There are three blue lights on the front of the Univox DLS-50. They should come on in this order—right, left, center.
The right lights whenever the Univox DLS-50 is connected to a source of power. Normally this light is on all the time. If it is not on your system will not work at all.
The light on the left (labeled “IN” lights when there is an adequate input signal coming from the sound source. Note, it will momentarily go out if the signal drops—such as a pause when a person is speaking or the short intermission between songs playing, for example. This is normal.
The light in the center comes on only when there is an adequate signal going into the loop (room loop or loop-pad). Note, if the power control is set at “0” this light will never come on. You must have the control set at “1” or higher.
The way you adjust the loop power correctly is to turn the thumb wheel in the center until the blue light to the left of the thumb wheel comes on. (I usually initially set it about half way to somewhere around 4 or 5.) Then see how the volume is through your t-coils and adjust the thumb wheel accordingly.
Note: if you leave the power set too high, the Univox will get hot. When the power level is adjusted properly, the top of the Univox should just feel somewhat warm to the touch.
The Univox DLS-50 also has a separate microphone gain control on the back. This gain control only works with the microphone jack on the right. Use it to set the best microphone volume when you are using a microphone plugged into this right-most jack. The gain control is to the left of this jack. If in doubt, set it about half way (so the slot is at 11 o’clock as shown), then slowly turn it counterclockwise until the blue light begins to flicker. At this point you have the correct microphone gain. This light should flicker in unison with the louder parts of music or speech. Note: when not using a microphone connected to this jack, turn the gain control all the way counterclockwise.
If you have the older Univox 2A, here’s how to adjust it correctly.
The green light to the left of it comes on when there is an adequate signal going into the loop (room loop or loop-pad).
The way you adjust the loop power correctly is to turn the power control knob on the left clockwise until the green light comes on. (I usually initially set it about half way to somewhere around 3), then slowly turn it counterclockwise until the green light begins to flicker. At this point you have the correct power going into your loop. The green light should flicker in unison with the louder parts of music or speech.
If you leave the power set too high, the Univox will get too hot. When the power level is adjusted properly, the top of the Univox should feel cool to warm to the touch depending on the size of your loop.