So you’ve got passive speakers and need an external amplifier. Awesome. But it’s not as simple as just connecting the cables, turning the dials to 11 (see Spinal Tap) and walking away. There’s different modes to choose from and they all have different impacts; like how many speakers you can use, how much wattage of output power you get, how you need to run cables into and out of your amp, etc. For the sake of consistency, let’s assume for the rest of this post that we’re using a 2-channel Amplifier. Let’s start with Parallel Mode: Parallel mode allows you to run the amp in Mono. You send an output from your mixer to Input 1 (channel 1) on your amp and the amp internally routes the same signal to Channel 2 as well. Benefits of Parallel Mode: - Convenient Cabling: You don’t need a Y-cable or multiple outputs to send the same signal to both channels; the amp does this for you. - More Speakers: You can run more speakers in a chain. Because you’re running a single signal to both channels, you effectively double the total capacity for your speakers. Just make sure to do the impedance calculations for amp safety. - Fewer Amps Needed for One Output: When you have a lot of speakers in line with each other and you’re okay with only being able to control independent channel levels on your amplifier (I.e., not your mixer), this is a great option to cut down on the number of amplifiers you need. - Higher Volume: Reduces total impedance, allowing the amplifier to deliver more current and power. - Redundancy: Signal is not linear in the chain. If one speaker fails, the others continue to function. - Sound Quality: Better for speakers with internal crossovers (like 2-way Hi-Fi speakers) as it maintains correct frequency response. Cons of Parallel Mode: - Channel Loss: You can’t send different signals to each channel. - Too Few Amps for Many Outputs: If you have front fills, delay lines, and subs, you might not have enough amplifiers to afford to lose an entire differentiated channel. - Inconvenient Control: You don’t have independent control from the tech table/FOH position. You need to either walk over to the amp or have an A2 who can adjust levels for you. You do have independent amp channel control though, so you can adjust the level of one channel without affecting the other. - Potential Low Impedance: You have to be mindful of how low your impedance is getting: assuming speakers are all the same impedance, parallel mode calculations divide speaker impedance by the number of speakers in the chain (e.g., two 8 ohm speakers in a chain means impedance is 4 ohms - check the impedance rating of your amp and don’t go any lower than that. Most amps can only handle a minimum of 4 ohms (some can handle 2 ohms). - Higher Likelihood of Damage: If you fail to consider impedance implications in this mode, you can damage your amp/speakers. - Heat & Stress: The amplifier works much harder to provide more current, leading to increased heat.

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