THE PRECISION NBC215

Many years ago (say late 70's / early 80's), at Martin Audio's Stanhope Street London factory, I saw lots of x-overs built for Martin by an outside contractor on 18mm birch plywood.

I noticed the superb build quality.

The x-overs were reliable enough for touring rigs, with everything stuck down / fastened to the plywood correctly.

Some of those inductors were huge & heavy too.

MarjanM wrote: odc04r wrote: They may both work, but I know what is more professional. And I've ordered a minimum quantity of 5 boards quite a few times recently for some designs. 500 MOQ is not true. I dont need to go to china for this, i have a local pcb maker that can make pcb's up to 14 layers. Quite reasonable with pricing too.

Yet you use wooden PCBs in your systems up to 3500W? Why would you do that?

L8 ECU wrote: Many years ago (say late 70's / early 80's), at Martin Audio's Stanhope Street London factory, I saw lots of x-overs built for Martin by an outside contractor on 18mm birch plywood. I noticed the superb build quality. The x-overs were reliable enough for touring rigs, with everything stuck down / fastened to the plywood correctly. Some of those inductors were huge & heavy too.

i still have one of the original Martin xovers in my workshop somewhere, will try and dig it out

That's hardly a typical crossover though, is it? (Why don't you just bolt the coils to the cabinet?)

And I would be very surprised if you mounted power resistors directly to the wood without any heat sinking or external support, as in the crossover in question.