Rear Panel Operation
ENGLISH
SERIAL / PARALLEL FX LOOP (12)
The JVM is equipped with a series / parallel FX loop. Connect your external FX equipment input to the JVM SEND jack, and the FX output to the JVM RETURN jack. As described previously, this effects loop can be bypassed from the front panel and the amount of effect can be dialed in with the MIX control.
The
When MIX is set to WET all the signal goes through the external loop, adding more direct (unprocessed) signal as you turn it towards DRY. This allows you to mix any amount of the external effect without loosing or degrading the direct signal quality.
When mixing the WET and DRY signals the external effects processor’s output should be configured to remove the direct (unprocessed) signal or unpleasant phasing effects may occur when mixing it again in the amplifier. If the amplifier sounds thin after connecting an external effect check that no direct signal is being returned from the processor’s output.
Note that if the FX loop is ON and the MIX control is set to WET without an external processor connected, the amplifier will be muted.
POWER AMP INSERT / SERIAL LOOP (13) This is a passive loop connected right before the master controls. It is a line level loop so it is recommended to only use high headroom devices to avoid signal degradation. Plugging only into the return jack allows the use of the JVM’s power section overriding the preamp.
Master controls and the emulated line out are located after the serial loop so it is still possible to take advantage of those features when using an external preamplifier. The loop can be taken off the circuit by pressing the BYPASS switch, but as opposed to the Series / Parallel loop this switch cannot be programmed.
EMULATED LINE OUT (14)
The pre master volume signal, processed through a 4x12 speaker cabinet emulator and electronically balanced is made available at this connector.
FOOTSWITCH (15)
Connect the supplied footswitch using any standard 1/4" jack mono lead. Using any other type of footswitch rather than the supplied will have no effect and will be ignored by the amplifier.
MIDI In / Through (16)
Connect any external MIDI equipment to the MIDI In DIN socket. A copy of the signal in this connector will be available on the MIDI thru socket to allow daisy chaining of MIDI equipment. Note that the JVM only accepts incoming data and it is not able to send any MIDI commands.
SPEAKER Outputs (11)
There are 5 speaker outputs available on the rear panel. They are labelled according to the intended impedances:
16 Ohm: connect any 16 Ohms guitar cabinet to this jack.
8 Ohm: connect a single 8 Ohms guitar cabinet or two 16 Ohms guitar cabinets.
4 Ohm: connect a single 4 Ohms guitar cabinet or two 8 Ohms guitar cabinets.
WARNING: Although the JVM amplifier has 5 speaker outputs, never attempt to connect more speakers than rated. The safe combinations are 1x16 Ohm, 1x8 Ohm, 1x4 Ohm, 2x16 Ohm or 2x8 Ohm. Any other speaker configuration may stress the power amplifier section and in extreme cases may lead to valve and/or output transformer failure.
HINTS & TIPS
Factory Reset
This will erase all the MIDI presets and set MIDI reception channel to #1. Please note that once the memory is erased it cannot be recovered.
Switch the amplifier off (power switch off, not standby switch).
Press and hold CLEAN/CRUNCH CHANNEL switch.
Switch the amplifier on (power switch on, not standby switch).
The 2 channel LEDs will glow red.
Release the switch.
To confirm the factory reset press OVERDRIVE MODE switch.
If you want to abort, press any other switch.
Footswitch Reset:
It is possible to reset the footswitch to the factory default status. This is achieved as follows:
Unplug the footswitch at any of the cable sides.
Press and hold the switch #4 (right switch).
Plug in the footswitch cord.
Release the switch and the FX led will start blinking.
If you want to erase the footswitch memory press the switch #3. To keep the memory press either the #1 or #2 switch. Please note that once the memory is erased it cannot be recovered.
Release the switch and the footswitch will synchronise with the amplifier.
The factory default is as follows:
FSW #1: Clean/Crunch Mode
FSW #2: Overdrive Mode
FSW #3: Master
FSW #4: Reverb
Hints
Hint 1: It is possible to use different modes in the same channel with different volumes to avoid imbalance between mode levels. To do this simply create 2 presets in the footswitch assigning MASTER 1 or MASTER 2 to any of the modes.
If you do not connect any effect to the
SERIAL / PARALLEL FX LOOP the MIX control can be used to act like an extra volume control in any of the channels.
Hint 2: To have a tuner output muting the amplifier, connect the tuner to the FX send and select the Clean channel. Turn the MIX control to WET and switch the FX loop on. Store this preset as described before and label it for example as ‘tuner’. Obviously in this configuration it is not possible to connect any other effect to the loop.
Hint 3: To use a different preamplifier and combine it with the JVM channels, connect the external preamplifier output to the parallel loop return and turn the MIX to WET. Connect the external preamp input with a splitter to the amplifiers input (it might be necessary to use an active splitter to keep a high impedance and/or an isolated one to avoid ground loops). Switching the effects loop ON and OFF will alternate between the external preamp and the JVM preamp.
As the JVM reverb circuitry is connected after the parallel loop it is also possible to create a preset to add reverb to the external preamp. To do this, simply switch the reverb ON and create a preset in any channel with the reverb ON and FX ON and assign it to the footswitch. That would be external preamp + reverb.
You can also go further and assign a different Master level to both external and internal preamplifiers in the same way as you assigned reverb.
Hint 4: Notes about using 2 heads simultaneously. The suggested procedure is connect the ‘master’ head PREAMP OUT to the ‘slave’ head POWER AMP IN and switch the POWER AMP INSERT to ACTIVE in the ‘slave’ amplifier.
In order to track the master volume settings in both heads (as the master volume circuitry is wired after the loop) it is suggested to use MIDI control with both amplifiers programmed in the same way. Connect the MIDI IN of one of the amplifiers to the MIDI THROUGH of the other and the pedalboard or MIDI equipment to the remaining MIDI IN.
ENGLISH
8 | 9 |
