Thanks. Seem to not have any 4" mid pics... grr.

There might be an issue with the jumper config on the Zapco BTL unit. On many BMW's in the past, installers have run the OEM balanced preout signals straight into the amp without using a BTL. The BTL is a bare-wire-to-Symbilink-balanced adapter, and we used it in this car rather than chop a Symbilink cable in half.

The BTL jumper configuration we settled on was electrically the same thing, though - bypassing the caps and resistors on the board and making it a straight line pass-through. With caps in and no resistors the highs sounded glare-y and harsh. We did not hear a difference between no caps and no caps-or-resistors.

But... we have an intermittent problem with the HU going silent after a key cycle and not sending audio out either the F (going to the Zapco) or the rear (still going to the OEM amp!) until after the Zapco is disconnected. The moment the Zapco is disconnected the audio comes back out of the HU!

So I'm thinking that we needed to leave at least the resistor portion in there. We are going to test my theory this morning. More updates as they appear on this and other stations.

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