Tips: Due to the different assembly batches of the components on the board, the brands, models, and specifications of some capacitors will be slightly different. The components and parameters assembled on the received board shall prevail!
The NE5532 integrated block on the circuit board is genuine for second-hand teardown.
Power supply: ±5V ~ ±15V
Balanced XLR to single-ended RCA output Dual op amp line finished board Small size: The line is designed by the famous British power amplifier designer Douglas Self. The unique circuit design makes the line machine have excellent performance with ultra-low distortion and low noise.
Circuit principle:
The distortion and noise of this line is much lower than that of a normal circuit, so the circuit looks less complicated and slightly more complicated, and the purpose is low distortion and low noise. In general, to convert the balanced signal into an unbalanced (single-ended) output signal, you can use 1/2 NE5532 plus 4 10K resistors, which can be achieved by connecting IC2A in the figure. At this time, R5~R8 are taken as 10K, a pair of balanced signals are input from the left end of R5 and R6 respectively, and a single-ended output signal can be obtained from the right end of R9. This differential amplifier circuit is quite simple. The output noise is also low, which can reach -104dBu (0dBu=775mV), but still feels a lot of noise. For this reason, the so-called double balance stage is adopted, that is, two differential amplifier stages are composed of IC2A and IC2B, and the balance is received at the same time. The input signals are added together to partially cancel out the uncorrelated noise, resulting in a 3dB noise reduction and improved circuit common-mode rejection ratio (CMRR).
Further improvements are also added to the first stage voltage followers IC1A, IC1B before IC2A and IC2B. This not only improves the input impedance, but also reduces the resistance of the eight resistors R5, R6, R7, R8, R13, R14, R15, and R16 of IC2A and IC2B from the original 10K to 820 ohms, greatly reducing the thermal noise of the resistor. Finally, the noise of this stage is reduced by -112dBu, which is 8dB better than the traditional single-difference circuit above.
One board is mono,
Exquisite FR4 double-sided fiberglass board, gold-plated high-quality PCB board (65 × 27mm), circular arc grounding. Imported high-quality RC components. Japan KOA 1/4W high-precision five-color ring metal film resistor, Nissan brand electrolysis, gold-plated IC socket (convenient upgrade), US-made NE5532 dual op amp 2, connected to ±5V ~ ±15V stable voltage to work.
Working mode: This circuit board is used for CD player balance XLR signal output is converted to single-ended RCA output to the next level (preamp or power amplifier) via this line.
This board can be replaced with a better op amp, such as AD826, AD827, OPA2134, OPA2604, OPA2111 and other high-end op amps, the effect of the vertical.
Friendly reminder: When using, pay special attention to the supply voltage should not exceed ±18V, and the three lines that balance the XLR signal cannot be connected incorrectly. The components on the board are different due to different assembly batches. The brands, models and specifications used for some capacitors will be slightly different. The components and parameters on the board will be subject to the acceptance!
PACKAGE
1PCS