ProSub 15 xover

[DjMaxi]

Hi all,

First time post.... I am after some help with the wiring on one of my prosub 15's... I took it apart to clean and re-trim.. the question I have is :- on the transformer bit that connects up to the xover/connector plate, which wire is the positive and which is negative??

The only way I can connect it back seems odd, as in the black is going to red, and red going to black... I made a school boy error and didn't note how it was originally wired up. ( on the transformer the very left wire is black and right wire is red)

This is the one 1 disconnected.. transformer shows black on left and red on right

20221011_201450.jpg (233.44 KiB) Viewed 2581 times

On my second ProSub 15 the very left wire on transformer is red then goes to red on connector plate, and right hand wire is black goin to black on connector plate...

This is the untouched sub, transformer shows red on left and back on right

20221011_202028.jpg (2.12 MiB) Viewed 2581 times

Can anyone confirm (with pics if poss) which is the correct way the wires should be.?

Many thanks.
Maxi

[dak]

This is clearly not something that can be reliably resolved by images since the wires exiting the respective transformers (autotransformers?) are differently colored between the different pictures. Now you don't show the rest of the transformers (?). If there are only two wires and nothing else exiting the "transformers" (and frankly, for a subwoofer I'd be surprised if there were anything else), these are not transformers but inductors. In that case, it does not matter at all which way round you connect them.

[DjMaxi]

Hi Dak,

Thank you for your reply.

I have attached a pic of the wiring in the sub that I have not took apart... yes the wiring colours and indeed layout is slightly different to the one I'm currently refurb'ing... there are only 2 wires 'exiting' the inductor.

Better pic of good sub and 'inductor'

20221011_223025.jpg (1.74 MiB) Viewed 2577 times

Could you possibly explain what the function of this inductor is exactly?

Going of what you have said, I will just reconnect them black to red and red to black... as its the only way the male/female bullet connectrs will go... just seems odd to me, seeing that my 'good sub' is wired red to red and black to black.

Again, thank you, i appreciate your help.
Kind regards
Maxi

[dak]

Well, if it's just two wires exiting the inductor, it's an inductor. That is part of a crossover that will block higher frequencies, something you are likely to do with a subwoofer. If we want a device that approaches an impedance of 8 ohms at 75Hz, it will need an inductance of about 8ohms/(2 pi 75 Hz)=17mH. If you want that kind of inductance with a low DC resistance, you'd need quite a bit of copper (thick wire, many turns) without a magnetic core. So this looks like a transformer because it actually is not working far off the 60Hz that a mains transformer is operating, and with a low DC resistance. The core makes this a much more compact part than coils with an "air core".

It would be frowned upon by audiophiles (and indeed the distinction is not entirely snake oil like so much else), but Peavey is more about sound and affordable engineering, and the magnetic losses and non-linearities of the speakers themselves are such that it is pointless to imagine this kind of perfection at their terminals will somehow make it out in recognizable or measurable manner.

Either way, with just two terminals the coloring is utterly irrelevant. I am almost willing to bet that your speakers are "made in U.S.A." since I cannot imagine that the color mismatch would have made it through Chinese quality control (after all, it looks wrong even if it has no chance to be wrong). To let it through requires knowing that it is irrelevant and treating it accordingly. Namely you need competence and confidence, and a certain disregard for optics.

[Dookie]

Could you take a picture of the other side of the Crossover or the input side? Does it have High Pass Outs along with 2 inputs on it or just 2 inputs?

[DjMaxi]

Hi Dookie,

Some pics attached for you of the connections and crossover

Thank you

[Dookie]

Looking at the back there is a 1/4-inch for the input and a speakon input. The output side has a "High Pass Out" that means there is a crossover in there to take the lows out and feed a Mid/High speaker to use with the sub.

I can't see the trace well but if the 50uf and 72uf are combined for 147uf total that would take around 220hz and below out of an 8-ohm speaker plugged into the High Pass Out jack or 400hz and below out of a 4-ohm load. The inductor I can't see the value of but I'm betting it is taking around 220hz and above out of the woofer in the sub. Both would be roughly 6db's per octave depending on speaker impedance depending on frequency. Unless they are using one of those capacitors (the 50uf or 72uf) to work with the inductor for a steeper slope for the woofer that would make sense that the 2 capacitors are connected together. With the inductor, plugging it in either way wouldn't matter unless there is something hidden under the PC board that can't be seen in these photos.

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Doug