Incredibly durable and dynamic (1979 TDK OD C90).

Even after over 45 years, steadfast quality shines through the pure ferric oxide 1979 TDK OD C90. Not only does the formulation sound wonderful, but a properly stored specimen will easily endure being re-recorded multiple times when proper biased. The TDK OD can take on a lot of modulation for a Type I of the era without annoying distortion and saturation. Mid and high range is surprisingly clear and not muddy - - Read: Not muddy!! Remember, this is a all iron oxide-based cassette tape, but it sounds like a Type II without the extra high-end scratchiness. Bass handling is overwhelmingly excellent. The noise level is elevated compared to more modern offerings, but it can be mitigated by the fact that the tape can be driven harder. I did not use Dolby. The shell is similar to TDK SA of the era. I did add a wee bit of silicone lubrication to the idler roller axes to remove the odd squeal of age. In my opinion, the TDK OD was probably best Type I of the era as all my other era Type I's did not age well. Even my once prized Maxell UDXL I's are potholed with drop out - equally stored with my TDKs. If you can find a TDK OD in very good condition, grab it and enjoy. They are uncommon.