How to adjust the brightness of a spot amplifier
Simply (as shown) insert a 120pF silver mica cap (15 cents!) between the first two lugs of the volume pot. The most direct way to make your amp sound brighter is by adjusting the EQ settings. My darkest sounding cabinets are the best balances, such as my 4x12 full of EVM-12Ls, and yes, those ARE relatively dark speakers compared to some. Let's get started by looking at what these little caps do, why they are there and how you can swap them with different values to help tweak your amp the way you like it. Optimal brightness calibration (without using any hardware modifications) maximizes cathode bias voltage, minimizes G1 bias voltage, and maximizes G2 bias voltage. This article provides a detailed examination of how to adjust an amplifier and outlines the key points for achieving ideal sound.
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