They usually have an input impedance of 50KΩ to 100KΩ depending on model (Tascam Porta).
An obvious good choice may be using a Sony F-96 hi Z.
Also other omnidirectional mics with hi Ζ option such as MD21 H L.
If we would like to connect a 200Ω balanced microphone, the obvious choice is a low to high impedance coverter step up input trasformer. Some come inside an XLR to 1/4in adaptor.
But for even better (top of the world) sound with no hiss...
A small digression...
Hiss does not come from tape or cassette, it comes from the preamplifier. It is manifestation of electrons moving randomly.
A cassette recording has a dynamic range of say 40dB.
A pop music song usually may have a dynamic range of only 20dB. This can be easily verified by looking at VU meters when a favorite song is being payed.
To have low hiss it makes sense to record in a quiet place, with a quality microphone, and a top quality input transformer and pre preamplifier or preamplifier, singing or playing softly to avoid nasty dynamic range peaks in the waveform and then get this signal above the noise floor of tape. Singing or playing softly create a loud end result, assisting any then digital medium not to nastily overload (see the Sound on Sound reference on how to make a loud mix on previous euroelectron post).
To have low hiss it makes sense to record in a quiet place, with a quality microphone, and a top quality input transformer and pre preamplifier or preamplifier, singing or playing softly to avoid nasty dynamic range peaks in the waveform and then get this signal above the noise floor of tape. Singing or playing softly create a loud end result, assisting any then digital medium not to nastily overload (see the Sound on Sound reference on how to make a loud mix on previous euroelectron post).
So to get to world class quality we need a state of the art booster preamp between the output of the input transformer and the Hi Z input of the 4 track caste recorder etc.
Pleiades pre preamplifiers, electron tube V series, or JFET K117 do the job in an amazing way. (For some applications just a Pleiades step up trasformer will be enough).
They are the simplest possible signal path on the planet like what is inside a Neumann U47. In fact the schematics are very similar.
Pleiades schematics can be found on other euroelectro posts.
The Pleiades V4 for example uses just an EF183 electron tube, triode connected, 2 coupling capacitors, 1 few Megohm resistor from anode to grid (to accelerate electrons) and that is all. It operates with just a 3.6 battery for heaters and anode too. The low noise and amazing dynamic sound is a joy to hear.
If you wish you can wind your own input transformers. It is very simple if using a state of the art Nanocrystalinne extremely high inductance index Magnetec Nanoperm toroidal core.
By adjusting the number of primary turns, bass cut is adjusted so the proximity effect is compensated and can be fine tuned to using for example a vintage unidirectional Shure Unidyne III (SM57), the model of microphone used by Brian Wilson singing on Pet Sounds.
One may also make the Pleiades K177 pre preamp using just a K117 JFET and a handful of components.
Pleiades schematics are open source and anyone can do anything they wish including improving them.
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