It's the same chip. No changes are needed to be done. The only differens between those two is that the TF has a insulated tab. The T-tab is not insulated, and are connected to V-
If you attach a LM3886T to a heatsink and dont isolate it (no plastic screw and isolation-plate) you will have 35V at the heatsink...
If you attach a LM3886T to a heatsink and dont isolate it (no plastic screw and isolation-plate) you will have 35V at the heatsink...
the LM3886TF is the insulated version and has a thermal impedance considerably higher than the LM3886T -- the difference is 1 C/W which means that you will need a heat sink almost double the surface area of that using the LM3886T -- or a fan.
I see no benefit in using the LM3886TF in DIY applications -- there is no sonic benefit, the chips are identical. Perhaps there is a metaphysical benefit -- you could get the same effect with a tumbler of gin.
I see no benefit in using the LM3886TF in DIY applications -- there is no sonic benefit, the chips are identical. Perhaps there is a metaphysical benefit -- you could get the same effect with a tumbler of gin.
Hello, thanks for the quick reply.
So no changes to the psu are needed atall - the snubber psu would be fine? and likewise brians amp circuit could be used without a problem aslong as the back plate was insulated?
no changes?
I am a total newbie, just want to make sure theres nothing else
jackinnj you talk as if I am chosing to use an LM3886TF as oppose to an LM3886T which is what I am actualyl using.
In regards to the thermal insulation does this mean that the LM3886T will only need half the size heatsink of a LM3886TF ?
So no changes to the psu are needed atall - the snubber psu would be fine? and likewise brians amp circuit could be used without a problem aslong as the back plate was insulated?
no changes?
I am a total newbie, just want to make sure theres nothing else
jackinnj you talk as if I am chosing to use an LM3886TF as oppose to an LM3886T which is what I am actualyl using.
In regards to the thermal insulation does this mean that the LM3886T will only need half the size heatsink of a LM3886TF ?
with a +/- 35VDC supply for the "T" version you need a heat sink with a thermal impedance of 2.8 C/W -- about 22 square inches of surface area. For the LM3886TF you have to increase the surface area very substantially. Here's a heatsink nomograph to help you out. This is not trivial.
An externally hosted image should be here but it was not working when we last tested it.
Hello,
Does this therefore mean that using LM3886T's would be a bad idea as a massive heatsink would be required?
Could I get away with not insulating the back plate if I isolated the heatsink from everything else, then there would be no problem of needing a bigger heatsink?
Does this therefore mean that using LM3886T's would be a bad idea as a massive heatsink would be required?
Could I get away with not insulating the back plate if I isolated the heatsink from everything else, then there would be no problem of needing a bigger heatsink?
matt09 said:anyone? Would it be ok if the heatsink was isolated away from grounds, etc to not insulate the tab so that I get more heat dissapated per square inch and not need a larger heatsink?
with heat sink compound and a mica insulator you add 0.2 C/W to thermal impedance.
for the Bridgeclone (which will throw off 120 watts around the clock into an 8 ohm load) I insulated the heatsinks. If you are just starting out this is not a good idea -- besides -- the thermal protection of the Overture series chips really does work.
jack
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