A friend who runs a vintage instrument shop, the clientele is of which is such that the shop scarcely needs me to flog it on this blog, acquired a mellotron recently. I learned a couple of things about the mellotron today.
First off, my long-held supposition that mellotrons used tape loops was entirely wrong. While the concept of a tape loop looks good in one's head, it is apparently impracticable in reality. Pressing a key on the mellotron, rather, engages a tape strip, which runs over the playback head that pressing the key engages, and the physical tape in the strip actually drops into a narrow box, and at the end of the eight-second duration of the tape strip is SUPPOSED to be automatically rewound for replay. As it turns out, one of the issues with a mellotron (and another thing I learned was that mellotrons have LOTS OF ISSUES) is when the tape strip drops down into the box and just stays there, and then you get a key that's just silent when you press it. This tended to compromise my attempted by-ear recreation of the opening of "In The Court Of The Crimson King." I found this discouraging.
Note the A-B-C switch on the upper right of the metal panel of the mellotron. That changes the setting of the recording. The recorded instruments on the tape cartridge currently installed in this mellotron are flute and a string section. The third recording is of a choir, called "voice." However, if you toggle the switch to put it between A and B, say, you can get a kind of "mix" of voice and strings; toggle between B and C and you get a mix of strings and flute. This is not unlike what guitarists discovered of the ostensibly three-position pickup toggle switch on Fender Stratocasters. The switch selected neck, middle or bridge pickup, and that was it. But if you poised the switch between positions one and two, they got a mix of the neck and middle pickup. Between positions two and three, a mix of middle and bridge pickups. Eventually Fender got the message and made the switch a five-position geegaw. But the action on the '75 Strat I handled today was so sweet I'd be willing to live with the three-position switch.
But we're talking mellotron. Which is, in practice, a wonky, difficult instrument. "It's ridiculous," noted thefriend I came to the shop with, "but it's a retro thing, so everybody with Stupid Rockstar Money wants one." He, a professional musician of some repute, was able to conjure a few better-than-passable runs out of the thing. This irritated me a bit, as did his competent runs on a ukelele. "Oy," I whiged in a stage whisper to S., the shop's overseer. "Even HE plays guitar better than me. He's not even supposed to play guitar. He's a front man."
"What are you in your band?" S. asked.
"The front man."
"So what are you complaining for?"
Apparently when S. bought the mellotron he did not acquire an ornamental side panel that features a painting of a unicorn on it. This item is still in negotiation. I will provide an update if called for. In the meantime, here is a PDF of the Owner's Manual for the 400N.