Rane BB 22 Datasheet - page 2
Data Sheet-2
BB 22
BALANCE BUDDY
All features & specifications subject to change without notice DOC 102929
©Rane Corporation 10802 47th Ave. W., Mukilteo WA 98275-5098 USA TEL 425-355-6000 FAX 425-347-7757 WEB www.rane.com
Block Diagram
Dimensions
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).
Driving Impedances
Some people wrongly feel you cannot use a transformer to con-
vert 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 dif-
ficult. A 15 kΩ load winds up looking like 1 kΩ to the equip-
ment 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.
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
of the unbalanced units. A positive signal applied to the tip of
the RCA jack causes a positive signal to appear on pin 2 of the
XLR, and vice-versa if signal direction is reversed.
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.
INPUT 1
-10 dBV
+4 dBu
-10 dBV
+4 dBu
INPUT 2
OUTPUT 1
OUTPUT 2
4.225
"
0.15"
2.5"
5.1"
0.775"
0.35"
1.636"
OUTPUT 1
OUTPUT 2
+4dBu
+4dBu
-10dBV
-10dBV
INPUT 2
INPUT 1
BALANCE
BUDDY
RANE CORP.
MADE IN U.S.A.
ACN 001 345 482
1
2
BB 22