Ampeg SVT-150H Bass Amplifier User Guide

Owner’s Guid
SVT-150H
Bass Amplifier
Made in the U.S.A.

Introduction

An Introduction to your new Ampeg SVT-150H Bass Amplifier
First of all, thank you for making what could be one of the best choices you could ever make concerning your musical career – choosing one of the finest bass amplifiers available, an Ampeg SVT-150H.
Your new bass amplifier offers you many outstanding features, such as 150 watts of pure bass energy, total tone control and rugged construction which make it a true performer’s bass amp.

Features

In the world of high performance bass amps, Ampeg amplifiers stand alone. In true Ampeg tradition, your new SVT-150H offers you more power, performance and flexibility than any other bass amplifier in its class. Here are just some of the outstanding features of your new amplifier – features which set it apart from the competition!

• 9-BAND GRAPHIC EQ: Use as a “second channel” for bass solos, or to shape your sound to your own exacting standards.
• BALANCED LINE OUTPUT: XLR with independent level control switch to patch into house consoles, mixing boards, or external power amplifiers.
• EFFECTS LOOP: For increased intensity and quieter operation of external effects.
• DRIVE CONTROL: To add harmonic content for tube-like overdrive.

Important Safeguards and Precautions

All Ampeg products are designed for continuous safe operation, as long as common sense is used and steps are taken to help avoid certain problems. Abiding by the following rules can help prevent damage to your amplifier, yourself and others.

• The amplifier is equipped with a three-pronged AC power cord. To reduce the risk of electrical shock, NEVER remove or otherwise attempt to defeat the ground pin of the power cord.
• Connect the amplifier ONLY to a properly grounded AC outlet of the proper voltage for your amp.
• Avoid sudden temperature extremes, rain and moisture. Also, avoid sudden and intense impact. (If the unit has been subjected to any of the preceeding abuses, have it looked at by an authorized service center.)
• NEVER set the amplifier on a support that might give out under its weight.
• Always keep the total speaker impedance at or above the rated load.
• Unplug the amplifier before cleaning it. NEVER spray liquid cleaners onto the amplifier. Wipe it with a slightly dampened, lint-free cloth to remove dirt and film.
• Don’t use the amplifier if it has sustained damage to the chassis, controls, or power cord. Refer the unit to an authorized service cen- ter for inspection.
• Amplifiers capable of producing high volume levels are also capable of inflicting permanent hearing loss or damage, if the exposure to such levels is prolonged. Such damage is progressive and irreversible!

THIS EQUIPMENT HAS BEEN DESIGNED AND ENGINEERED TO PROVIDE SAFE AND RELIABLE OPERATION. IN ORDER TO PROLONG THE LIFE OF THE UNIT AND PREVENT ACCIDENTAL DAMAGES OR INJURY, PLEASE FOLLOW THESE PRECAUTIONARY GUIDELINES:
WARNING: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT OPEN CHASSIS; DO NOT DEFEAT OR REMOVE THE GROUND PIN OF THE POWER CORD; CONNECT ONLY TO A PROPERLY GROUNDED AC POWER OUTLET.
CAUTION: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
CAUTION: NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
CAUTION: OUR AMPLIFIERS ARE CAPABLE OF PRODUCING HIGH SOUND PRESSURE LEVELS. CONTINUED EXPOSURE TO HIGH SOUND PRESSURE LEVELS CAN CAUSE PERMANENT HEARING IMPAIRMENT OR LOSS. USER CAUTION IS ADVISED AND EAR PROTECTION IS RECOMMENDED IF UNIT IS OPERATED AT HIGH VOLUME. The chart below shows the U.S. Government Occupational Safety and Health Administration (OSHA) regulations which were in effect at the time of this publication for permissible noise exposure, per 29CRF1910, Table G-16.

