Adcom GFA-555 II
Price trend
15 months of data shown — Listing Comps build richer history as transactions accumulate.
Sold or Listed Prices
15 market transactions via web search — not HiFi Registry sales.
Understanding the market
Half of recorded transactions fall between $400 and $600. The full observed range is unusually wide — the highest recorded price is 15.7× the lowest. A spread that wide usually means the recorded sales are not strictly comparable: different configurations or finishes, units sold for parts or with cosmetic damage, or listings where the model name is shared across more than one variant. Treat the middle range as the useful signal and the extremes as outliers worth investigating before you price against them.
Over the last twelve months this model averaged $501 across 13 recorded sales, 8% higher than the preceding twelve months.
What buyers should know
Ask when the unit was last serviced and whether the output devices are original. Bias and DC offset drift with age on solid-state amps. Confirm both channels have been tested under load, not just powered on.
This range reflects 15 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.