Mackie 408M Owner's Manual - Page 22

INSERT LINE MIC 1 Mono Channel Strip SLEEVE TIP Unbalanced 1/4" TS Plug SLEEVE TIP TIP (HOT) SLEEVE (SHIELD) Unbalanced TS (tip-sleeve) lines can be accommodated via the TRS jack. Make sure the cord terminates with a TS plug (like a guitar plug), or if it's a TRS plug (like a headphone plug), make sure the ring is tied to the shield, preferably at the source. You can connect an input signal to both the MIC input and the LINE input. The signals are summed together prior to the INPUT LEVEL SET control so they are both affected by it. On the stereo channels 7 & 8, the inputs are summed after the INPUT LEVEL SET control and only the MIC input is affected by it. Channel Inserts The mono channels are equipped with INSERT jacks for connecting external processors into each channel's signal path. The insert point comes after the Mic/Line preamp's INPUT LEVEL SET control and just before the EQ controls. This is a TRS jack specially configured as a combination Send/Return connection point. It is configured with the Tip = Send, Ring = Return, and Sleeve = Ground. This has become somewhat of a standard in the industry, and many cable manufacturers make cables especially for this purpose. With nothing plugged into the INSERT jack, the send signal is directly connected to the return pin via the normalling jack. The INSERT jack can also be used as a direct out from the mic preamps to tape. If you insert a TS (mono) 1/4" plug halfway into the INSERT jack (to the first click), the plug will not activate the jack switch and will not open the insert loop in the circuit (thereby allowing the channel signal to continue on its merry way through the mixer). This allows you to tap the channel signal at that point in the circuit without interrupting normal operation. If you push the 1/4" TS plug in to the second click, you will open the jack switch and create a direct out, which does interrupt the signal in that channel. Do not overload or short-circuit the signal you are tapping from the mixer. Doing so will affect the internal signal. MONO PLUG Channel Insert jack Direct out with no signal interruption. Insert only to first "click." MONO PLUG Channel Insert jack Direct out with signal interruption. Insert all the way in to the second "click." STEREO PLUG Channel Insert jack For use as an effects loop. (TIP = SEND to effect, RING = RETURN from effect.) ring tip sleeve (TRS plug) SEND to processor "tip" This plug connects to one of the mixer's Channel Insert jacks. "ring" RETURN from processor Tip = Send (output to effects device) Ring = Return (input from effects device) Sleeve = Common ground (connect shield to all three sleeves) 22