Apart from the TM101 mic preamp, all inputs and outputs of the ToolMod units have electronically balanced inputs and outputs that can handle line levels of more than + 30 dBu. The ToolMod system does not include the fully balanced internal circuitry of the V700 series; however, the modules have a total dynamic range of 120 dB RMS or more which is common quality with high end pro audio gear only. Almost all semiconductors, transistors and operational amplifiers are handpicked for the particular purpose; as generally known, even op amps of the same name differ a lot from manufacturer to manufacturer and from plant to plant. All modules can be combined in any way, Input and output amplifiers of the units are tuned in a way that even longer chains of modules will work without a loss of performance. The output drivers are tolerant against all connected cable types and even long cables of high capacity will not cause high frequency loss or any other kind of disturbance.

The TM101 transformer balanced mic pre with high quality input transformer, brand Haufe, Germany, has been optimized for universal use with different microphones and programm material; it is almost identical to the input amplifiers that is used with the input modules of adt-audio’s large format consoles. The entire input stage of the pre amp is fully balanced. The maximum gain of the microphone input is 70 dB; the separate line input can be controlled independently. Since one of the TRS connectors on the rear panel of the frame is used for the line input, two input signals can be connected permanentely and selected by the LINE switch. A three-color peak-present LED indicator, input pad, phantom power, phase reversal and a sweeped high-pass and low-pass filter belong to the standard equipment. The high-pass filter has a steepness of 24 dB/oct. The TM102, which was not part of our test set is quite similar to the TM101 but instead of an input transformer, the input amplifier is a discrete electronically balanced circuit. Since input impedance of such an input amp can be a lot higher than of a transformer balanced input, resistive and capacitive input impedance of the TM102 can be determined by two additional switches that apply ohmic and capacitive load in parallel to the input.

The TM103 DI pre amp is based on a similar principle as the TM101, but of course it is optimized for high impedance source signals like gutiar pick ups and similar equipment. The input impedance of the TM103 is very high. Another TRS jack on the module's top plate is installed in parallel to one of the TRS jacks on the rear panel and makes possible to install the instrument to both sides of the unit. In addition, the second jack in parallel let's you feed thru the pick up signal to a guitar amp. The input mode switches BAL and GND allow different configurations of the input section in order to have a set of options for hum free connection available - one of the four possble positions will work problem free. Ground lift disconnects the input ground to avoid ground loops while 'Bal' switches the input to balanced mode. With this mode, the input reads the difference between the ring and the tip of the TRS jack, but not the sleeve, which is normally connected to ground.