Rane BB 44X BB 44X Balance Buddy Manual / Schematic

BB 44X / OPTION 88

OPERATORS MANUAL

Application Information

Driving Impedances

Some people wrongly feel you cannot use a transformer to con-

vert between -10 dBV and +4 dBu because of low impedances.

°is is not a problem as long as you use them to interconnect

equipment with

at least 15 kΩ 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 diﬃ-

cult. A 15 kΩ load winds up looking like 1 kΩ to the equipment

with the -10 dBV output (due to transformer action). °is may

seem excessively low, but is not in practice. °e maximum trans-

former 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

°e BB 44X follows AES/ANSI/IEC standards of pin 2 positive

and pin 3 negative. Note the shields (commons) of the RCA

jacks are tied for the Inputs and the Outputs but not to each oth-

er. °is allows ground isolation of stereo Input and Output pairs.

A positive signal applied to pin 2 of the 3-pin connectors causes

a positive signal to appear on the tip of the associated RCA jacks,

and vice-versa.

Signal Direction

Signal can be converted through the channels either direction.

°at means there is the possibility of having 4 channels -10 dBV

unbalanced to +4 dBu balanced, or vice versa (in the standard

unit). °e only problem arises in the gender of the XLR con-

nector. °e solution requires same-sex XLR adaptors or special

cables.

Chassis Grounding

A tapped hole and a #6-32 screw is provided for chassis ground-

ing purposes. Good practice dictates earth-grounding the BB

44X. If the grounding integrity of the rack screws is in doubt,

run a wire from this screw to a known earth ground.

Expansion Assembly

°e OPT 88 (Option 88) expands the BB 44X into an eight

channel model. °e OPT 88 consists of a printed circuit board

with four additional transformers and jacks soldered in place.

°e OPT 88 installs easily in the blank side of the BB 44X.

Assembly is simple: remove the cover, install the board in place,

and secure with the supplied mounting screws. No soldering

required; all you need are #1 and #2 Phillips screwdrivers. See

the illustration on the next page.

°e OPT 88 may be used in some environments without the

BB 44X, however best RFI rejection is obtained using the cold

rolled steel metal chassis of the BB 44X.

INPUT 1

T4

OUTPUT 1

9

11

4

2

3

2

1

+4 dBu

-10 dBV

11

4

2

INPUT 2

+4 dBu

9

2

T3

-10 dBV

OUTPUT 2

3

11

4

2

1

OUTPUT 3

+4 dBu

9

2

T2

-10 dBV

INPUT 3

3

11

4

2

1

OUTPUT 4

+4 dBu

9

2

T1

-10 dBV

INPUT 4

3

1

Rane BB 44X BB 44X Balance Buddy Manual / Schematic

Rane BB 44X Manual

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