Finished HiFi Preamplifier Board DIY Audio Amplifier Board Replacement for Marantz HDAM Classic Preamplifier

Finished HiFi Preamplifier Board DIY Audio Amplifier Board Replacement for Marantz HDAM Classic Preamplifier

Description:
- The audio linear amplification circuit for Marantz HDAM has excellent sound quality, excellent low frequencies, full mid-range, delicate high frequencies, comfortable listening experience, and the smell of electronic tubes, which is not comparable to the previous stage of the operational amplifier. Unfortunately, the core tube K170 was discontinued in the later stage, and using K246 and K30 cannot restore its beautiful sound quality.

- This year, we purchased original replacement transistors for Toshiba with identical characteristics to K170. The SMT contains two 2SK transistors with the same characteristics, saving the trouble of pairing. The distortion index is lower. The output adopts high current BD139 and BD140 as Class A outputs, which have better driving force and can even drive low impedance headphones. Pairing with an amplifier is more convenient.

- The material used in this front-end kit is also quite good, with double-sided gold-plated PCB and LM317 337. NOVER gold capacitor voltage stabilization for ON, for WIMA, and for Beijing 718 copper pin resistor, small tube made of BC556 546 with excellent vocals for Philips.

Specification:
- PCB size: 136 x 122mm
- Power supply range: AC14X2 to AC18X2
- Recommended external potentiometer resistance value: 50 - 100K
- Frequency band: 10Hz - 40KHz
- Output impedance: 47K
- Output impedance: 10ohms
- Amplification: 4X (by default), you can modify the resistor to set it from 1X to 20X

Package Included:
- 1 x Preamplifier Board