quote:

---

Balanced and Unbalanced Reference Voltage:

For consumer audio products using unbalanced RCA connectors, the reference signal level is -10dBV. This is equal to reference voltage level of 0.316 Vrms. 0 dBV is a voltage reference point equal to 1.0 Vrms. Remember that the dB level is a LOG ratio of two voltages.

=20*LOG(0.316/1) #732; -10 dB

For pro audio products using balanced XLR connectors, the reference signal level is +4dBu. This is equal to voltage reference level of 1.23 Vrms. 0 dBu is a voltage reference point equal to 0.775 Vrms.

=20*LOG(1.23/0.775) #732; +4 dB

When a home audio equipment with an RCA output is connected to a pro audio equipment#8217;s XLR input, the signal will have to increase by as much as 12 dB. The casual observer would think to convert -10 dBV to +4 dBu, you would need 14 dB of gain. The casual observer would be wrong. You only need 12 dB of gain. The reason is not only do you change levels, you also change reference levels -- from dBV to dBu. The first (dBV) references everything to 1.0 volt, while the second (dBu) references everything to 0.775 volts.

=20*LOG(1.23/0.316) #732; 12 dB

As soon as you make an unbalanced connection at one end of a wire, the whole thing becomes unbalanced. So for maximum noise immunity, you should use balancing adapters.

---