Hi Chris
When you say for TRS cable RING and SLEEVE need to be bridged. What exactly does that mean?
Could I use two separate TRS cables ( one from ‘R’ and then other from ‘L+R/L’ of PSR 970) and connect them to two separate inputs on a mixer?
I’m trying to use balanced instrument cables for both outputs on PSR 970. Would using two TRS cables work and is it better to do so? Thanks.
Hi Sandeep,
A "
TS" plug has only
two contacts (
Tip and
Sleeve) and is used for
unbalanced Mono connections.
TIP = Signal
SLEEVE = Ground/Shield
A "
TRS" plug has
three contacts (
Tip,
Ring and
Sleeve) and is used for
balanced Mono connections (or
unbalanced Stereo connections, e.g. for headphones).
TIP = Signal (+ phase, "hot")
RING = Signal (- phase, "cold")
SLEEVE = Ground/Shield
Electrically bridging RING and SLEEVE contacts of a TRS plug (e.g. by soldering a short wire into the connector), converts a balanced cable/signal to an unbalanced cable/signal. (TIP is still "Signal +" then, but SLEEVE is "Signal -"
and "Ground/Shield".) This is absolutely necessary to feed an unbalanced output signal into a balanced input when not using a standard "TS to TS" cable or a DI box.
As I wrote, all Yamaha arranger keyboards have
unbalanced Line Outputs, and you have to use
unbalanced audio cables with a
TS plug on the keyboard end.
Inside the Line Output sockets, the "RING" contact is NOT CONNECTED. So if you would use balanced cables ("TRS to TRS" or "TRS to XLR male") to connect the keyboard to balanced Mixer Inputs, the Mixer will only receive the plus (+) phase of the Signal but not the minus (-) phase.
This results in a
6 dB weaker input signal on a balanced Mixer input (compared to a balanced signal), and
hum can also occur because the RING contact of the TRS plug is not connected on the keyboard side. So the Mixer Input for the minus (-) phase of the signal is OPEN. The best way to avoid this problem is simply to use a "TS to TS" cable. "TRS to TRS" or "TRS to XLR" cables
can be used if either RING and SLEEVE contacts are bridged inside the TRS plug or alternatively Pin 1 and Pin 3 are bridged inside the XLR plug.
If the keyboard is to be connected to balanced inputs of an external mixer or active speakers, a stereo DI box (or two separate mono DI boxes) must be used. The DI box is connected to the line outputs of the keyboard with the shortest possible "TS to TS" cables and converts unbalanced TS input signals into balanced XLR signals with low impedance, which can also be transmitted without interference over longer distances.
For relatively short distances (less than 3 - 5 m) unbalanced audio cables are normally sufficient. However, they should not be routed parallel to power cords or very close to power adapters.
By the way, I use the following DI boxes:
- PALMER PAN 04 (stereo, passive)
- PALMER PAN 04A (stereo, active, phantom power or external power adapter needed)
Hope this helps!
Best regards,
Chris