Anybody know anything about the Marantz SD400 cassette deck? 2 speed?


I was just looking at a very interesting vintage (1976) cassette deck that caught my eye.

It is a Marantz SD400 which dates to 1976 and has 2 recording speeds which sounds like it may be a very usefull feature for higher quality recordings.
1 7/8 and 3 3/4.
I have never heard of a 2 speed cassette deck and wondered if the community has or knowledge of this particular animal in general.
128x128uberwaltz
Found a few threads on 2 speed cassette at Tapeheads.
Only the Nak had half speed,the rest by Marantz, Teac, Tascam, BIC. Etc all had the double speed option.
By all accounts it did improve sq a fair bit,not sure what stopped it catching on apart from maybe that car cassette players were all fixed at normal speed.
Guess this is where most home recorded tapes ended up being played, I know mine did...lol.

Still the idea has merit as long as you then play back on same machine. Now you would get one side of vinyl per cassette side of a 90 roughly.

Sounds interesting to me.
The Marantz is different then as its has double speed for higher sq I assume not half speed.
tls49
...  Nakamichi made a 2 speed cassette deck. Can't remember model number and I think it may have been 1/2 of the normal speed.
Yes! The Nak 680 had a half-speed, 15/16 ips option. 
Seems like Nakamichi made  a 2 speed cassette deck. Can't remember model number and I think it may have been 1/2 of the normal speed.
LOL
I have three Nakamichi decks
Just was very curious as to this particular machine and/or the very principle of 2 speed cassette decks as a new one on me.