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9. Line Out XLR and Lift/GND Button
This output allows the user to connect the DynaBlock 400’s preamp directly to a mixing
console when performing live or recording in the studio. Use a standard XLR mic cable or
an XLR female to a 1/4-inch TRS patch cable depending on the mixer’s available inputs (it is
usually best to use a 1/4-inch TRS line-level input on the board to match gain levels). In the
Lift setting, the button disconnects Pin 1 of the XLR to help reduce ground loop hum when
routing signals directly to other equipment or mixing consoles. However if ground loop hum is
not audible, you may get superior shielding from outside noise sources with the button in the
GND setting.
User Tip: When using the XLR Line out for recording direct-to-computer, we would
recommend you insert a suitable device between the amp and computer such as A.R.T.’s
TubeMP with USB for extra gain control and USB conversion.
10. Line Out EQ Switch
This feature routes the preamp signal destined for the balanced Line Out XLR either through the
amp’s tone control and Scoop circuits, or around them. Depress the button (Post-EQ setting)
to have the same sound as your amp going to the PA or recording mixer, or leave it in the out
position (Pre-EQ setting) to send the instrument’s original, non-EQ’d signal to the board.
11. Effects Send and Return ¼ --inch Jacks
External effects processors can be connected here and are provided with a balanced post-EQ
signal from the Effect Send jack. The balanced Return jack is used to return processed audio
signals back into the DynaBlock 400. Using balanced or unbalanced shielded cables, simply
connect the Send to the input of your effects unit or pedal board, and the Return to its output.
User Tip 1: Although this is a balanced loop, you can connect unbalanced pedals with regular
guitar cords. However you should probably not mix balanced and unbalanced devices in this
or any effects loop.
User Tip 2: When not in use for patching-in effects, the Efx Send jack can alternatively be used as
an extra line-level output perhaps for driving an additional amplifier or power amp and speaker.
12. Phones Jack
Connect headphones here for practicing or recording. When you plug phones in, you mute the
amplifier’s speakers, however the XLR Line Out, Tuner jack and Efx Send jack will still work.
13. Speaker Outs
All speaker outputs – two combi 1/4-inch / Speakon™ jacks – are in parallel. The amp’s
minimum load is 4 ohms overall (not per-jack) therefore you can connect a total of one
4-ohm speaker cabinet, or two 8-ohm speaker cabinets, or four 16-ohm speaker cabinets to
the DynaBlock 400 head. You can use either a ¼” or Speakon connectors in both jacks.
User Tip 1: The DynaBlock 400 combo’s internal speaker load is 8-ohms therefore any
extension cabinet should be no less than 8-ohms. (DynaBlock Combos only)
User Tip 2: The 400-Watt @ 4-ohms rated power output is measured with the amp’s Gain,
Master and tone controls adjusted for minimal distortion. When shopping for a single 4-ohm
cabinet to use with the DynaBlock 400 head, look for one with a program power rating of
approximately 500 Watts to provide some added capacity for handling “crunch” distortion.
Alternatively you could employ two 250-Watt (program) 8-ohm cabinets.
User Tip 3: Most speaker cabs with dual jacks have them wired together in parallel. When
pairing two such cabinets with the DynaBlock 400 head, you only need to use one Speaker
Out, and then patch the cabs together. However if you prefer to run 2 cables, each from one of
the amp’s Speaker Outs, that would work equally well (it’s really all the same thing, electrically).
14. Tweeter Defeat/Active Switch
(DynaBlock400 Combos only)
In the Defeat position, this switch disconnects the internal tweeter for a softer, more classic
bass amp tone. For more brightness set it in the Active position.
