BHK Signature 300 Mono

PS Audio BHK 300 sig mono

Power Amplifier

Midland HiFi Studio - Key Information

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Overview & Features

Only a rare handful of power amplifiers withstand the test of time. The BHK Signature 300 is one such amplifier. Hand built, uncompromising.

The BHK Signature 300 Mono power amplifier culminates one man’s lifelong quest for perfection in power amplification. Bascom H. King’s magnum opus combines a pair of vacuum tubes on its input with a double set of parallel MOSFET outputs capable of 300 watts in 8Ω, 600 into 4Ω and more than 1,000 watts into 2Ω.  The BHK Signature 300 amplifier can drive any loudspeaker to musical perfection and is the most important element in your music reproduction chain.


Zero-loss parallel vacuum tube input stage

Fully paralleled inside (not like a traditional bridged approach)

Differentially coupled, paralleled, balanced MOSFET output stage

All through hole construction (no surface mount parts)

RCA Single ended input

XLR balanced input

300 watts 8Ω

600 watts 4Ω

1000 watts 2Ω

Less than 0.1% thd 20Hz to 20kHz at rated power

Damping factor 100 for excellent loudspeaker control

Front panel standby button for vacuum tube input

-3dB greater than 200kHz

Dual, custom, solid copper, gold plated output binding posts

Fully balanced from input to output

83 pounds

Input 12 volt trigger

Easy access for tubes

Technical Specification

Unit Weight

83 lbs [37.6 kg]

Unit Dimensions

17.1” x 8.7” x 14” Chassis only. 15" deep including connectors.

Shipping Weight

92 lbs [41.7 kg]

Shipping Dimensions

21”x 13” x 19”

Color Options



Mains Power Inputs


Fuse Compliment all Countries

4 - 10 amp fast blow H-Rated 5x20mm Rail Fuses

230vac Countries

1 - 1 amp slow blow H-rated 5x20mm

1 - 5 amp slow blow H-rated 5x20mm

Accessories Included

UK (BS 1363) (230V version)

Audio Inputs

RCA (Unbalanced)

XLR (Balanced)

Speaker Outputs

Gold plated copper binding posts (2 pair)


DC Trigger Input

3.5mm 5-15VDC


3 years parts and labor on unit

1 year on vacuum tube

Power Consumption

@Ready - 75 Watts

@Idle - 175 Watts

@Rated power 8Ω - 850 Watts

@Rated power 4Ω - 1600 Watts



30.5dB +/-0.5dB

Sensitivity for rated output power of 250 watts into 8Ω



100-20KHz <-85dBV

Input impedance

Unbalanced:  50KΩ

Balanced:  100KΩ

Output Impedance

50Hz, 2.8VRMS<0.1Ω

Frequency Response@2.8VRMS

10Hz – 20KHz +/- 0.1dB

10Hz – 200KHz +0.1/-3.0dB


1KHz, 1W/8Ω<0.01%

20-20KHz, 1W/8Ω<0.1%

1KHz, 200W/8Ω< 0.1% (120VAC Mains input)

1KHz, 400W/4Ω< 0.1% (120VAC Mains input)

Output Power (Both channels driven 120vac mains, 1kHz, 1% THD)

8Ω:  300W minimum

4Ω:  600W minimum

2Ω:  1000W

Damping factor:  >350