A60+ 400W Hifi Power Amplifier Board Two Channel Power Amp Board Kit (2SC945) Refers to Circuit for Accuphase

A60+ 400W Hifi Power Amplifier Board Two Channel Power Amp Board Kit (2SC945) Refers to Circuit for Accuphase

Descriptions:
The A60+ board is improved based on the A60, and the 2-channel A60+ can support 16 pairs of transistors, which has better driving force and it can be adjusted to a class A power amplifier board. Its rectifier section is enhanced to a 120A low-internal resistance high-speed tube for better dynamics.

Features:
- Input circuit adopts C945 and A733 HIFI transistors featuring low noise, good vocals and delicate midrange sounds
- Schottky 30CPQ150 60A low internal resistance rectification
- DC servo circuit without zero adjustment
- Original MRS25 1% metal film resistor for Philips, high stability metal film resistor, with low current noise, low temperature coefficient and low tolerance

Transistor Matching and Effects:
Different transistors have different timbres. Please note that this is a power amplifier board. When paired with 2SC5200 and A1943, there will be delicate, full, but slightly darker sound. When paired with transistors for ON, the timbre is bright, the layered overtones are very good, and the rhythm is strong. When paired with transistors for Sanken, it has good strength, and low frequency is strong and powerful.

Board Test:
- The circuit already has a rectifier circuit, so it only needs to connect a transformer, no need to attach an external rectifier board. It is very convenient to wire. The fully symmetric architecture combined with the precision pair of transistors makes the midpoint very stable without debugging.
- Adjust the quiescent current of transistors to 50-100mA per transistor. The board has 1 test point, and the voltage drop at test point 2 is 20-30MV.
- Note: Remember to add mica sheets when installing transistors, and mica sheets must be coated with thermally conductive silicone.

Specifications:
- Operating voltage: AC24Vx2 ~ AC42Vx2 and AC12V (AC12V for protection circuit)
- Output power: 200W 8Ω; 400W 4Ω
- Distortion: 0.002%
- Signal-to-noise ratio: >100dB
- Frequency response: 5HZ-40KHZ
- PCB size: 273 x 88mm/10.7 x 3.5"
- Mounting diameter of large capacitor: 25-30mm/1-1.2"

Component Configuration Recommendation:
Resistors for Philips (by default) are used, component for Omron is used to to protect the circuit, and input transistors are Japanese HIFI transistor 2SC2240 and 2SA970. The driving part uses transistors NJE15034/35 for ON. The board can also use 6 pairs of 2SC5200 and A1943, or 4 pairs of transistors for Sanken. And transistors for ON can also be used.

Package Included:
- 2 x Power Amp Boards

Note:
- It is a two-channel power amplifier and there are two boards in the package.
- 16 pairs of transistors and 8pcs 10000UF main capacitors are not included in the package.
- Assembling is needed.