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Summary of Contents for Kenwood BASIC M1
- Page 1 Kenwood BASIC M1 Audio Power Amplifier Current Source Modification www.drmaudioht.com...
- Page 2 This document intended for use by individuals experienced in electronics repair. ! ! ! CAUTION ! ! ! The power supply in the Kenwood BASIC M1 amplifier generates hazardous voltages that can cause electrical shock. The user of this document assumes all responsibility to follow safe practices to prevent shock or injury while making the modifications described in the document.
- Page 3 Kenwood BASIC M1 Current Source Modification Overview The Kenwood BASIC M1 uses a 56K resistor for a current source in the differential input stage. The configuration is known as a long-tailed pair. In the ideal world, the resistance of the current source resistor would be infinite.
- Page 4 Kenwood BASIC M1 Current Source Modification The V+ and V- leads of the LM334 are formed to have the same spacing as the original 56K resistor. The center lead is formed to allow a 150 ohm resistor to connect from the R lead to the V- lead.
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Page 5: Parts List
Kenwood BASIC M1 Current Source Modification Parts List The following table contains a list of parts included in the kit. Value Part # IC17 LM334z LM334z IC18 LM334z LM334z 150 ohm ¼ watt 5% resistor 3011151 150 ohm ¼ watt 5% resistor 3011151 500 ohm linear trim pot horizontal –... - Page 6 Kenwood BASIC M1 Current Source Modification Instructions Step 1 - Form the leads of the two LM334Z devices that are in a TO92 plastic case and solder a 150 1/4 watt carbon film resistor to the formed leads as shown in this photo: Note that the resistor is connected between the center lead, which is pin 2 of the device and pin 3.
- Page 7 Kenwood BASIC M1 Current Source Modification This photo shows the top side of the amplifier pc board assembly with the original current source resistor R18 removed: This photo shows the bottom side of the amplifier pc board assembly with the original current source resistor R17 removed: www.drmaudtioht.com...
- Page 8 Kenwood BASIC M1 Current Source Modification This photo shows the bottom side of the amplifier pc board assembly with the original current source resistor R18 removed: The first two set of photos are intended to assist in location of the resistors R17 and R18.
- Page 9 Kenwood BASIC M1 Current Source Modification This photo shows the top side of the amplifier pc board assembly with the original current source resistor R17 replaced by the LM334Z: IMPORTANT! Notice that the orientation of the devices is different for the left and right channel.
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Page 10: Support & Assistance
IMPORTANT While the Kenwood Basic M1 has speaker protection, it is imperative that speakers are not connected to the amplifier until it has been verified that the amplifier is operating correctly.