Rane BB 22 BB 22 Balance Buddy Data Sheet / Manual - Page 2

BB 22 BALANCE BUDDY Application Information Conversion Ratio 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 (this comes from the old power reference of 0 dBm, which equaled 1mW into 600 Ω, which equaled .775 volts). Block Diagram INPUT 1 -10 dBV +4 dBu OUTPUT 1 Driving Impedances Some people wrongly feel you cannot use a transformer to convert between -10 dBV and +4 dBu because of low impedances. This is not a problem as long as you use them to interconnect equipment with at least 15k ohms input impedance. Since most professional products have input impedances of 20 kΩ or greater (50k and 100 kΩ are not uncommon), this should never be difficult. A 15 kΩ load winds up looking like 1 kΩ to the equipment with the -10 dBV output (due to transformer action). This may seem excessively low, but is not in practice. The maximum transformer output level of +24 dBu occurs with an input level of +10 dBV, which equals 3.16 volts. And 3.16 volts driving 1 kΩ only requires 3.16 milliamps, which is a very modest requirement for any -10 dBV equipment to deliver. INPUT 2 -10 dBV Dimensions +4 dBu OUTPUT 2 1.636" Wiring The BB 22 follows AES/ANSI/IEC standards of pin 2 positive and pin 3 negative. Note the shields (commons) of the RCA jacks are not tied together. This provides better ground isolation 0.35" 5.1" of the unbalanced units. A positive signal applied to the tip of 0.15" 0.775" the RCA jack causes a positive signal to appear on pin 2 of the XLR, and vice-versa if signal direction is reversed. 1 OUTPUT 1 INPUT 1 2 OUTPUT 2 INPUT 2 Signal Direction Signal can be converted through the channels either direction. The only problem arises in the gender of the XLR connector. The solution requires same-sex XLR adaptors or special cables. +4dBu -10dBV +4dBu RANE CORP. -10dBV MADE IN U.S.A. ACN 001 345 482 BB 22 BALANCE BUDDY 2.5" 4.225" ©Rane Corporation 10802 47th Ave. W., Mukilteo WA 98275-5000 USA TEL 425-355-6000 FAX 425-347-7757 WEB rane.com Data Sheet-2 All features & specifications subject to change without notice 1-2014