61 CABLE RETURN
Connect one end of a cable with 1/4" plugs to this jack, the other end to jack 62. Only Mono cables can
be tested with this feature.
Tip:
This test circuit is a very useful tool: You are able to test speaker cables as well as guitar cables and
patch cables (only the mono wire is tested!) for FX device connections. Due to the higher resistance of
longer cables you may find that the 12 Z LED instead of the 8 Z LED indicates that the cable is O.K.
62 TEST JACK
Connect a speaker cabinet(s) to this jack for an impedance check. For the cable test, insert one end of
the cable to this jack.
IMPORTANT:
Before testing a cable, make sure that the other end of this cable is not connected to a
poweramp output; this may damage the test circuit. Even a cabinet that features a Thru jack
may not be connected to a poweramp output. It is OK to connect it to another. Disconnect the
cable or the cabinet after the test to avoid unnecessary strain on the internal power circuit.
PLEASE NOTE:
During the impedance check, you may find that several LEDs illuminate or flicker at the
same time. Possible causes: the connection between the plug and the jack is faulty or a high level of
peripheral noise is generating voltage in the speakers that influences the test circuit. Due to the
measuring method, deviations in values are possible. The speaker's DC resistance provides delivers an
approximation of a the exact value. This circumstance explains why you might encounter a discrepancy
between the displayed and the true value. When you are sure about the impedance of a cabinet (or of
several interconnected cabinets), use this value to set the impedance selector (76) to the correct position.
In practice,the displayed value should not vary more than one LED bar from the true value. Use thick,
short cables for the impedance test to avoid faulty measurements due to higher cable resistance.
63 < 4 Z; CABLE SHORT CIRCUIT
This red LED flashes to indicate the following results during the impedance check: an impedance lower
than 4 ohms, possibly a shortcircuit in the connector cable (test the cable separately!), or a shortcircuit
inside the cabinet. During the cable check, it indicates a shortcircuit between the wires or in one of the
plugs.
64 4 Z
This green LED indicates an (overall) impedance of 4 ohms during the impedance check.
65 6 Z
This yellow LED indicates the following results during the impedance check: a relatively unusual (overall)
impedance of 6 ohm. Possible cause: A speaker's tolerance (it may be an 8 ohm system), faulty cables, or
poor connections between plugs and jacks (in this case, it may be a 4 ohm system), or a parallel circuit
consisting of three 16 ohm speakers.
66 8 Z; CABLE O.K.
This yellow LED indicates the following results during the impedance check: an (overall) impedance of 8
ohms. During the cable check, it indicates cable is intact.
67 12 Z
This yellow LED indicates the following results during the impedance check: a relatively unusual (overall)
impedance of 12 ohms. Possible cause: A speaker's tolerance (it may be a 16 ohm system), faulty cables
or poor connections between plugs and jacks (in this case it may be an 8 ohm system), or a serial circuit
consisting of a 4 ohm and an 8 ohm speaker.
64 4 Z
This green LED indicates an (overall) impedance of 16 ohms during the impedance check.
69 > 16 Z; CABLE BREAK
This red LED flashes to indicate the following results during the impedance check: an impedance greater
than 16 ohms, possibly a break in the connector cable (test the cable separately!), or a break the
cabinet's internal wiring. During the cable check, it indicates a break in the wires or in one of the plugs.
inside the cabinet. During the cable check a break in the wires or in one of the plugs.
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