DESIGN
Nothing in the design of a power amplifier is more important than its input stage when preserving music’s finest nuances. In the BHK Signature, a vacuum tube serves as the perfect interface between the preamplifier and MOSFET output stage. This hybrid approach offers stunning musical performance and unrivaled, effortless drive to the speaker. The Signature 250 Stereo Amplifier is the ultimate choice when a single chassis solution is required.
APPLICATION
The BHK Signature 250 Stereo Amplifier produces 250 watts/ channel into an eight-Ohm loudspeaker, 500 watts/channel into four-Ohms, and stable into 2-Ohms; enough power to satisfy even the hungriest of loads. Use this amplifier as the bedrock of your high-performance audio or home theater system. The BHK 250 provides the finest performance, reliability and build quality possible, in a single chassis format.
INPUT STAGE
A power amplifier’s input stage is a critical interface in the quest to preserve music’s essential details and vacuum tubes do it best. Hand matched pairs of Russian Gold Lion 6922s provide the perfect interface between the delicate musical transitions output by the DAC or preamplifier, transferring it without loss to the MOSFET output power stage and eventually the loudspeakers. The hybrid approach used in the BHK Signature takes advantage of the best traits technology has to offer, unavailable in traditional solid state or tube designs. While vacuum tubes are the perfect input stage, they cannot make the same claim on a power amplifier’s output. Conversely, solid state designs are correct for output stages, but suffer when used as inputs. Only a hybrid approach takes advantage of the best in both disciplines.
OUTPUT STAGE
A power amplifier connects its reservoir of energy to the loudspeaker through a type of valve (solid state or vacuum tube) controlled by the input stage. If the input stage has done a good job of preserving music’s subtle details, textures, timing and phase information, transferring it without loss to the power stage and eventually the loudspeakers is best handled by a tube-like solid state device known as a MOSFET. Not all MOSFETs are the same, their differences characterized by their relationship with the input signal and the power supply driving them: N-types for the positive going signals, P-types for negative. N-types have lower distortion and perform better than P-types but N-channel-only amplifiers are rare. Using only N Channel MOSFETS in its output stage, the BHK Signature produces a near-perfect balanced waveform without the degradation inherent in a complementary design.
Features
- ZERO LOSS INPUT TUBE
- POWERFUL MOSFET OUTPUT STAGE
- THROUGH-HOLE CONSTRUCTION
- RCA SINGLE-ENDED INPUT
- XLR “TRUE” BALANCED INPUT
- 250 WATTS PER CHANNEL 8Ω
- 500 WATTS PER CHANNEL 4Ω
- 2Ω STABLE
- -3dB > 200khz
- < 0.1% THD 20Hz – 20kHz AT RATED POWER
- DAMPING FACTOR = 100
- FRONT PANEL STANDBY BUTTON
- BALANCED INPUT TO OUTPUT
- DUAL, COPPER, PLATED, OUTPUT BINDING POSTS
- 83 LBS.
- INPUT 12 VOLT TRIGGER
Specifications
BHK Signature 250 Stereo and BHK Signature 300 Mono |
|
| 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 | Black Silver |
| Voltage Options Factory set only |
Japan 100V North America 120V Europe/Asia/Australia/New Zealand 230V |
| Mains Power Inputs | IEC C14 |
| Fuse Compliment all Countries | 4 – 10 amp fast blow H-Rated 5x20mm Rail Fuses |
| Fuse Compliment Mains | 100vac Countries 1 – 2 amp slow blow H-rated 5x20mm 1 – 12 amp slow blow H-rated 5x20mm 120vac Countries 1 – 2 amp slow blow H-rated 5x20mm 1 – 10 amp slow blow H-rated 5x20mm 230vac Countries 1 – 1.6 amp slow blow H-rated 5x20mm 1 – 5 amp slow blow H-rated 5x20mm |
| Accessories Included | US (NEMA 5-15P) (all versions) Schuko (CEE7/7) (230V version) UK (BS 1363) (230V version) |
| Audio Inputs | RCA (Unbalanced) XLR (Balanced) |
| Speaker Outputs Signature 250 | Gold plated copper binding posts (2 pair per channel) |
| Speaker Outputs Signature 300 | Gold plated copper binding posts (2 pair) |
| Other | DC Trigger Input 3.5mm 5-15VDC |
| Warranty | 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 |
Signal |
|
| Gain | 30.5dB +/-0.5dB |
| Sensitivity for rated output power of 250 watts into 8Ω | 1.3V |
| Noise | 100-20KHz <-85dBV |
| Input impedance Signature 250 stereo | Unbalanced 100KΩ Balanced 200KΩ |
| Input impedance Signature 300 mono | 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 |
THD&IM |
|
| 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) |
Signature 250 Stereo Amplifier |
|
Output Power |
Both channels driven 120vac mains, 1kHz, 1% THD |
| 8Ω | 250W minimum |
| 4Ω | 500W minimum |
| 2Ω | Stable for musical transients |
| Damping factor | >150 |
Signature 300 Mono Amplifier |
|
Output Power |
120vac mains, 1kHz, 1% THD |
| 8Ω | 300W minimum |
| 4Ω | 600W minimum |
| 2Ω | 1000W |
| Damping factor | >350 |
