The high-frequency extension is shocking for a 2-head deck. A 15kHz tone remains distinct. However, because it is a 2-head deck (you cannot monitor off the tape while recording), you must trust your levels. The separation between left and right channels is excellent—better than contemporary Sonys.
If you find one at a garage sale with a stuck reel, don't walk away. Pay $20, fix the idler tire, clean the switches, and you will have a deck that out-performs anything new under $500. The CS-F21 is proof that Akai’s "second tier" was still a class above most of the competition. Have an AKAI CS-F21 story or a repair tip? Share it in the comments below. Happy taping. akai cs-f21
This is the sweet spot. The bias accuracy for chrome tape is near-perfect. Piano recordings have weight; cymbals don't turn into white noise. The direct-drive motor becomes apparent in the silence —there is almost no motor rumble (mechanical noise transferred to the tape). The high-frequency extension is shocking for a 2-head deck