operating Instructions

PDF copy of the Technical Data and Schematics 


Description: Solid-state stereo power amplifier. Output power: 250W continuous into 8 ohms (24dBW), 400Wpc rms continuous into 4 ohms (23dBW); 800W continuous into 8 ohms in bridged mode (29dBW). Current delivery: 16A continuous, 48A peak, per channel. Frequency response: 1Hz–100kHz, ±3dB for 1W output. S/N Ratio: hum and noise, 108dB below rated output, 90dB IHF. Input sensitivity: 1.4V for 250Wpc into 8 ohms. Voltage gain: 30dB. THD+noise: 20Hz–20kHz, 0.01%. IM distortion (60Hz+7kHz, 4:1, SMPTE method): less than 0.01% at rated power. Damping factor: greater than 500 at 20Hz, at 8 ohms (equivalent to an output impedance of less than 0.016 ohms). Input impedance: 50k ohms unbalanced, 30k ohms balanced. Polarity: non-inverting.

Dimensions: 16 3/16" (411mm) W by 7 1/8" (181mm) H by 13½" (343mm) D.

Weight: 40.1 lbs (20.2kg) net.

Price: $2095, $2295 with optional LED display; TXH-approved version costs $2245 (1992); $2397 (4B-ST, 1999); $3550 (4B-SST, 2007). Approximate number of dealers: 70 (1992); 200 (2007).

Manufacturer: Bryston Limited, P.O. Box 2170, 677 Neal Drive, Peterborough, Ontario K9J 7Y4, Canada. Tel: (705) 742-5325. Fax: (705) 742-0882. US: Bryston Service USA, 30 Coventry Street, Newport, VT 05855. Tel: (802) 334-1201. Fax: (802) 334-6658. Web:

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.



Original Box







Yes - Power

Physical Condition


Working Condition


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