TOA Electronics U-13R - Unbalanced Line Input Module with High/Low Cut Filters and Mute-Receive for 900 Series (Dual RCA) - Manual (Page 15)

IMPEDANCE MATCHING
Most modern audio devices have LOW Impedance outputs
which are designed to drive HIGH Impedance inputs. This
results in
Maximum Voltage Transfer - almost all of the
output's signal voltage is transferred to the input. This is also
referred to as a
Bridged connection.
Impedance matching (output impedance to input impedance)
results in
Maximum Power Transfer and causes
approximately 6 dB of signal voltage loss. This often exceeds
the source device's "minimum load impedance" specification
causing distortion or, at worst, damage to the source's output
circuitry.
L-01
L-01 Series Line Matching Input
• For Applications Requiring 600 Ohm Line Matching.
• Transformer Isolation (600
Ω
) minimizes ground loop
problems when connecting remote equipment (greater than
15 feet).
• Connector: removable terminal block (L-01S).
Input Impedance 600 ohms, balanced transformer-isolated
Sensitivity -16 dBu
Gain -2 dB
CONNECTOR DIAGRAMS
SPECIFICATIONS
BLOCK DIAGRAM
LINE INPUT MODULES: LINE MATCHING PAGE 16
L-01F
L-01F (Balanced/Unbalanced*)
L-01S (Balanced/Unbalanced*) (old style)
L-01S (old style) L-01S (new style)
Maximum Voltage Transfer occurs when input impedance
equals at least ten times the source device’s output
impedance.
For example, if the source's output impedance equals 600
Ω
,
the input impedance of the next device should equal at least
6 k
Ω
or greater.
Tip! You can convert the input impedance of an “L” module to
10 k
Ω
by locating and cutting "R1" (680
Ω
) on the module
PCB. This will result in approximately 6 dB of additional gain,
assuming the source’s output impedance is 600
Ω
.
* For unbalanced sources, use a shielded, twisted pair and connect the
output to Hot and Common (inner conductors). Connect the shield to
Earth at the module and leave unterminated (floating) at the source.
L-01S (Balanced/Unbalanced*) (new style)