Thum & Mahr Stereo Audio Distribution Card - Transformer I/O

Thum & Mahr broadcast quality audio distribution card with six audio transformers. Tested and working.

Two inputs and eight outputs (each input ‘feeds’ four outputs). The inputs are floating transformer balanced as are the outputs, two outputs are derived from each transformer (separate windings - four output transformers total). The input transformers are in mumetal screening cans. There is a gain trim for each of the two channels with a range from -6db to +10db. There is also a capticance multiplier (‘ripple eater’ as some call it) at the DC input - with the required +/-16vdc input the op-amps are fed approx. +/-15v. I’ve added a frequency response plot of one channel / one output to the photos section, as can be seen it has very respectable response indeed. (I did plot both channels / all the outputs and they are very well matched!).

This requires (not included) a regulated / lo noise dual rail power supply of +/-16vdc. You will need electronics knowledge to connect this up properly without damaging it, mistakes with the power supply / connecting it up incorrectly could easily cause damage.

Supplied with the mating connector as pictured with XLR inserts for the two inputs and 8 outputs (which I have added to aid testing / will leave attached) plus wires for connection to suitable PSU.

If you need any further information please ask.

Sent tracked via Royal Mail within the UK mainland only.