Roland SRA-50 Working Stereo Power Amplifier Mixer BK

Compact Roland SRA-50 power amplifier mixer with 2 MIC and LINE inputs, LINE OUT, and BASS/TREBLE adjustment functions.

Internal cleaning was performed using air blowing, and normal operation has been confirmed.
Input signals were applied to MIC, LINE 1, and 2, and it was confirmed that they output normally from the speakers.
PHONES also output normally (sound from speakers is cut off).
LINE OUT also outputs normally.
BASS and TREBLE adjustments are quite effective.
When the MIC volume is at maximum, there is a slight crackling sound.
There is no crackling on other volume controls.
As this is a used item, there are signs of age-related wear such as scratches and dirt on the exterior case.
No claims or returns accepted.

A feature of this amplifier is that sound is produced the moment it is powered on.
Normally, medium to high output amplifiers have a muting relay in the speaker output, and no sound is produced for several seconds.
Many older amplifiers suffer from degraded muting relay contacts due to age, leading to problems such as no sound or reduced volume.

Without using a muting relay, it is normal for loud noise to come from the speakers when the power is turned on, but this unit electronically mutes the output, so the noise when powering on is only a small pop.
There is no sound when the power is turned off.
This is likely a testament to the skill of Roland's design team.
The absence of a muting relay reflects the professional audio philosophy of delivering signals to the speakers without loss over the long term.

Furthermore, this unit is an AB class analog amplifier with a heavy, large toroidal core transformer. Many people appreciate its sound, and it remains popular today.
Subsequent models in this series have transitioned to PWM Class D digital amplifiers.

- Model: SRA-50
- Input Terminals: MIC, LINE 1, LINE 2
- Output Terminals: Speaker Terminals, LINE OUT, PHONES
- Adjustment Functions: BASS, TREBLE
- Power: AC 100V, max 84W
- Maximum Output: 50W x 2 (4Ω)
- Design: Compact 1U half-rack size chassis
- Overload Indicator: Yes
- Manufacturer: Roland
- Accessories: Instruction Manual (copy)