Country of Manufacture:Japan
Speeds: 7 1/2, 15
Max Reel Size("): 3"
Number of heads: 3
Head Composition: Permalloy
Head Configuration: Stereo
Frequency Response:(3db): 30Hz to 27,000 Hz
Wow and Flutter:less than 0.01% WRMS.
Signal-to-Noise Ratio:better than 55 dB
Sound quality rating:7 / 10
Long-term reliability rating: 8 / 10
The 4000D-Pro was the ultimate development of the 4000 series which first saw light in 1969. It was also the rarest and so not much data can be found regarding its original price and release date. However a hint can be found from the similarity of the VU meters and gain controls to those on the 1975 GX-230D’s
The 4000D-PRO was a half-track stereo deck with three heads and two speeds (7½ and 15 ips). Only four other Akai decks had this unusual configuration, the GX-400D-PRO. GX-600D-PRO. GX-630D-PRO and the PRO-1000.
Improvements over its predecessors included a wider diameter capstan speed change sleeve which, in conjunction with a smaller pinch roller helped to reduce wow and flutter. An additional tension arm near the left reel facilitated better tape handling.
All other functions and mechanisms were similar to the earlier decks from the 4000-series but this PRO model did not have a sound on sound switch.