Hi,
I was considering to regulate my power supply to an acceptable voltage for 4ohm load on a lm3886 from a 25.2vac transformer.
These are the options,
1) 3 LM317 paralleled per rail. (guranteed 1.5 amps per regulator)
2) 2 LM350 paralleled per rail. (guranteed 3 amps per regulator)
3) 1 LM2677 per rail. (guranteed 5 amps per regulator)
(I prefer to-220 chips to match the extra computer heatsinks I have.)
Any guidance on using these chips or any preferences?
I was leaning towards option 3.
Many Thanks,
Adrian
I was considering to regulate my power supply to an acceptable voltage for 4ohm load on a lm3886 from a 25.2vac transformer.
These are the options,
1) 3 LM317 paralleled per rail. (guranteed 1.5 amps per regulator)
2) 2 LM350 paralleled per rail. (guranteed 3 amps per regulator)
3) 1 LM2677 per rail. (guranteed 5 amps per regulator)
(I prefer to-220 chips to match the extra computer heatsinks I have.)
Any guidance on using these chips or any preferences?
I was leaning towards option 3.
Many Thanks,
Adrian
Hi,
the output current limit for a 3886 is specified as 7A minimum and 11.5A typical. These are peak values into complex loads.
With 4ohms speakers these peaks could/will be approached.
How will your amp draw these peak currents, from the capacitors after the regulators, or direct from the regulators?
Just some thinking for you to do and arrive at some conclusions before committing to a particular regulator design.
the output current limit for a 3886 is specified as 7A minimum and 11.5A typical. These are peak values into complex loads.
With 4ohms speakers these peaks could/will be approached.
How will your amp draw these peak currents, from the capacitors after the regulators, or direct from the regulators?
Just some thinking for you to do and arrive at some conclusions before committing to a particular regulator design.
Hi Andrew,
I was thinking of having large caps (47000mf + 4700mf + 100uf(beside the chipamp)) after the regulator to smooth ripple and to cache extra current for the chipamp.
This is part of my 5.1 amp project, so I was figuring that I would not be running the chipamps to their full potential.
I saw your last posting about using two postive regulators verses a pos plus a neg regulator combo. That was something I wasn't sure about, but I trust your recommendation and will go with 2 pos - also makes bulk chip purchases easier
.
Any opnions on the regulator chips?
Adrian
I was thinking of having large caps (47000mf + 4700mf + 100uf(beside the chipamp)) after the regulator to smooth ripple and to cache extra current for the chipamp.
This is part of my 5.1 amp project, so I was figuring that I would not be running the chipamps to their full potential.
I saw your last posting about using two postive regulators verses a pos plus a neg regulator combo. That was something I wasn't sure about, but I trust your recommendation and will go with 2 pos - also makes bulk chip purchases easier
.Any opnions on the regulator chips?
Adrian
My recommendation is to trust the designers who originally suggested the twin positive regs for a dual polarity supply.
Your output caps should be able to source the peak currents demanded. That then places the regulators in an easier regime. They only have to meet average demand. Your 5A may just about do for a 6channel amplifier, but might be stretched. Be prepared to having to build a second pair of regs to ease their workload.
Your output caps should be able to source the peak currents demanded. That then places the regulators in an easier regime. They only have to meet average demand. Your 5A may just about do for a 6channel amplifier, but might be stretched. Be prepared to having to build a second pair of regs to ease their workload.
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