From the web:

Onkyo T-4500 (1989, $320)
The T-4500, a black digital FM-AM tuner. The T-4500 has the equivalent of 5 gangs and 4 ceramic filters, 2 of which are used in Wide mode and all 4 of which are used in Narrow mode. Our contributor Stephan notes that the T-4500 and the T-4650, a European model that appears to be identical to the T-4500 except for voltage and tuning increments, use the Sanyo LA3401 MPX chip, and the Sanyo LA1266 IF limiter/mute/metering IC for the quadrature detector function. Our panelist Jim did a Shootout and offers this general information about the T-4500: "You like buttons? We've got buttons! This tuner is a button pusher's dream. I counted 41 and that's without considering that the 20 presets become 40 with the shift button. One button I used a lot during my DX tests was the cable/mute button, which also changes the tuning steps from .5 to .25 MHz. Functions are defeatable but when you change stations, the mute can activate. There is an 'APR' (automatic precision reception) button that chooses the best reception parameters. It, too, can be defeated per the operator's needs. The T-4500 has wide and narrow bandwidths and a local/DX RF mode. Also included is a manually selectable high blend and manual/auto tuning switch. This model takes a push-on (quick-connect) 75-ohm connection - a screw-on F-connector won't fit." Try Radio Shack catalog #2780291, if still available.

The T-4500's "Classified Memory Scan System" allows one to group preset stations into six "classes." Like many Onkyos, the T-4500 has excellent selectivity even in stock form, largely because two of its four ceramic filters have a narrow 150 kHz bandwidth. The wide filters, with a 230 kHz bandwidth, are first and last in the circuit (X101 and X104), while the two narrow filters, with a 150 kHz bandwidth, are in the middle (X102 and X103). The T-4500 would be a good tuner for a DXer or anyone in an urban area with strong signals. Our contributor Stephan compared his T-4500 to a Kenwood KT-880D: "For tougher (more crowded) receiving conditions, I'd prefer the T-4500, since it features one more gang, one more IF filter and a nifty channel separation correction circuit for narrow IF mode (simple but effective; look out for Q202)." Stephan also speculated, "On strong signals, the Kenwood with its nominally lower distortion LA1235 (instead of the LA1266 as used in the T-4500) may sound better, though that's probably more a matter of alignment."