Tapping 12v from a NAP140 clone PCB board

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BIA

Member
2011-01-08 12:14 am
Hi , i have a problem i need help with im planning on assembling a NAP140 clone amp with a 12v DC speaker protection circuit board , can anyone help me with a solution on providing 12 VDC to the speaker protection board form the amplifier board voltage rail . Rather than having a seperate 12 VDC voltage source .



NAP classic clone.jpg

this is the schematic of the Amp
 
Is that safe though ?
i was hoping to tap into one of the exsiting transistors that are on the amp boards and get 12VDC that way
Yes, do it like transistormarkj says.
You can't "tap voltage" from the power amp but from the PSU; in this case from a +40V rail.
Post the PSU schematic just in case there's another possibility but so far this one is good.
 

BIA

Member
2011-01-08 12:14 am
omron relay spec

Coil Current:11.5mACoil Resistance:4.17kohmCoil Type:DC, MonostableCoil Voltage VAC Nom:48VCoil Voltage VDC Nom:48VContact Configuration:DPCOContact Current Max:5AContact Voltage AC Nom:250VContact Voltage DC Nom:30VExternal Depth:25.5mmExternal Height:29mmExternal Width:13mmNom Operating Power:530mWRelay Mounting:Through HoleRelay Type:powerApproval Bodies:CSA / SEMKO / SEV / ULCoil Operating Lower Percent Limit:70%Coil Operating Upper Percent Limit:110%Contact Current AC Max:5AContact Current DC Max:5AContact Voltage AC Max:240VContact Voltage DC Max:30VDC Coil Power:530mWExternal Length / Height:29mmMounting Type:pCBNo. of Poles:2Operating Temperature Max:70°COperating Temperature Min:-40°COperating Time:15msRelease Time:15msSeries:G2RSwitch Current Max:5ASwitching Current Max:5A
 
Not *this* one, you posted data for a 48V DC coil relay, yet your protection circuit runs on 12V
Continue searching fo the proper 12V DC part.
Anyway the current for the 48V one is only 11.5 mA ; the 12VDC one will need around 4X that or 45/50mA (check it anyway).
Including the rest of the circuit I doubt it needs more than 100 mA .
Piece of cake.
 
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