FRONT PANEL CONTROLS

INPUT: This 1/4” [6.3mm] jack is the mono instrument INPUT, connect your bass (or mono source) here. The signal will be processed by the preamp and will be present at DI out, PREAMP OUT and SPEAKER OUT. Input impedance is 3.3 MOhm.

BYPASS: This switch bypasses the passive tone stack and changes the feedback circuit. You’ll experience a higher gain and a more hi-fi, open sound with less “tube-compression” flavor.

GAIN: This logarithmic pot controls how much of the first tube stage goes into the second tube stage. You can start around noon and turn counter-clockwise for a clean and fast sound or clockwise for a more fat sound. High gain settings result in a pleasant overdriven sound. The tube (1x12AX7) preamp circuit is fed by Jad Freer's switching power supply and it’s based on the iconic design of the B15, modded to their taste.

BASS & TREBLE: Jad Freer chose to use an old school passive design for the bass and treble EQ...this is traditionally referred to as baxandall or James style EQ and it's a popular style found in American tube amps. You can experience a “flat” curve when controls are around noon and then boost or cut frequencies. These controls operate on a very broad frequency range and sound very organic and musical. Use them without fear of messing with your tone.

MASTER: This logarithmic pot controls the overall volume of the SPEAKER OUT. Jad Freer tailored it to be useful in all its curve but beware: the Volta can be a very loud amp so start with a low setting.

STBY / POWER: Before plugging in the Volta check that the STANDBY and POWER switches are in the off (down) position. Start turning on (up) the POWER lever switch. You’ll see a blue LED light over the POWER switch and a red LED light over the STANDBY switch. In this setting the preamp is 100% working and the power amp is shut off, this makes silent recording operation possible because DI (pre and post) and PREAMP OUT are working.
When the STANDBY switch is in the ON (up) position, the red LED light becomes green and power is slowly given to the power amp section to fully operate the head.
While the Volta by itself can be safely fully on (green and blue lights on) without any cab connected, it's important to have a cab connected when playing and raising master volume. So Jad Freer suggests always checking for a connected cab before turning on the amplifier. Any damage to the output transformer due to mishandling is not warranty covered.

REAR PANEL CONTROLS

VOLTAGE SELECTOR: This switch allows the amp to be used with international voltages (115-230VAC). The amp is shipped to the new owner with the switch set to correspond with the US.
If you travel the world with your Volta please remember to set the switch to the right voltage BEFORE turning it on. The Volta is internally protected by a series of circuits designed for a safe operation, even from an event of voltage mismatch, but permanent damage - not warranty covered - could occur.

MAINS IN: Connect the provided power cable here. If your Country needs a different outlet plug use a high quality cable (1mm2 or 0.75mm2 core).

SPEAKER OUT: Connect your speakers here, using these combo outputs (1/4” jack- Speakon). Always provide open ventilation around the amp. Power rating is 200W.

OHM: Use this switch to select the TOTAL minimum impedance of the cabs connected to the amp. Do not mess with this control while the amp is powered on and sounding. (If you mix 8 and 4 Ohm cabs you get 2.6 Ohm so use the 2 Ohm setting)

PREAMP OUT: It’s driven from a dedicated triode (tube) that set the signal to be ready for pedals, effects units or a slave output to another amp or power amplifier

POWER AMP IN: Goes into another triode (tube) that raises the signal adding natural tube overtones.

D.I. OUT: (transformer balanced) This XLR output is fully balanced and it’s made by a solid state buffer driving a linear transformer. The kind of DI signal can be selected with a three position switch:
PRE: It’s the signal taken after the very first tube stage, so it’s not affected by GAIN or other controls.
POST: The signal it’s taken after the GAIN and EQ stages, before MASTER control.
AMP: Is for the signal taken after the output transformer so it carries the full sound of the amp.
DI volume can be fine tuned with a dedicated LEVEL pot on the back.

GND/LIFT: This switch eliminates or reduces unwanted hum or noise in the DI signal by interrupting the ground loops between equipment.

POWER TUBE OPERATION LEDS: Each LED is connected to a dedicated fuse and, if ON, indicates a fuse failure. There are four fuses, one for each power tube and two more for the high voltage sections of the amp.

TUBES: The Volta uses 3 x ECC83/12XA7 in the preamp section and 4 x KT88 tubes in the power amp section.