According to OSHA, any exposure in excess of those listed above could result in some hearing loss.
EXPLANATION OF GRAPHICAL SYMBOLS:

| “DANGEROUS VOLTAGE”
“DANGER HAUTE TENSION”
“GEFAHLICHE SPANNUNG”
---|---
| “IT IS NECESSARY FOR THE USER TO REFER TO THE INSTRUCTION MANUAL”
“REFERREZ-VOUS AU MANUAL D’UTILISATION”
“UNBEDINGT IN DER BEDIENUNGSANLEITUNG NACHSCHLAGEN”

The Front Panel Controls and Their Use

1. INPUT: Connect your bass guitar here using a shielded instrument cable.

2. -15dB PAD: If your bass has high-output pickups or active electronics you may notice the Peak LED (#3) flashes or stays on even at low settings of the Gain control (#4). To keep the signal clean, switch in the Pad. This will attenuate the input signal to the preamp allowing you to get the best signal to noise ratio for your bass.

3. PEAK LED: This LED lights whenever any preamp stage is near the point of being overdriven. Adjust the Gain control (#4) until a strong signal from your bass causes this LED to licker.
   NOTE: If the LED stays on with the Gain at a low setting, use the 15dB Pad (#2) to attenuate the input signal and readjust the Gain.

4. GAIN: This serves as the input level control for the amplifier. For the best signal-to-noise ratio set this control so the Peak LED (#3) flashes when you strike a string fairly hard.

5. DRIVE: This control is used to overdrive the preamp in order to get various harmonic enhancement or distortion sounds. In the fully counterclockwise position the preamp is in the cleanest condition. As the control is rotated clockwise, signal level is increased to drive the preamp harder (into distortion). The tone of the signal is also changed to provide a smoother overdrive. The tone controls may have to be readjusted to obtain the overall desired tone. The Gain control (#4) and -15dB Pad (#2) interact with the Drive control. For greater overdrive, the Pad switch should be out and the Drive control fully clockwise. Use the Gain control to set the amount of overdrive desired. The Peak LED (#3) will glow steadily when the amp is used in this manner.

6. BASS: This knob serves as the primary low frequency control. This allows for a range of 8dB of cut or boost at 50Hz.

7. ULTRA-MID: This is the primary midrange control. Rotate the control to the left of center for a “contoured” sound (more distant, less midrange output) or to the right of center for a sound that really cuts through.

8. TREBLE: This knob serves as the primary high frequency control. This allows for a range of 17dB boost or 22dB cut at 5kHz.

9. EQ ON LED: This LED indicator lights when you engage the EQ by the front panel Master control (#11) or the footswitch (#23, rear panel).

10. GRAPHIC EQ: These slide controls allow you to adjust the output of the frequencies shown beside each control. The center position of each control is flat (no boost or cut). These controls only affect the sound when the EQ is turned on.

11. MASTER: Set the overall output level of the amplifier with this control. The Effects Loop and Balanced Out (#18, 19, 22) are not affected by the Master control. Pulling the Master control turns on the Graphic EQ (#10). When the footswitch is used, the front panel switch is bypassed.

12. LIMIT LED: This LED indicator will flash on any time the internal limit circuit is called upon to keep amplifier’s output signal clean. This indicates that the amplifier is nearing full output and the limiter is keeping it from clipping the output signal.

13. POWER ON LED: This LED indicator lights when the POWER switch (#14) is turned on.

14. POWER SWITCH: This heavy-duty rocker switch applies AC power to the amplifier: the amp is ON in the up position, OFF in the down position.

The Rear Panel

15. FUSE: This protects the unit from damage due to overload conditions or power line surges. If the fuse blows, replace it only with the same size and type.
16. AC LINE IN: Firmly plug the supplied AC power cord into this socket, pushing it in until it is fully seated. Plug the male end of the cord into a grounded AC outlet. DO NOT DEFEAT THE GROUND PRONG OF THE AC PLUG!
17. SPEAKER OUTPUT(S): The SVT- 150H has two 1/4” speaker output jacks which you will use to connect to your bass cabinet(s). Use speaker cables with 1/4” plugs to connect the SPEAKER jack(s) to the cabinet(s). Observe the 4 ohm minimum impedance rating. Please see the note concerning the speaker output jacks on the facing page.
    The following chart shows the total impedance load when connecting speaker cabinets in parallel:

