Crossfire xs-4k or....

[mylows10 5,000+ posts]

Most companies use the same build houses. Only a few really come to mind with their own stuff....
Some of sundowns. But I honestly think sundown and DD amps are the same.

IA obviously has different amps than anyone else

Companies that everyone hates on like rockford and kicker have their own build houses and designs, after seeing inside a lot of Brazilian amps I'm starting to think Taramps and Sounddigital share a few of their boards.

As do I b2 has their amps made at zenon and jay designs his own. But like you said a lot of the guys use the same boards and in some cases the same design. Just slight differences