What's the correct way to connect PC->Amplifier->Speakers?

[zx2012]

The PC has two 3.5mm sockets. One inside that is green(G) and one outside that is marked with a headphones(H) icon.

 

I have the following:

 

1. Dell Optiplex PC

2. A 3.5mm cable that has one black jack and one red jack.

3. An amplifier. Has 4 connections, 2 for the right and 2 for the left. Right and left have one red and one black.

4. Two speaker cables with a jack on one end that splits into two bare wires at the other. Each cable has two wires one of which is marked with a black line. That gives four connections at the amplifier end.

5. The wall socket is marked PC speaker and marked with an L and an R.

6. Video splitter

7. Interactive whiteboard power supply brick.

 

Are the PC sockets G and H the same?

 

If I plug cable(2) direct from the PC(H) into sockets(5) The sound works fine from the speakers above interactive whiteboard. It's just not being loud enough for the classroom.

 

If I plug cable(2) direct to the amplifier. Which input should I use, the choices are DVD, Tuner, CD, AUX1 or AUX2?

 

How do I connect the 2 cables(4) to the wall? I've tried every combination I can think of! Most of the time I either get a high pitched sound, crackle or nothing. In one case get I had one speaker working on the left put but only the right cable was plugged in to the wall socket(5)!

 

Does all equipment(PC, amplifier, PC monitor, video splitter and interactive whiteboard power supply brick) need to come from one power source? There are two sockets on the wall and I have one 4 way extension lead.

 

Is there a diagram somewhere that shows how it should work?

[thedarxide]

Cable (2) goes to the amp. We choose AUX because the staff know that a computer isn't a CD, DVD etc.

 

Speaker wires - the side with the black line is the negative, put that in the black terminal and the other side in the paired red terminal.

 

You can use the 4 way extension lead but the combined amperage of all the devices on must not exceed 13 amps.

 

edit - I'm not sure what the wall socket is for?

Edited September 5, 2009 by thedarxide

[Andrew_C]

When you say amplifier, do you mean something that looks like it could be used as a home HiFi, or a speaker with an amplifier built in, and a pair of satellite speakers. The sort of thing you might use on a desk?

 

If the former, the answer above should get you going. If you have a Creative sub - satellite set up they are just not up to the job. They sound fine in an empty room when they are demonstrated, and when tested after an install, but just don't cut it in a room of 30 kids.

 

There are further problems if you try to add a VCR to the mix!

[zx2012]

The Amplifier is a TANGENT AMP100(might be AMP50)

 

Does it matter what electrical sockets all the equipment comes from?

 

How do work out if I will go over 13amps?

 

I have one classroom with:

1 PC

2 Monitor

3 LAN Hub

4 Wi-Fi LAN access point (broadcasts to 2nd half of school)

5 Wi-Fi LAN access point (bridge to main building)

6 VGA Video splitter

7 Scanner (on USB from PC)

8 Amplifier plus connected speakers

10 Interactive whiteboard power supply brick.

 

The cabling for this lot is, erm, a bit chaotic to say the least! Any tips to sort this out would be very welcome?

 

I can't put the cover on the PC as the whiteboard's serial cable is also connected to the power supply brick about 0.75cm from the RS232 socket! (I have now bought a RS232 extension lead so hopefully this will be fixed.)

 

There used to be an ancient laser printer but I've taken it out of the room now.

[laserblazer]

You say you have two 13A sockets? If so, split that lot between the two and you should be ok, mind you, our HSO would have a fit if she saw it I don't let her in my office ) Unfortunately, the amp. details doesn't show the rear panel connections but I assume the there are RCA (phono sockets) red or black and white. If the audio is not loud enough it might be because the volume is too low on the PC.

 

Cables are untidy and do tie themselves in knots over time. Where possible, I use the spiral cable tidies. I got a job lot from Poundland. It would help if teachers left their desks where they were when the whiteboards were installed but they insist that they have to be just beyond the stretch of the cables and when I have it sorted they move the desk. This seems to be NQTs. I think they are taught that regularly moving the desks around keeps the kids on task!

 

Providing the speakers are matched to the amp, I'd say 40W RMS is enough for the average classroom.

[Andrew_C]

That lot would all happily run from one 13A socket and a 4/6 way extension. Some places ban these, and our H&S consultants deprecate "the indiscriminate use" of mains splitters. I agree with the latter, but this would not be 'indiscriminate'; all the devices listed are low power.

 

To work out the load in amps, divide the wattage (found on the equipment labels) by 230. Add all the amperages together.

 

In many ways I would prefer to keep 4ways well below 13A as some are not terribly well made. I am inclined to mark them "No Heaters" and put 5A fuses in them.

[RinSewand]

As for connecting to the speakers - if you plug cable (2) into socket (5) and get sound, it's unlikely that you'll be able to connect from the amp to the socket (5). The speakers are probably already powered, you'd need seperate ones which would have 4 terminals on the back for the wires...

 

RwD