EA40 500Wx2 Class A Power Amplifier Board for ON Semiconductor to Upgrade E405/550/KSA50 for Accuphase

EA40 500Wx2 Class A Power Amplifier Board for ON Semiconductor to Upgrade E405/550/KSA50 for Accuphase

Version for ON Semiconductor:
Transistor for ON Semiconductor has better musical analysis and timbre, and is suitable for customers who are not too demanding on thrust and dynamics, but pursue sound texture and timbre.

It is recommended that the weight of the unilateral heat sink should be more than 3.5KG.

Description:
EA40 is a power amplifier board. Three-frequency balance, natural and audible sound, full and clear sound, wide sound field, strong and powerful low frequency and good low frequency expression; overall control and thrust are strong. Applicable to some speaker units which are hard to push, such as for Dynaudio and HIVI.

The speaker protection circuit on the board has a mirror-symmetrical design for two channels, which makes the wiring in the box more convenient and beautiful during installation. The final EA40 pure power stage, when doing the actual listening test, is very good in tone, thrust or control at low frequencies, and the overall performance is relatively good.

Features:
- The circuit is designed for high-bias current class A and B working state to obtain very high output performance, and can also be adjusted to pure class A state
- Compared with the large loop feedback structure, the local loop feedback can obtain greater thrust and better control force
- The FETs used on the board are matched in a precise fashion, and the matching error of the same polarity is within 3%
- Manual + computer analysis of layout and wiring technology used, so that the board can get a higher signal-to-noise ratio
- The current mirror input structure makes the board get a more stable output under large dynamics
- Perfect speaker protection circuit structure to ensure the safety of speakers during normal use
- Resistors, capacitors, diodes, and voltage regulators are imported components to ensure higher stability of the board
- The left and right channels are completely independent, with mirror symmetrical design
- Audiophile resistors are imported, such as for KOA, VISHAY, and Panasonic
- Use imported or equivalent capacitors
- Imported 30A sealed relay not easy to oxidize and more stable
- The first-stage decoupling capacitors are imported, and the second-stage decoupling capacitors are for Siemens
- Input coupling capacitor for ERO MKT
- Feedback capacitor for Philips axial
- Small-capacity capacitors are imported
- A pair of PCB substrates 2mm/0.08" in thickness

Specifications:
- Gain: 28.9dB
- Signal-to-noise ratio: 108dB
- Frequency response: 20Hz-30KHz (± 0.1dB)
- Damping factor: 500
- Input impedance: 33K
- Rated power: 250W/8Ω; 500W/4Ω
- Output power: 500W*2
- Working voltage: main voltage dual DC 50V/6.8A, with speaker protection AC 12V/1A
- PCB board: 298 x 78 x 2mm/11.7 x 3.1 x 0.08"
- Input Sensitivity: 1.26V/RMS
- Total harmonic distortion: ≤0.01%
- Finished Board Dimensions: 298 x 99 x 38mm/11.7 x 3.9 x 1.5"

Package Included:
- 1 x Set of Amplifier Board

Note:
- Schematic diagram is not included.