Introduction:
HV2-SE is designed based on the original HA5000 headphone amplifier circuit. ZERO-ZONE has the original HA5000 re-engraved circuit, so it can design the HV2-SE circuit instead of some copy products from other vendors. Due to the large overall size of the original version of HA5000, many jumpers, step-by-step debugging is required, and 0.125W small resistors and input-level transistors are increasingly rare in the market, and even close resistance values are very difficult to find.
SO, ZERO-ZONE castrated the original circuit directly, leaving only the core circuit to design the HV2-SE work, so that more players can make it. If you still have a strong feeling for HA5000, you can go to my store to buy the original re-engraved version of HA5000 PCB.
HV2-SE Technical highlights:
1. Miniaturization: The original super large PCB is reduced to the current small size of 100mm*100mm to fit various small chassis.
2. Modify the dual-single independent power supply form. After the modification, only one transformer + rectifier bridge is needed to filter and stabilize the power supply for dual-channel, reducing investment costs.
3. Change the original electronic filtering method to three-terminal voltage stabilization to supply power to the input stage and voltage amplification stage, and the ripple factor is lower.
4. Optimize the first-level constant current source, optimize the adjustable single-tube JFET constant current source to a dual-loop constant current source, and set the current to 1mA per tube, which is consistent with the original machine, reducing debugging steps.
5. Cancel the coupling capacitor input part attached to the original machine, and retain the pure direct couple input. After comparison, the pure direct couple input has more direct sound quality and less noise.
6. Keep the original features, use AB carbon film resistors for signal input and feedback.
7. Change the drive stage to C3421-A1358 with higher current.
Input voltage: AC 15V--0--15V (transformer not less than 30W), R-Core transformer is recommended.
PCB Size: 100mm * 100mm
DIY Kit Debugging method: (Output transistor current 100mA)
1, Measure the two points of TP, adjust the 1K adjustable resistance, so that the voltage of the two points of TP is 47mV.
2. Measure the midpoint voltage and adjust the 100R adjustable resistance to make the midpoint voltage close to OmV.
NOTE 1: The output transistor is an old tube from the original disassembled machine.
NOTE 2: We have DIY kit or finished board (Optional)
◆ DIY kit ---- All parts need you to solder and test it.
◆ Finished board ---- All parts have been welded and tested OK.
