Adcom GFP-555 II
Price trend
Sold or Listed Prices
12 market transactions via web search — not HiFi Registry sales.
Understanding the market
Half of recorded transactions fall between $249 and $400. The full range runs 3.8× from lowest to highest, which is normal for used equipment where condition, included accessories, and service history vary between units.
What buyers should know
Check whether the unit uses tubes or solid-state gain, and if tubes, when they were last replaced. Confirm all inputs switch cleanly and the volume control is free of channel imbalance at low levels, which is the most common wear point.
This range reflects 12 recorded sales, compiled from publicly listed and completed sales elsewhere on the used market, not from HiFi Registry transactions. That is a large enough sample to price against with reasonable confidence, though condition and provenance still move individual units.