Assembled Headphone Amplifier Board Compared with the commonly reproduction of Beyerdynamic A1, we improved: using class-A series type of voltage regulator to provide more silent power supply. Integrated earphone protection circuit. total 4 MOSFETs for for power output. Use double op amp design, double op amp per channel, with higher channel separation. all-in-one design, single-point grounding, ground resistance is close to the 0.02 ohm resistance value, low noisedesign. PCB is small and flexible, more suitable for all kinds of chassis installation. More cost-effective sound modification plan. PCB SIZE:127 x 152MM Power requirements: AC?15-0-15?~?18-0-18V?,I ?0.5A; Best:AC 15-0-15; I=1A Product configuration Finished board: Based on the well-tested board on the standard version kit, we verified all key points' voltage, and used the signal generator and oscilloscope for analog waveform double verification. We will not use this board for listening test. All finished pcbs are all carefully hand-soldered and fully tests. Schematic & key point of debugging.

Assembled Headphone Amplifier Board Compared with the commonly reproduction of Beyerdynamic A1, we improved: using class-A series type of voltage regulator to provide more silent power supply. Integrated earphone protection circuit. total 4 MOSFETs for for power output. Use double op amp design, double op amp per channel, with higher channel separation. all-in-one design, single-point grounding, ground resistance is close to the 0.02 ohm resistance value, low noisedesign. PCB is small and flexible, more suitable for all kinds of chassis installation. More cost-effective sound modification plan. PCB SIZE:127 x 152MM Power requirements: AC?15-0-15?~?18-0-18V?,I ?0.5A; Best:AC 15-0-15; I=1A Product configuration Finished board: Based on the well-tested board on the standard version kit, we verified all key points' voltage, and used the signal generator and oscilloscope for analog waveform double verification. We will not use this board for listening test. All finished pcbs are all carefully hand-soldered and fully tests. Schematic & key point of debugging.

Beyerdynamic A1 Headphone Amplifier, tested and working. A few minor scuffs, as pictured, and comes with a replacement power cord. Made in Germany.

beyerdynamic Headphone Amplifier A1 German Has some scratches on the outside. Does not come with original cord, I am providing a cord that powers it on but is not the original. I have powered it on, otherwise untested.

Eingangsimpedanz 50 k?, Maximalverstärkung 18 dB, Frequenzgang 1 Hz – 100 kHz (-1 dB), Klirrfaktor 0,001 % bei 170 mW/ 250 ?, Kanaltrennung > 89 dB, Ausgangsleistung: 100 mW / 600 ?, 170 mW / 250 ?, 150 mW / 30 ?, Fremdspannungsabstand >100 dB Ausgangsimpedanzen Line Out (je nach vorgeschaltetem Gerät) 100 ? Kopfhörerausgang, Leistungsaufnahme < 15 W über internes geregeltes Netzteil, Abmessungen 250 x 225 x 50 mm (Gehäusemaße mit Rahmen) Anschlüsse (Audio) Kopfhörerbuchse mit vergoldeten Kontakten 1 Line Ausgang 2 Audio-Eingänge über vergoldete Cinchbuchsen Netzteil 220 - 240 V/ 50 - 60Hz Gewicht ca. 2,3 kg

beyerdynamic Headphone Amplifier A1 German. Used, good working condition, minor cosmetic wear, please refer to pictures.