Refer to AccuphaseC3850 preamp circuit DIY assembly kit Fully balanced input power amplifier board Class A preamplifier
The product has the functions of balanced input-balanced output, balanced input-single-ended output, single-ended input-balanced output. Also has 2 RCA input options. Truly balanced amplifier circuit, the left and right channel power supply is completely independent, and the separation is very good
The circuit is referenced from the Golden Throat 3850 preamp. The circuit is a preamp worth making and appreciating. If you do it carefully, the effect is much better than the general preamp. It is looser, more delicate, warmer and charming, because it is a classic, far from being a Ordinary electronic tubes and op amp preamps can be compared, and the sound can be compared to the sound of American electronic tubes
The circuit structure is the op amp as the basic amplifier, adding discrete parts to improve the open-loop gain, and using the voltage and current dual feedback circuit to reduce distortion, the output tube uses the British original famous tube ZTX450 ZTX550, class A state output, the music tastes very good, very gallbladder
The NE5534 op amp is used by default, and customers can upgrade it by themselves. The board does not need to be debugged, it can be installed and welded correctly
PCB size: 365X283MM
Transformer input voltage "AC14VX2 to AC18VX2 can be used, and a 24V transformer can be used.
After installing the transformer, the board is 220V input, be careful not to touch the high voltage
The resistance and capacitance of the components are all very high-matched materials to ensure that the circuit can perform 100% perfectly.
Kit material is very good. In addition to various original pairs of tubes. The capacitor adopts the British NOVER main filter, the ELNA Swiss RIFA decoupling, and the Philips military standard resistor. Double-sided military PCB, etc.