Hi all
I am running a set-up whereby the soundcard of my PC runs into a power amp, which in turn runs a pair of speakers, and feeds a subwoofer via the Pre-Out
My goal was to have a crossover unit, so that the signal is cleanly split by frequency between the sub and the speakers . The sub already has a lo-pass so this wasn't an issue, but the speakers are still receiving a full range signal, so I believe the woofers are overlapping with the subwoofer to some extent at the low end
I am a total newbie at this sort of thing but decided to jump in anyway and buy some gear to create the crossover
I have the following components to create the crossover (crossover PCB, power supply PCB, and a toroidal transformer which I was advised to get by the seller):
Line-level Active 2-way Crossover Filter NE5532 BUILT AND TESTED | eBay
High Quality Dual Symmetrical Power Supply for Audio Amp UK Designed & Produced | eBay
MCFM50/12 - MULTICOMP - MINI-TOROIDAL, 5VA 2X 12V | CPC
I cannot for the life of me figure out what kind of connectors are needed to join the two boards. They appear to have 3 sockets, marked -V, GND/0V, and +V respectively. Have googled myself silly to no avail - would anyone be able to point me in the right direction?
I also would appreciate some help on how wiring the transformer to the power board and the mains - from what I gather, if I do this wrong it might start melting and burning things. I do not want to melt or burn anything
I am running a set-up whereby the soundcard of my PC runs into a power amp, which in turn runs a pair of speakers, and feeds a subwoofer via the Pre-Out
My goal was to have a crossover unit, so that the signal is cleanly split by frequency between the sub and the speakers . The sub already has a lo-pass so this wasn't an issue, but the speakers are still receiving a full range signal, so I believe the woofers are overlapping with the subwoofer to some extent at the low end
I am a total newbie at this sort of thing but decided to jump in anyway and buy some gear to create the crossover
I have the following components to create the crossover (crossover PCB, power supply PCB, and a toroidal transformer which I was advised to get by the seller):
Line-level Active 2-way Crossover Filter NE5532 BUILT AND TESTED | eBay
High Quality Dual Symmetrical Power Supply for Audio Amp UK Designed & Produced | eBay
MCFM50/12 - MULTICOMP - MINI-TOROIDAL, 5VA 2X 12V | CPC
I cannot for the life of me figure out what kind of connectors are needed to join the two boards. They appear to have 3 sockets, marked -V, GND/0V, and +V respectively. Have googled myself silly to no avail - would anyone be able to point me in the right direction?
I also would appreciate some help on how wiring the transformer to the power board and the mains - from what I gather, if I do this wrong it might start melting and burning things. I do not want to melt or burn anything
If you have an ohmeter (and you do need one), you can find where on the crossover board you need to hook the +V power supply lead, by looking for continuity (less than an ohm) to pin 8 of any 5532 IC. There will be pads somewhere on the board, probably near an edge, where the power supply wires are supposed to be connected. Pin 4 needs to hook to the -V. But don't hook up the crossover board to the power supply until you've hooked the toroid to the power supply board, and verified with a voltmeter that the power supply works right.
Assuming that the secondary of the toroid has two windings (4 wires), you need to connect the correct end of each winding to the correct end of the other winding, and that will be tied to Gnd on the power supply board. The remaining two ends of those two windings will go to the AC inputs of the power supply board (swapping them won't matter since it's AC). I'd need to see a spec sheet (pinout) of the toroid to be able to tell you which two wires to join for the ground node.
Once you get + and - 12 volts clean DC out of the power supply, you can then hook it up to the crossover board.
When mounting it all in a chassis, tie the ground connection at the crossover board to the chassis in only one location. Use connectors that isolate the ground connection from the chassis. Tie those Gnd connections to the Gnd of the crossover board where the power supply connects. Keep the wires leaving the toroid away from the crossover board and any audio signal wires. They radiate an electromagnetic field that can cause hum. Twisting the wires (pairs) leaving the toroid will reduce the amount of field they emit.
Assuming that the secondary of the toroid has two windings (4 wires), you need to connect the correct end of each winding to the correct end of the other winding, and that will be tied to Gnd on the power supply board. The remaining two ends of those two windings will go to the AC inputs of the power supply board (swapping them won't matter since it's AC). I'd need to see a spec sheet (pinout) of the toroid to be able to tell you which two wires to join for the ground node.
Once you get + and - 12 volts clean DC out of the power supply, you can then hook it up to the crossover board.
When mounting it all in a chassis, tie the ground connection at the crossover board to the chassis in only one location. Use connectors that isolate the ground connection from the chassis. Tie those Gnd connections to the Gnd of the crossover board where the power supply connects. Keep the wires leaving the toroid away from the crossover board and any audio signal wires. They radiate an electromagnetic field that can cause hum. Twisting the wires (pairs) leaving the toroid will reduce the amount of field they emit.
