V-4B Bass Guitar Amplifier + 0 ULTRA LO 1 220 HZ 2 8OO HZ 3 3OOO HZ + 0 ULTRA HI SS EQUALIZATION TDSK CUT 0 dB -15 dB GAIN BASS MODEL V-4B BOOST MIDRANGE TREBLE MASTER Owner’s Manual STANDBY POWER
V-4B Bass Guitar Amplifier TABLE OF CONTENTS Important Safety Instructions..................................................2 Introduction / Features...........................................................4 The Front Panel.....................................................................5 The Rear Panel......................................................................7 Important Information About Tubes..........................................9 Troubleshooting / Block Diagram......................
V-4B Bass Guitar Amplifier NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.
V-4B Bass Guitar Amplifier Introduction Congratulations on your purchase of the Ampeg V-4B 100W all-tube bass head. Based on the original from 1971, the Ampeg V-4B 100W all-tube head embodies the legendary tone of the classic V-4B in a tough-as-nails package, ready to take the stage with the flexible output control and pure vintage Ampeg grind you crave at volume levels ideal for modern venues and applications.
V-4B Bass Guitar Amplifier The Front Panel 4 + 0 ULTRA LO 5 1 220 HZ 6 2 800 HZ 3 3OOO HZ 11 + 0 ULTRA HI EQUALIZATION MODEL V-4B CUT BOOST 0 dB -15 dB GAIN BASS MIDRANGE TREBLE MASTER STANDBY POWER 1 2 3 7 8 9 10 12 13 1. 0 dB INPUT: The signal output from a passive instrument may be connected to this 1/4" input by means of a shielded instrument cable. 2.
V-4B Bass Guitar Amplifier The Front Panel continued... 4 + 0 ULTRA LO 5 1 220 HZ 6 2 800 HZ 3 3OOO HZ 11 + 0 ULTRA HI EQUALIZATION MODEL V-4B CUT 0 dB -15 dB GAIN BASS MIDRANGE TREBLE MASTER STANDBY POWER 1 2 3 7 8 9 10 12 13 11. STANDBY/POWER LED: This is a multi-function LED. In Standby mode, it glows red and in the On mode it glows green. 12. STANDBY SWITCH: Use this switch to turn the standby power on or off. Press the top of the switch to turn the standby on.
V-4B Bass Guitar Amplifier The Rear Panel TUBE COMPLEMENT: MODEL V-4B POWER CONSUMPTION 100W POWERAMP 6L6 PREAMP 6L6 6L6 12AX7 CAUTION RISK OF ELECTRICAL SHOCK DO NOT OPEN FUSE: FOR 100V-120V FOR 220V-240V :T4A H 250V :T2A H 250V AVIS: RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR.
V-4B Bass Guitar Amplifier The Rear Panel continued... TUBE COMPLEMENT: MODEL V-4B POWER CONSUMPTION 100W POWERAMP 6L6 PREAMP 6L6 6L6 12AX7 CAUTION RISK OF ELECTRICAL SHOCK DO NOT OPEN FUSE: FOR 100V-120V FOR 220V-240V :T4A H 250V :T2A H 250V AVIS: RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR.
V-4B Bass Guitar Amplifier Important information about tubes A brief history of the tube: In 1883, Thomas Edison discovered that electrons would flow from a suspended filament when enclosed in an evacuated lamp. Years later, in 1905, John Ambrose Fleming expanded on Edison’s discovery and created the “Fleming Valve”. Then, in 1907, Dr. Lee de Forest added a third component – the grid – to “Fleming’s Valve” and the vacuum tube was a fact of life. The door to electronic amplification was now open.
V-4B Bass Guitar Amplifier Tube types and usage continued... Power tubes are the largest tubes used in an amplifier, generate the most heat and wear out the fastest. These tubes convert the low-level, conditioned signal from the preamplifier into a level that is sufficient to drive the speakers. There are several types of power tubes available, each of which offers a different performance/sound characteristic. For example, the EL34 power tube produces a great classic rock sound.
V-4B Bass Guitar Amplifier The nature of tubes continued... Whenever replacing power tube(s): • Always have the amplifier’s bias voltage checked by a qualified service center. Improper bias voltage will cause degradation in performance and possibly damage tubes and/or the amplifier. (See the section below titled “The importance of proper biasing” for more information on this subject). • We highly recommend replacing the driver tube(s), as well.
V-4B Bass Guitar Amplifier Survival Tips for Tube Amplifiers To prolong tube life, observe these tips and recommendations: • Match the impedance of the speaker cabinet(s) to the amplifier. Improper impedance matching will contribute to early tube degradation and may cause premature tube failure. • Make sure the speaker(s) are properly connected prior to turning on the amplifier. • After playing the amplifier, allow sufficient time for it to properly cool down prior to moving it.
V-4B Bass Guitar Amplifier Changing the Tubes Tubes wear out in direct proportion to how often and how hard you use the amplifier. Power tubes should be checked at least once a year – more frequently if you use the amplifier nearly every day. When power tubes wear out, the amplifier will begin to grow weak, lack punch, fade up and down, or lose highs and lows. Power tubes work together in a push/pull configuration and should be replaced at the same time with matched or balanced tubes.
V-4B Bass Guitar Amplifier Troubleshooting In the unlikely event that your V-4B should malfunction, take a few minutes to troubleshoot it before you call for service. You can save yourself time and money by doing it yourself, and often the cure for the problem is something quite simple. If you think the problem may be worn out tubes, see page 10–11 for symptoms of tube failure. If the problem isn’t covered above, or if the steps lead you here, then contact your Ampeg dealer for service information.
V-4B Bass Guitar Amplifier V-4B TECHNICAL SPECIFICATIONS Preamp Tube Driver Tube Power Amp Tube 2 x 12AX7 1 x 12AX7, 1 x 12AU7 4 x 6L6GC Output Power Rating 100W @ 8% THD+N @1 kHz for 2, 4 or 8 Ω loads Signal to Noise Ratio 80 dB @ 1 kHz (20 Hz–20 kHz, unweighted) Maximum Gain 64 dB @ 1 kHz, tones centered -3 dB @ 14 Hz and 15 kHz Tone Controls Bass: +13/–12 dB @ 40 Hz Midrange: +11/–21 dB @ 220 Hz, 800 Hz, 3 kHz Treble: +14/–17 dB @ 4 kHz Ultra Lo: +2 dB @ 40 Hz, -11 dB @ 500 Hz
B4 -V reifilpmA ratiuG ssaB TUBE COMPLEMENT: MODEL V-4B POWERAMP 6L6 PREAMP 6L6 12AX7 6L6 CAUTION POWER CONSUMPTION 100W FUSE: FOR 100V-120V FOR 220V-240V :T4A H 250V :T2A H 250V 12AU7 6L6 12AX7 BALANCED OUT RISK OF ELECTRICAL SHOCK DO NOT OPEN AVIS: RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR. WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REMOVE COVER. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
