JBL SG520
¥ 268,000 (around 1970)
Commentary
A control amplifier consisting only of a straight-line type control and a push-button switch without using any rotary knob.
The model number has not changed from the early model to the later model, but the internal circuit has been improved.
It has a built-in 1 kHz test tone oscillator, and when combined with relay control F22, stereo volume balance control called Aural Null Balancing System can be performed.
Although the front panel is an aluminum panel, there are SG520G with a gold panel that matches the finish of power amplifier SE400S, and SE520E with an expert model that can switch the power voltage.
Model Rating
| Type | Stereo control amplifier |
| Output | 3V |
| Frequency band | 20 Hz to 20000 Hz |
| Input sensitivity | Phono:6mV AUX:300mV |
| Total harmonic distortion factor | 0.15 |
| Tone control | High frequency : 20 kHz, + 21 -17dB Low : 20 Hz, ± 17 dB |
| Accessory circuit | Loudness control With Oral Balancer |