Hi thanks for the explanation
I have emailed the seller for the wiring specification on the transformer, so once I have I'll post it.
It does have the four-wire end like you describe. From my understanding, I would wire the three-wire end into a standard mains plug, and the four-wire end would then go into the input of the power supply board as per your description - is this correct?
I was also unclear on some of the other things you said.
Firstly neither board came with any connection cables, so I need to know what cables to buy to hook the two boards together.
Here are some pictures of the terminals:
Crossover input:
Power supply input:
Power supply output:
For the transformer, presumably I can just put the bare wire ends into the sockets?
Secondly you mentioned the 5532, which is also written on the board ("use NE5532 or equivalent"). How would I go about connecting this device? Would it be like the following:
Power supply output > 5532 > crossover input, with pin 4 to the -V and pin 8 to the +V? And again, what cables would be needed for this?
I'm unsure what you mean by "you can find where on the crossover board you need to hook the +V power supply lead, by looking for continuity (less than an ohm) to pin 8 of any 5532 IC" - surely the power supply connection will just go to the input terminal of the crossover pictured above?
Finally, this part:
mainly went over my head. Could you possibly put this in simpler terms or give a step-by-step of what to do and where to acquire appropriate connectors and chassis?
In hindsight I probably should have just bought a fully assembled crossover unit, heh. My ignoramus assumption was that there'd be some kind of power lead just to directly connect the crossover board to the mains, like plugging in a TV or something. Oh dear...
I have emailed the seller for the wiring specification on the transformer, so once I have I'll post it.
It does have the four-wire end like you describe. From my understanding, I would wire the three-wire end into a standard mains plug, and the four-wire end would then go into the input of the power supply board as per your description - is this correct?
I was also unclear on some of the other things you said.
Firstly neither board came with any connection cables, so I need to know what cables to buy to hook the two boards together.
Here are some pictures of the terminals:
Crossover input:
An externally hosted image should be here but it was not working when we last tested it.
Power supply input:
An externally hosted image should be here but it was not working when we last tested it.
Power supply output:
An externally hosted image should be here but it was not working when we last tested it.
For the transformer, presumably I can just put the bare wire ends into the sockets?
Secondly you mentioned the 5532, which is also written on the board ("use NE5532 or equivalent"). How would I go about connecting this device? Would it be like the following:
Power supply output > 5532 > crossover input, with pin 4 to the -V and pin 8 to the +V? And again, what cables would be needed for this?
I'm unsure what you mean by "you can find where on the crossover board you need to hook the +V power supply lead, by looking for continuity (less than an ohm) to pin 8 of any 5532 IC" - surely the power supply connection will just go to the input terminal of the crossover pictured above?
Finally, this part:
mainly went over my head. Could you possibly put this in simpler terms or give a step-by-step of what to do and where to acquire appropriate connectors and chassis?
In hindsight I probably should have just bought a fully assembled crossover unit, heh. My ignoramus assumption was that there'd be some kind of power lead just to directly connect the crossover board to the mains, like plugging in a TV or something. Oh dear...
It's really very easy.
Just post a photo of the label on the transformer so we can tell you which wires to put in what position on the PSU board.
Then on the output of the PSU board connect as follows:
+V to +V
0V to GND
-V to -V
The wire can be anything, it's not power wiring. 7/0.2 available from Maplin or 24AWG will be fine.
I am a little confused by this though. The transformer should have two wires for its input. The four wires are its outputs.
That is exactly right. Now that you have posted photos of the connector we can see that it's clearly marked and no further examination/testing is required.
The final wire that needs sorting is earth back to the mains. This should be a thicker wire than all the others and goes from the earth input of your box mains input socket to the 0V/GND connection on the PSU board. There should be another wire of same thickness from the box mains input socket earth terminal to the (metal) box, held in place by an M4 bolt with shakeproof/star washer between the crimped ring terminal you put on the wire and the panel, and another shakeproof/star washer under the nut. This screw must not be used for anything else - fixing etc.
Just post a photo of the label on the transformer so we can tell you which wires to put in what position on the PSU board.
Then on the output of the PSU board connect as follows:
+V to +V
0V to GND
-V to -V
The wire can be anything, it's not power wiring. 7/0.2 available from Maplin or 24AWG will be fine.
I am a little confused by this though. The transformer should have two wires for its input. The four wires are its outputs.
That is exactly right. Now that you have posted photos of the connector we can see that it's clearly marked and no further examination/testing is required.
The final wire that needs sorting is earth back to the mains. This should be a thicker wire than all the others and goes from the earth input of your box mains input socket to the 0V/GND connection on the PSU board. There should be another wire of same thickness from the box mains input socket earth terminal to the (metal) box, held in place by an M4 bolt with shakeproof/star washer between the crimped ring terminal you put on the wire and the panel, and another shakeproof/star washer under the nut. This screw must not be used for anything else - fixing etc.
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