I have a fried Arcam amp and i want to use the transformer at least for my chip amp. The transformer has three wires one blue and two orange. The voltage from blue to orange is 28v. I think this is in the ball park for LM3886 power supplies right? From the looks of the schematics this power supply will only make a mono amp, is that right? i'm unsure of most of this 
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I was thinking of tring to chop the rectifier circuit out of the arcam, preserving the nice circuit board, but i think it looks different, Would i be able to use this?
.I was thinking of tring to chop the rectifier circuit out of the arcam, preserving the nice circuit board, but i think it looks different, Would i be able to use this?
An externally hosted image should be here but it was not working when we last tested it.
Your Transformer sounds like a 2 x 28v AC Transformer which will rectify to about 42v DC which is the very max limit of the Chip and you will probably have some heat issues....
I suggest that maybe you check out the TDA7293 , It is a 100W Chip with a DMOS Output stage and can handle up to +/-50v, They are good sounding chips with more output power than the LM series chips....they are a bit harder to to use but there is a PCB design in the datasheet that works OK....
Cheers
I suggest that maybe you check out the TDA7293 , It is a 100W Chip with a DMOS Output stage and can handle up to +/-50v, They are good sounding chips with more output power than the LM series chips....they are a bit harder to to use but there is a PCB design in the datasheet that works OK....
Cheers
I agree on the transformer wiring but 2 x 28VAC = 42VDC???? Not sure what rectifier/filter configuration you are thinking of.
If you used one side of the secondary I'd expect about 38VDC (no load) for a full wave bridge.
Using both sides gets either 76VDC or ±38VDC depending on what you do with the center tap.
If you used one side of the secondary I'd expect about 38VDC (no load) for a full wave bridge.
Using both sides gets either 76VDC or ±38VDC depending on what you do with the center tap.
what about the lm 3886 chip?. it will [ unless l remember wrong] take up to about 50v for an output of approx 65w also there are numerous threads on using it , perhaps you should take a look at nuuk's site at decibel dungeon sorry l cant give you the link just punch it into google and it will take you there.........
hope this helps, cheers TC
The LM3886 has a max Loaded Voltage of +/-42v which is about what a 2x28v transformer puts out...It will probably drop a few Volts when loaded but heat will be an issue....
My very first Chipamp used a LM3886 and I tried to use a 2x28v Transformer with it but after about 10 minutes of playing the thermal protection would kick in and I used a HUGE heatsink (about 8 in wide 4 in tall and 1.5 cm thick with about 15 1mm Fins that stook out about 3 in)
I thint tried it with a 2x18v transformer and I was able to actually put 2 LM3886 chips on the same heatsink and drive 4 ohm loads without really heating up that much....
I personally would Opt for a lower Voltage Transformer or use a different chip....
My very first Chipamp used a LM3886 and I tried to use a 2x28v Transformer with it but after about 10 minutes of playing the thermal protection would kick in and I used a HUGE heatsink (about 8 in wide 4 in tall and 1.5 cm thick with about 15 1mm Fins that stook out about 3 in)
I thint tried it with a 2x18v transformer and I was able to actually put 2 LM3886 chips on the same heatsink and drive 4 ohm loads without really heating up that much....
I personally would Opt for a lower Voltage Transformer or use a different chip....
Blue is the common center tap, the 2 orange leads are the 2 secondary windings. You should get the same AC voltage from blue to either of the 2 oranges, but they're out of phase.
Search the forum for the various rectifier modes, half and full wave, to compare to how yours is configured. Power supplies are a hot topic around here.
Minion: thanks for the clarification. You are quite right.
Search the forum for the various rectifier modes, half and full wave, to compare to how yours is configured. Power supplies are a hot topic around here.
Minion: thanks for the clarification. You are quite right.
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