Amplifier Installation/How to Run HG Transistors

Congratulations on your decision to buy an amplifier! While installing it yourself can be rewarding, proper guidance is essential for success. Keep in mind that there is no one-size-fits-all approach due to variables such as the amplifier model, wiring, alternators, vehicle type, antennas, and your skill level. We are not responsible for your installation; it is entirely up to you. Following these guidelines can help you avoid issues, but unexpected problems can still arise. If you feel uncertain about your skills, we recommend seeking assistance from a professional radio shop in your area.

#### **Initial Considerations:**

1. **Check Your Vehicle's Alternator:**

   Ensure your vehicle's alternator can support the added power draw from the new amp. It's difficult to determine your car's baseline amp load since it fluctuates with the use of accessories like lights and air conditioning. Contact your car dealer to find out the baseline load your alternator can handle. The difference between this load and the alternator's output will determine how many amps are available for your system. Upgrading the charge wire from the alternator to the battery using a **4 AWG** or larger wire is recommended. Additionally, ground the alternator case to the chassis with a **4 AWG** wire.

2. **Power Requirements:**

   If you're adding an extra alternator dedicated to the new amp, a general guideline is to install an extra **100 amps** of alternator capacity for every **8 transistors** in your new amp, though this may vary depending on your setup.

#### **Preparing Your Vehicle:**

1. **Grounding:**

   Establish proper grounding throughout your system:

   - Ground the chassis to the battery with **4 AWG** wire for up to **500 watts** or **1/0** wire for over **500 watts**. Make sure to use finely stranded wire, such as welding cable. Clean all connection areas to bare metal before securing connections.

   - Ground the vehicle body, hood, trunk, and doors as necessary. Keep grounding straps or heavy gauge wires as short as possible (12 inches or less).

2. **Antenna Setup:**

   Adjust the antenna to achieve a Standing Wave Ratio (SWR) of **1.3:1** or lower on channels **1-40**. Ensure your antenna and coax can handle double the power you plan to transmit. High SWR can damage your amp and vehicle, so maintain it below **1.3:1** under load.

3. **Setting the DK:**

   Set your radio's dead key (DK) to **2 watts or less**. If you're uncertain how to do this, have a knowledgeable shop adjust it for you. Ideally, the DK should be set so that the amp outputs **10-15%** of its maximum rated PEP value under load.

#### **Installation Steps:**

1. **Wiring:**

   - Choose the appropriate wire gauge and fuse or breaker rated **25% higher** than needed for your application. Fuses should be placed directly at the battery.

   - Plan the routing of power wires carefully, avoiding interference with coax cables. Protect wires with a wire loom, and use grommets to prevent damage where wires pass through metal. Ensure any newly drilled holes in the firewall are de-burred and grommeted.

2. **Connecting the Amp:**

   - Use a multimeter to check for shorts before connecting power wires to the battery. 

   - After securing the amp, connect the power wires, ensuring you get the polarity correct. Connect the amp’s positive wire to the battery's positive and the ground wire to the battery's negative.

3. **Testing:**

   - With the amp off, check SWR from the radio to the amp and the amp to the antenna. If SWR exceeds **1.3:1**, diagnose the issue before powering up the amp.

   - Once SWR is confirmed to be **1.3:1** or less, connect the power wires to the battery and power on the amp. Look for normal operation indicators like lights and fans.

4. **Final Checks:**

   - After powering on, key the mic on channel 20 and listen for any unusual sounds. Ensure the amp un-keys properly, and check SWR again.

   - Perform a radio check with someone to verify audio clarity and functionality.

### **Conclusion**

These guidelines are intended to provide a basic framework for installing your amplifier and are not exhaustive. Many resources are available online from fellow DIY enthusiasts that can assist you further. Always prioritize safety while running your system.

Have fun with your installation!

### **Setting the Maximum Output from Your Amplifier**

As a general rule of thumb, set the **maximum output from your amp per transistor** (not input drive) to **25 watts dead key carrier per transistor**. Keep in mind that this measurement refers to the power coming out of the amplifier when keyed.

Here’s a quick reference for maximum dead key output based on the number of transistors in your amplifier:

- **2 Transistors:** 2 x 25 watts = **50W Dead Key Output**

- **4 Transistors:** 4 x 25 watts = **100W Dead Key Output**

- **6 Transistors:** 6 x 25 watts = **150W Dead Key Output**

- **And so on...**

This is the recommended maximum dead key output. While setting it lower will not cause any harm, exceeding these limits may place you in a risky operating zone.