604 8hpln

[bowtie427ss]

I believe the 904-8A is the same speaker.

Not quite. No argument intended Ron. But, if we're talking about these drivers in original form, there are as many differences as similarities beginning with one being built on alnico motors and the other ferrites. With the switch to ferrite came the new model number 604-168X

an original 904 uses a coil, former, and cone very similar to if not the same as 421 to acheive it's 150watt power handling at the cost of steeper LF roll-off.

The HPLN 604 uses a "604" cone with minor modifications to the coil and former to increase the power handling to 80 watts while retaining as close as possible the true sonic signature of a 604. The HF section uses a standard aluminum diaphragm. However, the HF section uses a 16 ohm voice coil to increase power handling.

If the OP's HPLN was re-coned faithfully, then no stock Altec network is going to be plug n play without modifications to compensate for the 16ohm HF load. It's not a big issue, but should be considered.

Just my .02.................