Spectro Acoustics Model 101B
Preamplifier/Equalizer
The quality of a stereo component system lies in the audiophil's choice of equipment. The major influence affecting that quality is the interaction and influence of each component on other components and the culmination of those influences on the human ear. This is where the choice is made in selecting "quality" and whether to accept a particular sound as "right"
All things considered, the perfect listening environment is still the concert hall and reproduction of music must remain subjective. However, we want control over what we hear and have the facility to change what it is that reaches our ears. In musical reproduction this function is relegated to the concepts of tonal compensation, balance and volume. The equipment corollary is the modern preamplifier; a device which offers control over the amount of sound reaching our ears and which particular source we will listen to, (whether it be a tape recording, a phonograph record or a radio broadcast). In most cases, there is the ability to change the tonal content at specifically designated frequencies.
Spectro Acoustics, in attempting to obtain maximum performance value, offers the Model 101B preamplifier/equalizer for audiophiles who want the most in flexibility and performance at a reasonable price.
The Spectro Acoustic Model 101B in order to optimize reliability and serviceability, is designed and constructed to utilize plug-together glass-epoxy circuit boards and 100% monolithic IC circuitry for consistent performance. All controls and connections are human engineered to give simple straight forward operation. The graphic panel of the 101B is a display of exactly what's going on inside of the unit. Control is at the user's finger tips to seek the level and range of sound that achieves personal satisfaction.
The equalizer circuit for the Model 101B is a totally new type based on Spectro Acoustics gyrator synthesis techniques similar to those used in the Model 210 Graphic Equalizer. The design is a hybrid coil/gyrator type which totally eliminates distortion and hum for equalizer circuitry. The filter parameters are optimized for maximum flexibility from a five band design and as an added benefit the highest and lowest frequency bands are "shelving" type to control the response well beyond are "shelving" type to control the response well beyond the extremes of audibility. The usefulness of the equalizer circuitry is further enhanced through its complete availability to line or tape outputs, or total bypass for equalization in/out comparisons.
In phono stage, the Model 101B utilizes an isolated feedback servo op-amp phono stage with ultra-accurate adherence to the RIAA curve. This circuit provides for accurate cartridge response, increased definition of high frequencies and greater dynamic range. Internally accessible cartridge loading components can be adjusted by any qualified and authorized technician to perfectly match the cartridge load for any cartridge.
Specifications
Total Harmonic Distortion: less than .05% at 2 volts rms output, 20Hz to 10kHz, 10 k Ω load
Intermodulation Distortion; less than .01% at any output level below clipping, 7kHz and 60 Hz mixed 1 to 4 (SMPTE)
Noise
Phono Stage: less than 2 mV equivalent input noise, 20Hz to 20kHz, inputs open or shorted (S/N ratio = at least 74 dB below 10 mV reference) Better than 88 dB below full output (ASA standard "A" weighting)
High Level & EQ Stages: less than 30 mV equivalent input noise, 20Hz to 20kHz, inputs open or shorted (S/N ratio = at least 90 dB below 1 V reference) Better than 100 dB below full output (ASA standard "A" weighting)
Frequency Response:
Phono Stage : within 0,5 dB of true RIAA equalization, 20Hz to 20kHz, typically within 0,1 dB
High Level Inputs : within 0,1 dB of absolutely flat response, 20Hz to 20kHz, within 3 dB of absolutely flat response, 5Hz to 100kHz
Gain
Phono Stage : 40 dB at 1 kHz, phono stage alone, 50 dB at 1 kHz, phono +line amplifier (main outputs)
High Level Stage : 10 dB with Level controls set to maximum
Equalizer Stage : Plus or minus 15 dB nominal range of adjustment, within 0,1 dB of unity gain, controls set flat
Dynamic Range
Phono Stage : Overload point is 100 mV at 1 kHz input
High Level Stage : Overload point is 10 V at 1 khz into 10 k Ω load
Port Impedances
Phono Units : 47 k Ω shunted by 220 pF (internally adjustable)
High Level Inputs : 50 k Ω shunted by 10 pF
Tape Inputs less than 600 Ω , resistive, direct coupled
Main Output : less than 600 Ω , resistive, direct coupled
Output Capabilities
Rated Output: 2 volts rms into 10 k Ω load, resistive
Output at Clipping : Greater than 9 volts rms into 10 k Ω load, greater than 5 volts rms into 600 Ω load at 1 kHz
Protection: Fully protected against short circuits at any output level
Power Requirements: 110 to 125 VAC, 50/60 Hz, 14 watts (Standard unit); 220 to 250 VAC, 50/60 Hz, 14 watts (Export unit)
Physical Data
Dimensions (W x H x D): 381 x 152,4 x 140 mm (15" x 6" x 5-1/2")
Optional Wood Cabinet (W x H x D): 412,8 x 184,2 x 421,3 mm
Weight : 10 pounds shipping
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