Description

The Transistor TAPEHEAD module allows for the signals recorded to magnetic tape to be heard by amplifying the tiny induced currents generated in a tapehead.

Tape replay needs a special amplifier for a few reasons. First to boost the signal up from approx 1mV up to Eurorack levels you need a whole lot of gain. 

Secondly, due to various non linearities when signals on magnetic tape are read by a tape head a flare EQ cannot be used…. to add to complication tape speed, the type tape also all have their out added effect. 

So without getting into the physics too much a filter of sorts is used to compensate and give a flatter EQ!

The modules preamplifier stage is based on a discrete transistor circuit example given by Nortronics (a tape head manufacturer) in their datasheet circuit examples. It has the extra functionality that you can adjust the HF shelf EQ for playback at different speeds or tape type. I included a 3 position switch for either 4.5 / 9 cm/s standard tape speeds or the variable control. 

Another consideration with tape replay is that as the tape speed increases the output volume also increases, vice versa at low speed the output can become very quiet.

So to make up for this the gain structure covers a wide range with a H – M – L high medium low 3 position switch and a Gain knob that can also turn the output volume down to 0.

This module will form part of DIY 3U TAPEDECK for Eurorack.

The idea is there will also be a motor driver module, passive unpowered Tape deck mechanism panel and a Transistor Tape recorder module. The 4 modules together will make a DIY tape machine!