Help me read this Peavey schematic

[Randall]

Crossover for a PA cab. Start with the two parallel input jacks, J1 and J2, what is g4 under them, and what is HIBMNI? Next, right after them are J6 and J14, what are they as well as several others scattered around, and what is MMP and FMP? And L2, why is it not drawn? There is no L2 on my board. Very odd to me.

SP2-4XTcrossover.pdf

[nickb]

All these acronyms are likely just a fields in the schematic capture program they used. They could refer to the the symbol name or the PCB footprint or something else like that. The likely purpose of this schematic is to create a PCB so all that needs to be shown is parts that are actually soldered to the PCB. I'd guess L2 plugs in so it is not shown on the schematic.

[Enzo]

MMP and FMP mean Male Molex Pin and Female Molex Pin. In fact that is spelled out in the parts list. They are the pins soldered to the board where you plug a connector onto them.

COnnector J1, J2. Note by the contacts you see t1, TS, t2. t for tip contact. These jacks are special in that they have two tip contacts. As opposed to a tip and ring. That doubles the current handling rating. And the TS means Tip Shunt or Tip Switch if you prefer. Note next to those letters are 1, 2, 3 meaning pins 1,2,3 of the jack. And g4? g for ground and 4 is pin 4 of the jack.


HIDMNI means Switchcraft Hi-D jack, M for mono, NI for non-insulated.

HIDSI means Hi-D jack, stereo, insulated. In the case of the jacks insulated means plastic bushing to insulate it from a metal panel. non-insulated means metal bushing.

The schematic is for the board, L2 is not on the board, it mounts off to the side and plugs onto a couple molex pins. I THINK there is a typo. I THINK the schematic says J6 and J14 for L2. And J11 and J13 for L1. But the layout shows J6,14 for L1. And it shows J5, J10 for L2. One of those must be wrong. I THINK.

[Randall]

Thanks Enzo, I knew you would know, you old fox. It all makes perfect sense now. The thing that perplexed me the most was L2, which thought I didn't have, and could not fathom how in the world the signal is jumping across J6 and J14, which I also thought I didn't have. But of course I do have L2, and it was right in front of me, only it looks like a choke and was invisible to my eyes. Serious "DOH" moment when it jumped out at me.

[Enzo]

Well to be fair, that schematic is drawn in the new style. The old ones were "just schematics" so to speak. Easier to follow then. I have seen a million PV crossovers, and often on larger speakers one or two of the inductors was iron core and off the board. And I have never seen a bad one.