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Keiga Amplifiers

Keiga Class D Subwoofer Plate Amplifiers

Keiga KGND5250, 500 Watts
Keiga KGND52100
, 1000 Watts

Madisound is pleased to offer these powerful Class D amplifiers. A Class D amplifier is a switching amplifier that converts a low level analog signal into a high power pulse width modulated output. The KGND52100 is 86% efficient and the KGND5250 is 82% efficient; inherent in the Class D design and the efficient power supply. The 1950 watt peak analog power supply is a cleaner power source than switching power supplies found in most other Class D amplifiers. The Keiga Class D amps also have very low standby power consumption of 1 Watt, which meets new European standards. Because of its efficiency, these amps produce very little heat. The amps are equipped with a protective casing on the back, not shown in this picture.

  • Very high efficiency Class D amplifier; high current Mosfet output devices
  • Low pass frequency adjustable 50~100Hz
  • Woofer level control
  • 180° Phase invert switch
  • Auto on control, switchable
  • Very low standby power
  • Thermal protection
  • Master power switch
  • LFE input
  • RCA in/out (out has no crossover)
  • Speaker level in/out (out has no crossover)
  • IEC power socket
  • LED power indicator
  • AC 115V/230V switchable

Keiga KGND5250 500W Digital Plate Amplifier

500 Watts

Keiga KGND52100 (1000 Watt)

1000 Watts

Keiga Subwoofer Amplifiers

Keiga KG-5150, 200 Watts @ 4 Ohm
Keiga KG-5230
, 300 Watts @ 4 Ohm

The KG-5150 and KG-5230 are plate Subwoofer Amplifiers with Electronic Crossovers for building powered subwoofer systems. These amps have adjustable electronic crossovers and have enough power to deliver good bass without added distortion. We are confident that we now have products that can meet the demands of both home theater or high end audio systems. Powered subwoofers are a versatile addition to your audio system. With the variable crossover and volume control, you can match a subwoofer to any existing system. These amplifiers can be used with single or multiple woofer systems (a total impedance of 4 to 8 ohms is recommended). The crossover can be turned off if you are using the amplifier with a system that already has a built in crossover. KG5230 has a 12V DC trigger.

  • Class AB
  • Discrete high current drivers and output devices
  • Woofer volume control
  • 50Hz to 100Hz continuously adjustable low pass 12dB electronic crossover
  • Crossover on/off switch
  • Low and High level input, summed to mono signal
  • Low and High level all pass output
  • Phase inverter switch
  • Master power switch
  • Auto power on/off activated by input signal
  • 4dB boost @ 25Hz, 15Hz High pass

Keiga KG5150 (200 Watt) Keiga KG-5150
200 Watts

Keiga KG5230 (300 Watt) Keiga KG-5230
300 Watts

Keiga 2:1 Media Amplifiers

Keiga KG-3100, 50 Watts & (2x) 25 Watts @ 4 Ohm

The KG-3100 2.1 Amplifier was developed for small sub/sat systems. The amp is designed to be built into the subwoofer enclosure and then out to the satellite speakers. You can use the built in electronic crossover to divide the frequencies between the amp and the satellites. The electronic crossover is continuously variable from 75Hz to 150Hz. There is a master volume control and a volume control for just the subwoofer. The amplifier will accept either RCA inputs or 3.5mm Mini Jack inputs. If you are using the mini jack inputs, you can purchase a separate desktop volume control for use with your computer. The KG-3100 is the perfect choice to build a system for your computer, MP3 player, portable CD player, office or small apartment.

  • X-over LP + HP: 75Hz - 150Hz
  • Rear plastic cover
  • Master & woofer volume controls
  • Switchable bass boost 3dB@40Hz
  • Auto on control
  • GP Binding Posts for Sat. Outs

Consider purchasing: Keiga KG-VC Desktop Volume Control - Mini Jack

Keiga KG-3100 2.1 Media Amplifier (50W & 2x 25W) KG-3100
50 Watts & 2 x 25 Watts

Keiga KG-VC Desktop Volume Control - Mini Jack KG-VC
Desktop Volume Control - Mini Jack 


  KGND52100 KGND5250 KG-5230 KG-5150 KG-3100
Power output, Watt @ 4 ohm 1000 Watts 500 Watts 300 Watts 200 Watts 50 & 2x25 Watts
THD 0.08% 0.08% 0.08% 0.05% 0.08%
S/N ratio @ rated power 90dB 80dB 85dB 85dB 76dB
Input sensitivity @ 100Hz - low level 190mV 150mV 75mV 75mV 75mV
Input sensitivity @ 100Hz - high level 4.2V 3.5V 3.5V 3.5V 3.5V
Input impedance 22k ohms 22k ohms 22k ohms 22k ohms 22k ohms
Variable low pass crossover freq. 50-100Hz 50-100Hz 50-100Hz 50-100Hz 75-150Hz
Weight pounds 13.5 lbs 9.0 lbs 14.5 lbs 10.5 lbs 7.6 lbs
W x H
12" x 12"
12" x 12"
9-7/8" x
11-7/16" x
7-7/8" x
Cutout hole
W x H
11" x 11" 11" x 11" 8-7/8" x
10-7/16" x
6-7/8" x
AC Voltage 115V/230V
115V 115V/230V


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If you are unsure what you want to order, it is best to call and talk with a speaker tech. It has been our experience that almost every sale involves some form of consultation, and we are here to help.