Petka 85 86 88 Activation Thread Requirement Better High Quality Jun 2026

| | Type | Primary Use | | -------- | -------------------- | ---------------------------------------------- | | EF85 | Variable‑μ pentode | RF/IF amplification in AM/FM receivers | | EF86 | Low‑noise pentode | Audio preamplifiers, microphone amps, phono stages | | EF88 | High‑power pentode | Output stages in Hi‑Fi power amplifiers |

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