Impedance matching
Impedance matching ensures your amp and speakers (or amp and headphones) work together efficiently. Speaker amp: check the amp handles your speaker's impedance (typically 4Ω or 8Ω). Headphone amp: check output impedance is at least 8x lower than headphone impedance for accurate frequency response.
Impedance matching in hi-fi means picking components whose impedances are compatible for clean, accurate reproduction.
Speaker amp matching
Amp specs say “150W at 4Ω” or “75W at 8Ω”. A 4Ω speaker on an 8Ω-only amp can force the amp into protection mode. Most modern Class-D amps like the TPA3255 handle 4-8Ω without issue.
Headphone amp matching
Rule: amp output impedance should be at least 8x lower than headphone impedance. A 300Ω headphone wants an amp with output impedance below 37Ω. Higher output impedance dampens the frequency response (headphone-dependent bass rolloff or peak).
Line-level matching
DAC output ~2 Vrms, amp input ~10 kΩ. Standard consumer levels match. If preamp output is very hot (5V+), some amps may overload.
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