need help or a finger in the right direction ! bought 4 lm3886 modules that look quite good (see pics) sound prety good singular, and unfortunately cant find a diagram ,replaced all resistors with hand matched ! replaced chips ! removed zobel networks and replaced it with 0.1r matched resistors !joined up as in diagram with 2 x 24v smps, replaced zobel on + binding post ,,,,,the problem is just a bad popping sound from test speakers and have lost a couple of chips so far,,,,, ps does seem ok without input signal as no popping,,, any help welcome
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Do not wire the outputs together, it may cause unwanted issues.
hi can you explain ? thanks
How well matched are the gain setting resistors?
basically identical,,all matched on home made jig consisting of a low voltage through different resistors and taking mill / volt reading with dmm
Are you trying to parallel 2 separate lm3886 amplifiers/boards ? I tried that once long time ago, I remember it did not work. To many issues, ground loops/problems, gain will never be identical .
Good luck.
yes ! i have suceeded before with the simpler xy boards with no problems
You could easily bridge them, add drv134 and adjust the power supply voltage so it could go with your speaker impedance. Will give you 100w in 4 ohms and 120w in 8ohms.
Again , I don’t think that paralleling 2 boards will work, the idea is to parallel the chips and not the boards.
Again , I don’t think that paralleling 2 boards will work, the idea is to parallel the chips and not the boards.
You must add 0.1 ohm on each output before paralleling . Check first if you have very low difference ,offset voltage & ac voltage at highest output level .
yes ! i have replaced the zobel network on each module with the 0.1r and reattached the zobel directly on positive binding post
You could easily bridge them, add drv134 and adjust the power supply voltage so it could go with your speaker impedance. Will give you 100w in 4 ohms and 120w in 8ohms.
Again , I don’t think that paralleling 2 boards will work, the idea is to parallel the chips and not the boards.
thanks for your input ! i have previously made a bridge setup as you mention with drv 134 with good success ! to my ears parallell lm3886 may not be as powerfull as bridged but does have a fuller sound ( all subjected ) ime experimenting with these boards as they do sound sweet singularly ! and at the end of the day if this project is a no no i might go bridged
Lm3886, you can parallel but not recommended for bridge
Taming the LM3886 Chip Amplifier
Taming the LM3886 Chip Amplifier
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Plz read LM3886 - Application Note 1192 - Reference Design here:Lm3886, you can parallel but not recommended for bridge
Taming the LM3886 Chip Amplifier
http://www.ti.com/lit/an/snaa021b/snaa021b.pdf
There are a lot of great designs around bridged lm3886 , even lm4780.
Yes , you dissipate four times more power than a single , but keeping the same load impedance. If when bridged the load is double impedance, than total Pd becomes twice higher then a single all providing twice more power . By this Pout/Pd remains the same , each IC dissipating the same as running in single. This why the load impedance when bridged must remain higher than 8 ohm.You can do bridge, yes.
but it is not recomended because of the power consumption, its also in the link you provide section 3.
Better go for parallel or bridge parallel.
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basically identical,,all matched on home made jig consisting of a low voltage through different resistors and taking mill / volt reading with dmm
Yes, it's not certain he's able to measure them accurately enoughFor parallel amps, resistors which defines amplification on the LM3886 should be 0.1%,
after that there are no problems with it. Load share resistors on the outputs are mandatory.
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