BGW Model 203
¥ 280,000 (around 1978)
Commentary
A control amplifier built with new technology and without compromise for "outstanding performance".
The RIAA playback curve is divided into two parts : 1 kHz or less belongs to the first stage, 1 kHz or more belongs to the second stage, and the feedback curve for each stage is designed to reproduce the best part of the RIAA curve.
This increases the accuracy of the phono stage and provides twice the performance compared to other amplifiers.
The phono stage divides the equalizer into two stages, with individual differential circuits for turnover and roll-off, and inverted Darlington circuits for voltage amplification.
The power supply is stabilized by introducing a Darlington emitter-follower connection ± voltage control stabilized power supply circuit. In addition, the emitter-follower circuit is used in each section for low output impedance.
In addition, the power transformer is housed in a copper shield case, and the AC line is isolated from all circuits to achieve a high S / N ratio.
A 13-position rotary switch is used for tone control, allowing independent control of 3 dB steps on the left and right sides. The Baxandall type filter has a differential-amplified and voltage-amplified circuit configuration.
The master volume is a 22-position thick film detent volume.
In addition, High gain and Low gain can be selected by switching the switch.
High-quality parts such as GE, Sprag, RCA and Verden are used for each circuit part.
Equipped with pre-switch button and power switch button.
The pre-switch button controls the power supply of the preamplifier and the rear panel PRE and PWR outlets, and the power switch button controls the PWR outlet when the pre-switch button is ON.
Equipped with High and Low filters, which act as a scratch filter and a subsonic filter, respectively.
There was a wood case sold separately.
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Model Rating
| Type | Control amplifier |
| Input impedance | Phono1/2 : 47k Ω Tuner, Aux1/2, Tape1/2 : 90k Ω |
| Gain | Phono amplifier : 42 dB High-level amplifier : 22 dB (high position) 10 dB (Low position) |
| RIAA deviation | 20 Hz to 20 kHz ± 0.25 dB |
| Frequency characteristic | Phono amplifier : 20 Hz to 20 kHz ± 0.25 dB High-level amplifier : 20 Hz to 20 kHz ± 0.2 dB |
| Signal-to-noise ratio | Phono:88dB High Level : 80 dB (High position) 90 dB (Low position) |
| Maximum allowable input | Phono:100mV(1kHz) High Level Amplifier : 10 v |
| Output voltage / load impedance | Line out : 8Vrms/600 Ω (+ 20 dBm) Tape out : 10Vrms/5k Ω Rated output : 4V/rms/5k Ω |
| Total harmonic distortion factor | 0.01% or Less (20 Hz to 20 kHz, Rated Output) |
| Tone control | Bass : ± 18 dB (50 Hz) Treble : ± 18 dB (15 kHz) |
| Filter | Low : 20 Hz, 18dB/oct. High : 12 kHz, 18dB/oct. |
| Power supply voltage | 120 VAC (90 V ~ 130 V), 240 VAC (220 V ~ 240 V), 50Hz/60Hz |
| Power consumption | 10W |
| External dimensions | Width 483x Height 133x Depth 273 mm |
| Weight | 8.1kg |
| Sold Separately | Wood case |