Adcom GTP-500

Price trend

Sold or Listed Prices

20 market transactions via web search — not HiFi Registry sales.

Understanding the market

Half of recorded transactions fall between $179 and $400. The full observed range is unusually wide — the highest recorded price is 10.7× 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 $303 across 6 recorded sales, 14% higher than the preceding twelve months.

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 20 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.