Free shipping 1pcs Full - LS69 Balance Tube Pre Amplifier PCB Empty Board 6922x4 | Электроника

Free shipping 1pcs Full - LS69 Balance Tube Pre Amplifier PCB Empty Board 6922x4 | Электроника

1pcs Full - LS69 Balance Tube Pre - Amplifier PCB Empty Board 6922x4

Why use XLR balanced transmission?

Audio signal interface has a balanced, unbalanced connection of the points, the so-called balance, imbalance is relative to the "potential" is concerned, if a signal at both ends of a moment is greater than the "ground" a certain value, the other end Is less than "ground" a certain value of potential, which we call balance; if a signal at both ends of a moment there is always one end equal to "ground" potential, this situation we called imbalance.
The advantages of balanced transmission is the frequency-frequency characteristics, anti-interference ability, so often used professional equipment. Unbalanced transmission, because the ground line is used to transmit audio signals, but also shielding effect, so unbalanced connection of the anti-electromagnetic interference is poor, easy to introduce periodic power supply interference and other noise.
The formation of balance and imbalance Two transmission methods are determined by the circuit of the device. We know that the amplifier circuit, whether the tube circuit, transistor circuit or integrated operational amplifier are unbalanced, in other words, these circuits are a total of "ground", that is, input and output are single-ended, and "ground "Is their common, input and" ground "to form the input loop, the output and the same" ground "to form the output circuit. Therefore, the circuit input and output directly leads to the chassis is the most simple and most economical solution, which is the home appliance class, most consumer electronics products will use the key to unbalanced transmission.
There is a saying that the transmission distance of civil audio equipment is short, the use of XLR balanced transmission is not only high cost, but there is no great significance, but in fact high-end audio equipment often equipped with XLR balanced interface, the actual sense, XLR Balanced connection RCA than the unbalanced connection background is quieter, the sound is more energy sense, this is because in addition to balanced transmission mechanism can effectively suppress common mode noise, before and after the level of good impedance matching can make the amplification device to produce the largest Of the energy, such as the use of unbalanced connection, the output signal amplitude will be reduced by half, the signal level will be reduced by 6dB, audio signal transient response and distortion and other indicators also declined.

Using four 6922 tubes.(default not included tubes)


PCB size:230 x 150  (mm)


the price is for  one bare PCB

Package included: LS69 f preamp PCB    x 1