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Old 4th March 2012, 07:27 PM   #11
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Hi:

I wasn't able to post because my ISP was having problems.

Ok, since the speaker protection board seems to be a good thing to use, could you please tell me how to power it, in the specifications posted by the seller he says that this requires 12-16V to operate, and that an additional power supply is recommended. I ordered a Antek AS3428, 28V 300VA that has dual 28V outputs and dual 15V outputs. Would this do the job?.
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Old 4th March 2012, 07:29 PM   #12
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Andrew, I have not received the boards yet, as soon as I receive them I will post pictures of them. I saw a post somewhere here and you mention a couple of issues with these boards and how to correct them. I may need your help later on...
Thank you.
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Old 5th March 2012, 05:25 PM   #13
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Quote:
Originally Posted by Aguilabrava View Post
he says that this requires 12-16V to operate, and that an additional power supply is recommended. I ordered a Antek AS3428, 28V 300VA that has dual 28V outputs and dual 15V outputs. Would this do the job?.
Since he says that it need 12-16 VAC one of the 15 V outputs will do.
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Old 5th March 2012, 06:51 PM   #14
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Quote:
Originally Posted by Minion View Post
And that power supply isn"t regulated , it is just a regular unregulated PSU ......
Uh, most amplifier PSUs are non-regulated. The chip amp IC has enough ripple rejection to not require any regulation like a line level circuit.

-Charlie
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Old 6th March 2012, 03:19 AM   #15
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Thank you, pacificblue.

I have one more question, there is an input selector board at the auction site, it has 4 inputs, 1 output, and the seller says that it requires anywhere from 11 to 22 Volts of AC. This may sound like a stupid question, but the truth is I don't know much about this:

Can I use the additional 15V output from the toroidal to power up this board too?.
The seller also mentions that this board has a "regulator output of 12V DC 1A", what is that?.

Following your advice, I just ordered the speaker protection board.

I have attached a picture of the input selector board.

Thank you very much once again.
Attached Images
File Type: jpg input_selector_board.jpg (123.7 KB, 1457 views)
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Old 6th March 2012, 09:40 AM   #16
AndrewT is offline AndrewT  Scotland
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post15 pic.
I can see 4 relays with 4 transistors and 4 diodes.

It appears that the inputs are relay switched using transistors as the trigger.
That an LED lights to show which is selected.

I can't see what is attached to the heatsink, but I will guess it is a 12Vdc IC regulator to suit 12V relays.

Yes you can use a single 15Vac supply. It is between 11Vac and 22Vac.
The 11Vac lower limit is a clue that confirms the 12Vdc regulator.

Check the trigger circuit and/or install information.

The transistors will need a low current low voltage trigger signal. This can be provided by a rotary switch, or other. But you must follow the instruction on voltage and current (source impedance) to prevent damaging the transistors.
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Old 6th March 2012, 01:31 PM   #17
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Default Input board pictures.

Andrew:

I am posting 2 more pictures plus the diagram for this input board.

Here, the specifications as posted by the seller:

Audio input selector module board, with 12V DC voltage regulator.
This item has been assembled, and electrical test passed.

4 Dual channel input, 1 dual channel output.
Led indicator for each relay channel.
Power Supply: 11 to 22V AC.
or 15 to 32V DC.
Regulator output: 12V DC / 1 Amp.
High quantity terminal block, easy connection wire.
FR-4 Fiber glass PCB ( Double Layer ).
Japan TAKAMISAWA signal relays.

Rotary switch wire length 300 mm (11.8 inch).PCB thickness: 1.6mm (0.063 inch).
Size: 100mm(L) x 50mm(W) x 38mm(H),
(3.94 x 1.97 x 1.5 inch).
Attached Images
File Type: png RLY-3-SCH.png (127.9 KB, 1417 views)
File Type: jpg input_board_1.jpg (70.0 KB, 1379 views)
File Type: jpg input_board_2.jpg (80.4 KB, 1226 views)
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Old 6th March 2012, 01:41 PM   #18
AndrewT is offline AndrewT  Scotland
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The trigger voltage and current are already defined by the switch circuit.
The current is ~ 12Vdc - transistor Vbe / 1k5 or ~7 to 8mA. This needs to be ~10% of the relay coil (+LED bypass) current to ensure the transistors are saturated and remain cool. The relay current is likely to be ~40mA. No problems.
The LEDs may run a bit bright. 12V-1.8Vled / 1k0 ~10mA.
Most LED indicators running at 10mA will be too bright in domestic operation. Easy to solve. Change the resistors from 1k0 to 4k7. If too dim then add a parallel resistor until you achieve desired brightness.
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Old 6th March 2012, 01:59 PM   #19
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Thank you, Andrew.

I can then use this board in my project, I'll use one output of 15V from the transformer to power up the speaker protection board, then the other 15V to power this input selector board, and the only problem I'll be dealing with is the excess of brightness in the LED's which can be corrected replacing them with 4K7, correct?.
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Old 6th March 2012, 02:01 PM   #20
AndrewT is offline AndrewT  Scotland
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Yes.
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