| schumpe |
Hello,
I want to hook up the following speaker protection board, but I'm somewhat confused on how to.
The labels on the left side in the schematic are (from top to bottom):
VCC
SpIn
A
What I understand is how to hook up the speaker wires (SpIn and Out), the rest is somewhat dubious to me.
I think AC 25-35 V is the connection to power the protection circuit from a transformer, but there's only 1 connector.
+VCC presumably is the positive rail from the amplifier power supply? I have no idea what A is.
I was thinking of using this on a gainclone amp with a transformer that has dual 20V secondaries connected to two rectifier bridges.
The transformer also has 25V (0.5 A or so) secondaries that I want to use to power the protection circuit.
Haven't put anything together, yet, just trying to understand this.
I tried to find information on this particular circuit on this forum and the internet, but wasn't successful.
Thanks in advance for any help.
-schumpe |
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| ACD |
| I can't see your attached pictures :confused: |
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| schumpe |
The pictures are from a website in China. I post the link. Hopefully, you can look at them that way:
http://eshop.diyclub.biz/product_in...products_id=349
The website is very slow, so you have to be patient. At first, I thought posting the pictures individually would be easier.... |
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| ACD |
| there is a ground connection on the scheme ;-) |
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| schumpe |
Well, it looks like I need more help. My electronics knowledge is somewhat limited.
I put together a crude diagram of the situation.
On the left my transformer with dual 20V secondaries for the amp power supply and dual 25V secondaries to power the protection circuit.
On the right the protection board with left and right channel.
So I knew what to connect to Speaker In and Speaker Out.
Thanks for the pointers, ACD! From your post, I assume I have to connect
4a-->8a
5a-->9a
4b-->8b
5b-->9b
That would leave VCC and A to connect. VCC would be the positive supply rail
2-->6a
3-->6b
Could it be that A is the positive supply output that connects to the amplifier? |
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| ACD |
Lets take it another way round ;)
The circuit needs a single supply; 25-35VAC (8A) and ground (9A).
6A is Power Amplifiers Vcc (+rail).
Speaker input is the unnamed connection between 6a and 7A.
I think that 7A is the output current sensor, which may should be connected between one of the output devices and the emitter resistor :confused: |
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| schumpe |
Looks like I'm getting even more confused about this now.
Like I said, my electronics knowledge is not good - I don't even know what a single supply would be. So I'm asking more questions:
Would I connect only one of the 25V secondary leads to 8a on the board? What happens with the corresponding lead from the transformer?
Would the ground connection from the board simply connect to the star ground in my system?
Is the output current sensor, what detects DC current?
And what's the emitter resistor?
Thanks for your help ACD, I thought I could figure this one out, but I kind of overestimated my abilities, hehehehe. Trying to get instructions from the manufacturer but no such luck.
I also looked on the web, if this is a common circuit for the NEC protector chip, but I couldn't really find anything similar.
At least we can agree on +VCC and speaker in and out :D |
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| schumpe |
I received an email from the manufacturer with the following information:
A connect to current amp. transistor/FET emitter resistor 0.22R point.
In connect to amp. output,
Out connect to Loudspeaker
AC connect to power rectifier diode input side
+Vcc connect to power source.
GND connect to Ground
I still don't get what A is, or how to hook up the AC supply. Any thoughts? Is there a more suitable forum for this?
Thanks |
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| ACD |
Here are the connections to the power amp.
Then connect 4a to 8a and 5a to 9a.
Make a connection from the 5a/9a connection to the amplifiers Ground |
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| schumpe |
thanks for the help!
i'll see if i can figure it out now. i'll post the result. |
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| schumpe |
I still don't know where to connect A.
This is a schematic of my amplifier circuit. Any clue where the emitter resistor could be?
Thanks... |
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| ACD |
| You don't need to connect point A, as this are for protecting output transistors. Your amp is an IC amp, which have no output transistors, and as I recall your amp has internal protection. |
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| schumpe |
Thanks so much!
Now that makes perfect sense after all. |
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| salesmonster |
I've just placed an order for the board above from diyclub.biz. Does anyone know the size of this board's footprint? The info isn't listed on the website.
Dave |
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| schumpe |
It's 7 x 11.5 cm and about 3 cm high.
I think you should be able to cut the board in half if you want to separate the channels. It would be about 7 x 6 cm then. |
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| schumpe |
| No problem. It worked quite well for me. Don't expect too much of the quality of the board, though..... |
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