18. EFFECTS RETURN: To use an external effects device or other signal processor, connect the OUTPUT of the device to this jack using a shielded cable. This feeds the processed signal into the amplifier’s master section.
19. EFFECTS SEND: Connect the output from this jack to the INPUT of an external effects device using a shielded cable. This sends a post-EQ signal to your effects. Since plugging a cable in here does not break the through connection to the power amp, this can be used as another line out.
20. PRE/POST SWITCH: You can select either pre or post-EQ for the signal at the Balanced Out jack (#22) with this switch. With the switch in the OUT position, the signal at the jacks will be pre-EQ. This is a direct output which is not affected by any EQ or boost settings. With the switch in, the signal is post-EQ and is controlled and modified by the tone controls, Graphic EQ and Effects Loop.
21. -20dB SWITCH: This switch adjusts the output level at the Balanced Out jack (#22). The switch works independently from the front panel Master control. Pushing the switch in activates the -20dB pad, allowing patching into microphone inputs on a mixer without overdriving them.
22. BALANCED OUT: This XLR-type connection supplies a balanced preamp output signal for connecting to a house mixing board, recording console or external amplifiers with balanced inputs. The signal can be set to pre or post-EQ by the Pre/Post switch (#20). The level can be adjusted for either mic or line type inputs using the -20dB switch (#21).
23. FOOTSWITCH: This jack accepts the 1/4” plug from a 1-button footswitch, allowing remote control of the Graphic EQ on/off function. When a footswitch is used, the front panel Master Pull EQ On switch (#11) is bypassed.

NOTE: In some areas 1/4” speaker jacks are not acceptable for use on amplifiers capable of high output power levels. For this reason the Speaker jacks on your amplifier may resemble the illustration to the right. Connect the amplifier to your speaker(s) using cables rated for very high output power, terminated with the appropriate connectors.

Some Suggested Settings
The setting of the Gain control depends on your particular instrument. The Master should be set to produce the appropriate output volume level. The Graphic EQ can be used to tailor the amplifier to your speaker cabinets, to compensate for room acoustics and to “fine tune” your sound.
ROCK:

JAZZ:

COUNTRY:

FUNK “POPPING:”

Troubleshooting

In the unlikely event that you SVT-150H should stop working properly (or just stop working), take a few minutes to troubleshoot it before you call for service. You can save yourself a lot of time and sometimes money by doing it yourself, and often the cure for the problem is something quite simple.

If the problem isn’t covered above, or if the steps led you here, then contact your Ampeg dealer for service information. Also, you should refer your amp for servicing if it gets dropped, has liquid spilled into it, or sustains damage to its power cord (see page 2).

System Block Diagram

Technical Specifications

POWER REQUIREMENTS
Domestic:
Export:| 115VAC, 60Hz, 140VA
100/115VAC, 50/60Hz, 140VA
230VAC 50,60Hz, 140VA
TONE CONTROL RANGE
Bass:
Ultra-Mid:
Treble:| ±8dB @ 50Hz
+5, -17dB @500HZ
+17, -22dB @ 5KHZ
GRAPHIC EQ RANGE
40Hz
80Hz
150Hz
300Hz
600Hz
900Hz
2kHz
5kHz
9kHz| ±11dB
±8dB
±8dB
±8dB
±8dB
±8dB
±8dB
±9dB
±12dB
GAIN| 66dB typical, tones @ center
SIGNAL TO NOISE RATIO| 75dB typical
SIZE (W x H x D) AND WEIGHT| 19”x9.5”x12.5”, 30 lbs

Ampeg reserves the right to change specifications without notice.
Ampeg is proudly Made in America.
©1997 SLM Electronics, 1400 Ferguson Avenue,
St. Louis, MO 63133 U.S.A.
P/N 47-588-52
01/97

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