Convert mini Pre-amp from AC to DC power - diyAudio
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Old 24th November 2012, 02:59 AM   #1
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Default Convert mini Pre-amp from AC to DC power

hey guys I have this mini Pre-amp I want to use in my portable speaker system but it will not work with DC power source.

Anyway to modify it to work on DC?

It said only AC on the description but I figured I would try it.

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Thanks!!
Mike
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Old 24th November 2012, 06:42 AM   #2
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The preamp itself runs from regulated +12 & -12 VDC.
The extent of power supply mods depends on the main energy source.
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Old 24th November 2012, 09:57 AM   #3
AndrewT is offline AndrewT  Scotland
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Remove or short the To92 regulators.

A pair of 12V batteries.

6 series connected lead acid, or 10 series connected Nicad, or 10 series connected Nimh, etc.
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Last edited by AndrewT; 24th November 2012 at 10:00 AM.
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Old 24th November 2012, 04:42 PM   #4
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Quote:
Originally Posted by sofaspud View Post
The preamp itself runs from regulated +12 & -12 VDC.
The extent of power supply mods depends on the main energy source.

The manufacture says AC and I hooked up DC and it would not work.
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Old 24th November 2012, 04:44 PM   #5
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Quote:
Originally Posted by AndrewT View Post
Remove or short the To92 regulators.

A pair of 12V batteries.

6 series connected lead acid, or 10 series connected Nicad, or 10 series connected Nimh, etc.

OK I guess this makes sense, so I don't need the regulators?

I have a +12 0 -12 DC power source.
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Old 24th November 2012, 04:49 PM   #6
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when you say short them or remove them how would I short them? they have 3 terminals. which of the 3 would I short?

MP
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Old 24th November 2012, 07:03 PM   #7
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Remove the 2 regulators and solder the new power supply wires where the regulator Output and Ground pins were. Refer to the datasheets; the 2 regs have different pinouts.
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Old 24th November 2012, 07:32 PM   #8
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Originally Posted by sofaspud View Post
Remove the 2 regulators and solder the new power supply wires where the regulator Output and Ground pins were. Refer to the datasheets; the 2 regs have different pinouts.

K, thanks!! Just to make sure I get it, I remove both regulators completely then feed my power source to the output pin of where the regulator was? put +12 and ground on one and -12 and ground on the output pin of the other regulator?

So the power comes in and goes to the regulator then goes to the op-amp? by doing the above I am bypassing the regulator and sending power directly to the op-amp?

Mike
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Old 24th November 2012, 07:37 PM   #9
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yes and yes
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Old 24th November 2012, 11:06 PM   #10
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Quote:
Originally Posted by ExtraCredit1 View Post
The manufacture says AC and I hooked up DC and it would not work.
It could be the AC adaptor is providing positive and negative voltages and simply plugging in a single phase DC supply wont work.
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