DIY - HAES 4 Channel Amp Gain Boost Mod

[epapp]

What is the wattage rating of the 0805s?

Also, how did you get the non-filtered signal to the woofers in the doors?

Ah, the good 'ol 0 ohm resistor trick...AND TL074s!This is like undergrad senior design all over again.

Might those caps you have '?' on be bypass caps? What are their values? It would make sense for the differential setup.

[Mazman]

0805 resistors would normally be 1/8 W.

To get the unfiltered signal to the door speakers I just set the head unit pre-amp outputs to full range rather than sub out. I won't swear that the door speakers are operating at full range but I definitely can hear some mid range and highs out of them. You can 'scope them easily enough if you have an oscilloscope and a test CD that does a sweep tone and find out what the real response is. I might do that at some point.

Those input components to ground had a 'j' indicator on them that I didn't recognize. They might be high pass filter caps but the overall frequency response would be dependent on the source impedance of the pre-amp outputs, which can potentially vary. I could have taken them out and put them on an LCR meter to find out what they are but I decided that it wasn't worth the effort.