mellotron sampler?

Bjorn Kolbrek bjornk at studpors.hit.no
Tue Mar 28 08:26:22 CEST 2000


>whats the minimal amount of circuitry I need to make a device that can 
>convert a normal audio signal to the signal that a record head needs, and 
>converts what a play head reads back to another standard audio signal? Does 
>this involve complicated processing? or are tape heads pretty simple 
>devices?

Tape heads are not very complicated devices (just an electromagnet fed with
the audio signal). To drive it you may need a couple of volts, depending on
tape, bias and such. With higher bias you can put more signal onto the
tape(better S/N), but you loose highs. You could probably drive it with a
op-amp+maybe a emitter follower. You will need to boost the highs when
recording and boost the lows and attenuate the highs at playback. This is
because the playback head ideally gives an output wich rises 6dB/oct.
Attenuating the highs attenuate noise too. 

I don't know what eq you need, but I can try to find it out. Playback will
only need a eq-ed amplifier, as a good op-amp and cirquitry with extremely
low hum (because of the loww end boost) and low noise. be extremely careful
with shielding. 

>2nd, anyone know of where I can buy in bulk things like tape heads with a 
>cassette holding chassis and some voltage controlled motors?
>(I know this is probobally 2 different suppliers)

sorry. But try to find old tape decks, a lot of people may have old
discarded decks. 

>thanks.
>
>PS. I hope you all can put up with this very irrational idea, but I'm a big 
>fan of doing things the hard way, 

Me to. I build a relay controlled synth at
http://www-studpors.hit.no/~bjornk/madsynt/madsynth.htm

Bjorn




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