Our most esoteric product is THE 300B PREAMPLlFIER. This is the first and only preamp to feature these classic tubes. We had been designing the 300B into small power amps for many years and have always had great respect for the smooth natural sound of this tube. However, a single 300B provides truly appropriate power and voltage swing for headphones and makes a remarkable line driver. Here is where the impedances are not too low and the power requirements are not too high: ideal for this kind of tube in a single-ended configuration. This was the genesis of a new preamp.
Inputs: 5 stereo pair unbalanced RCA jacks
Outputs: 2 stereo pairs MAIN out same as SUB out unbalanced RCA jacks
RECORD output: 1 stereo pair pre-volume control unbalanced RCA jacks
HEADPHONE Outs: 2 front panel 1/4" headphone jacks
Optimized headphone impedance switching: 30-400 Ohms to 300-4000 Ohms
MUTE: Selecting HEADPHONE operation mutes LlNE outputs
Output Vacuum Tubes: 2 x 300B Electro-Harmonix
Input Tubes: 2 x 6SL7GT Russian (Electro-Harmonix or SOVTEK)
Rectifier Tubes: 2 x 5U4GBEH Electro-Harmonix or 5AR4C by Ruby
Regulator Tubes: 2 x OD3 NOS JAN USA
Gain: factory set at 12 dB at max Volume
Internal Variable Feedback: 8.5 dB of global NFB is used 12 dB of gain, adjustable trim -1.7dB to +1dB
Noise Floor: typically -70 dB (1 Hz - 100 KHz)
S/N Ratio: typically 105 dB (A WGT, 20 Hz - 20 KHz)
Frequency Response: 5 Hz to 50 KHz 1dB
Channel-to-Channel Separation (L to R): 1KHz 48 dB - 10KHz 35 dB - 20KHz 34 dB
Channel-to-Channel Separation (R to L): 1KHz 50 dB - 10KHz 40 dB - 20KHz 37 dB
THD: 0.08 % 1KHz at 1V rms out
Distortion THD+N: -80 dB (.01 %) zero "crossover" distortion, mostly 2nd harmonic
Input Sensitivity: 250mV (-9.8dBu) yields 1V out
Input Impedance: 100 kOhm Noble volume control
Maximum Input Level: 5.5dBu or 1.459 Vrms 1KHz, volume control at maximum
Output Impedance (LINE STAGE): 100 Ohms
Maximum Output Level: 17.2dBu or 5.636 Vrms 1KHz, volume control at maximum
Output Power (100 Ohm Headphones): 1W (10 V RMS) (28 V P-P)
Output Power (600 Ohm Headphones): 1W( 25 V RMS) (70 V P-P)
Power Consumption: 170 Watts (1.4 A 120VAC)
Operating Mains Voltage: Factory set for 100V, 120V or 220-240VAC operation for original destination country's mains voltage.
Operating Mains Voltage: changeable with power transformer re-wiring and fuse value change.
Mains Voltage Frequency: 50~ 60Hz
Dimensions: W=19" x L=13"
Top Deck Height: 4"
Transformer Height: 3 1/2"
Suggested shelf height minimum: 10" (depending on height of 300B tube)
Shipping Weight: 28 Ibs.