EA10 HI-END Class A Preamplifier Board Headphone Amplifier Board Finished Preamp for Audiophiles

EA10 HI-END Class A Preamplifier Board Headphone Amplifier Board Finished Preamp for Audiophiles

Description:
The preamplifier board refers to the circuit of NORWAY'S famous brand (for ELECTROCOMPANIET). Its voice is thick and powerful, round, smooth, sweet. High-frequency sound is beautiful, and the timbre is warm.

With low frequency, midrange and high frequency equalization, and low frequency dive depth can be used to upgrade our JC-2 and C200V preamps. It can significantly improve systems that sound cold and hard.

It can works as a preamplifier board as well as a headphone amplifier board. Due to its outstanding performance, it can be used to drive your headphones for Sennheiser, Beyerdynamic, AKG, GRADO. It also fits dynamic and low resistance headphones.

Circuit Structure:
FET makes a differential input snubber circuit → differential amplification circuit→ and then sends it to the second stage snubber circuit→ the main voltage amplification circuit→ and finally to the FET push-pull output stage.

The power supply part adopts a regulator circuit. The differential input adopts the original 2SK170 BL grade FET for Toshiba, the voltage stage adopts constant current tube, original second-hand FET (for Hitachi) for output and original rectifier MR754 for ON.

More Details:
- The feedback capacitor is upgraded to more acoustic capacitors for RIFA and SPRAGUE
- The output capacitors are connected in parallel with two 4.7UF capacitors for WIMA. Users can upgrade with a 10UF capacitor
- The temperature-compensated capacitors are upgraded to large S MKP capacitors for Solen
- Imported hifi resistors for KOA, VISHAY, PANASONIC, etc.
- Imported adjustable resistor for BI
- The differential input stage bypass capacitors have been upgraded to the better FG series, which are rarer
- The input adopts the original 2SK170 FET for Toshiba
- The output uses second-hand original FET for Hitachi
- The power supply is a regulator circuit
- The main filter capacitors are upgraded to imported ones BC MKT combination for Philips
- The rectifier diode adopts the original hifi MR754 for ON
- The anti-interference capacitor of the rectifier has been upgraded to WIMA, which makes the details more expressive
- The large heat sink of the PCB has heat dissipation holes to ensure that the heat can be better dissipated, further extending the service life and the overall stability of the board

Specifications:
- Item name: EA10 Class A preamplifier board
- Frequency response: 20-25KHz
- Signal-to-noise ratio: 106dB
- Magnification: 8 times
- Static power consumption: 18+18W
- Amplification form: two sets of single-ended RCA can be used for balanced amplification
- Power supply range: dual AC 32-42V (dual AC 38V recommended)
- Power supply mode: It is recommended to use a 50W transformer for each channel to supply power separately
- Speaker protection: without protection circuit. Additional protection circuit board is required when it works as a headphone amp board
- Total harmonic distortion: ≤0.01%
- Finished board: 240 x 220 x 42mm/9.4 x 8.7 x 1.7" (LxWxH) (including 10mm/0.4", the height of copper pillars)

Package Included:
- 1 x Preamp board
- 1 x Set of copper pillars
- 1 x Set of screws
- 1 x User manual

Note:
- Due to the unstable supply of some components, after some resistors and capacitors are used up, we will replace the components with the ones of the same grade or higher. The actual shipped product may differ slightly from the one pictured . Before placing an order, you can consult the customer service.
- The output FET used on the board is the second-hand original ones for Hitachi. Currently, 2SK213/J76, 2SK214/J77, 2SK215/J78 and 2SK216/J79 are provided. But our board does not specify which of the above models to use due to the supply chain. Thank you for your understanding!