Onkyo TX-2500MKII (1978–1981)
A late-1970s stereo receiver with advanced tuner features and a 1978-era redesign. Build is strong and the sound is well regarded.
Overview
The Onkyo TX-2500MKII is a stereo receiver produced from 1978 to 1981. It is the second model in a four-receiver Onkyo lineup from that period. Onkyo placed it in the mid-to-high tier, with better preamp and tuner specs than earlier versions and more output power. It is known for the "Accutouch" tuning system, a PLL MPX decoder and a servo-locking tuner. You tune by hand, and once you let go, the tuner fine-tunes itself. Owners describe it as an excellent-sounding, underrated receiver that often compares favorably to contemporary models from Marantz and Pioneer.
Specifications
| Years of manufacture | 1978 - 1981 |
| Original price | $450 |
| Power Output | 2x 100W (DIN) |
| THD | 0.5% at rated power |
| IMD | 0.5% at rated power |
| Damping factor | 40 (8 Ohm, 1 kHz, 10W output) |
| Power bandwidth | 2 Hz ... 60 kHz (± 1 dB) |
| Frequency response | 20Hz to 30kHz |
| Bass control | ±12 dB at 100 Hz |
| Treble control | ±10 dB at 10 kHz |
| High filter | 6 kHz |
| S/N ratio | 85 dB |
| Tuning range (FM) | 87.5–108 MHz |
| Tuning range (AM) | 530–1605 kHz |
| Usable sensitivity (FM) | 2 µV (mono) |
| IF frequency (FM) | 10.7 MHz |
| Capture ratio | 2 dB |
| Image rejection (FM) | 45 dB |
| IF rejection (FM) | 80 dB |
| Adjacent channel attenuation (FM) | 60 dB |
| Stereo separation (1 kHz, FM) | 37 dB |
| Pilot cancellation | 60 dB |
| Componentry | 1 FET, 54 transistors, 6 ICs, 47 diodes |
| Dimensions | 48.3 x 16 x 37.1 cm |
| Weight | 12 kg |
Design
The TX-2500MKII has a 1978-era visual redesign and improved internal specs, mostly in the preamp and tuner sections. The tuner uses a 3-gang varicap, two IF amplifier stages, 4-element ceramic filters and an Onkyo-made low-pass filter. The "Accutouch" tuning knob temporarily disables the locking circuits for fast manual tuning. When released, it re-engages the servo-locking, fine-tunes the station and lights the TUNED indicator on its own. The receiver also has one-step on/off muting and a beefy transformer for strong power delivery.
Context
The TX-2500MKII was the second of four receivers in Onkyo’s 1978-1980 range, sitting alongside models like the TX-1500MKII. Onkyo marketed it as a technically advanced receiver with superior tuner performance and increased output, aimed at audiophiles who wanted precision and power in one chassis.
Market
The TX-2500MKII listed originally at $450. Recent sales have run around $200, and some buyers call that a steal. It is considered somewhat rare and is regarded as a desirable, collectible receiver from the late 1970s and early 1980s. Service and owner’s manuals are available. Replacement parts like tuner meters and dial lamps can be hard to find.
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Related Models
- Onkyo TX-1500MKII (1975)
- Onkyo TX-666
- Onkyo TX-4500II (1975)
- Onkyo INTEGRA-A-815 (1978)
- Onkyo TX-2500II (1975)
- Marantz 2226 (1974-1976)
- Marantz 2226B (1979-1980)
- Marantz 2235 (1974-1977)
- Marantz 2238B (1978-1980)
- Marantz 2250B (1978-1980)