I purchased a first generation Boss Katana KTN-100 watt amplifier in 2019, and have used it for rehearsals, live performances, and recordings with much success. The amplifier has great features in a compact and lightweight package. Although line out recordings always sounded great and live clean tones were reasonably good, higher gain settings always seemed lifeless, fuzzy, and lacking in sound coloration and depth.I considered replacing the amp with a new Boss Katana Artist Mk II, but noted other owners reported significant sound improvement by replacing the original 12” speaker.I have used Celestion speakers for over 50 years and found this Celestion Hot 100 8 Ohm replacement for a very reasonable price. The Hot 100 speaker weighs approximately 2 pounds more due to a significantly larger magnet and thicker cone material than the stock Boss speaker.Replacement was a relatively simple 10 minute process, although Boss uses a half sized negative connector that requires using a heavy duty wire cutter to separate the end of the speaker’s negative full size spade connector.I followed Celestion’s speaker break in process by playing a guitar chording phrase recorded on a looper for 10 minutes using clean moderate settings and another 10 minutes with maximum bass and mid range settings, and finally some higher gain settings.The Hot 100 speaker completely transformed the Katana KTN-100’s tone with significantly more definition, overtone and harmonic coloration, transparent clean tones, and soaring, beefy, and manic high gain sounds. For years I struggled to obtain stronger tonal sounds without applying significant noise reduction to reduce fizzing and crackles while smothering patch tonal qualities.This new speaker unleashed the Katana beast, and I wish I had replaced it years ago. The Hot 100 speaker is a perfect replacement as it completely matches Boss Katana 100 amplifier specifications and outperforms the original Boss speaker by many miles. It also saved me $500 dollars on purchasing a new amplifier, as my original Katana now provides the sound I was seeking for a very nominal cost and effort.