Regarding Onkyo Receivers
Hi guys,
Maybe I can answer some of the questions regarding Onkyo. I started working for Onkyo in 1975 right out of college with a degree in electrical engineering. Originally when I started there, their product line up was the TX220, TX330, TX440, TX560, TX670, and TS500 and a bunch of speakers that were AR wanna be's. To be blunt, the TX220, TX330, and the TX440 used power modules with limited slew rate and frequency response and were dull and sounded pretty awful. I don't know if you know the history of Onkyo but in Japan, they were known as Osaka Onkyo and started as a speaker manufacturer. They originally came to USA as a joint venture between themselves and Mitsubishi and failed miserably at selling Onkyo speakers. Mitsubishi and Onkyo parted ways after about 6 months after I was hired and Onkyo started concentrating on achieving better sounding receivers and tuners. The first attempt was the Onkyo T-4055 tuner which had an awesome review in Absolute Sound. After the review came out I remember that we never could keep the tuners in stock. When we were ready to start conceiving the new receiver line, we came up with a different look than the last product line as it became known as the TX2500 and TX4500 (We didn't have enough budget to develop a complete line then). It's hard to imagine but this was Onkyo's last ditch effort to survive in the audio world and they put all their marbles into these 2 receivers. Onkyo was definitely ahead of its time because they realized the importance of a good phono preamplifier even when their older separates were made (A-7022 and A-7055). If you compare the transient response of the phono preamps in those units to their peers, it was immediately obvious. In our earlier test, we would inject a pulse followed by a since wave and check the dilation of the pulse into the sine wave and the phono preamps were outstanding! The TX2500 and TX4500 incorporated these design parameters so their phono section sounded remarkably good (This is preHolman's white paper of phono preamp TIM). We also upgraded the analog tuners. The TX2500 had the servo lock tuning and the TX4500 had the quartz lock tuning. The quartz lock tuning worked remarkably well and the tuning accuracy was only limited to the quartz time base in each unit. Keep in mind that this is predigital tuner days for receivers. Then we concentrated on the power amplifiers. The power amplifier section of the receivers rivaled Harman Kardon's receivers by achieving low tilt figures for the low frequency and high slew rate for the upper frequency response without sacrificing hum and noise like HK did. If there's any negative comment regarding their product line was that the tone control/line preamp amp lacked the same type of clarity and transient response. The success of TX2500 and TX4500 catapulted Onkyo into the audio world and then the development of the TX1500 and TX8500 began to create a full line of receivers. A few years later, the Mark II series of the original line was introduced but it was a variation on a theme of the original product line. Another interesting product line that you might be able see on ebay is their original Integra line. If you ever have a chance, check out the P303 preamp and M505 power amp. They both have unique circuitry and cosmetics that might interest the collectors. The P303 is literally a straight line preamp with a MC stage with gain. The front panel is sparse but the sonic characteristic is phenom. The M505 (105 wpc) is a bit underpowered but the transient response is awesome. As years progressed, Onkyo because less interested in the sonics and more in profits and I left the company (I think in 1978) to pursue product development in separates with Nikko to revamp the Beta, Gamma, and Alpha separates. As of now, I still have a TS-500 Quad Receiver, T-4055 tuner, TX4500 MkII, and a broken TX4500. I'm looking for a new glass front panel for the TX4500 because the shipper that sent the TX4500 packed it so poorly that it damaged the glass. I still have sentimental attachments to alot of their product because it brings back great memories of the earlier stages of my career in the audio industry. Someday when I actually can find time, I'd like to restore the TX4500 and redesign the tone control circuitry to match the rest of the receiver.
Wtih warmest regards,
Tom Ishimoto
Northridge Electronics
