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amichalik 9th June 2006 02:33 PM

LM3886 Low Output Level
Yesterday I replaced my "original" LM3875 BrianGT boards and power supply with new LM3886 boards from Brian with the snubberized power supply, primarily as I'm running 4 ohm speakers and I wasn't thrilled with the performance of the LM3875 in that application.

So, I "rebuilt" my gainclone, using just the transformer and case from the LM3875, rewiring the whole thing at the same time.

After checking to make sure I wasn't going to burn anything to the ground, I installed the LM3886 into my system and let it warm up for an hour or two.

When I went to listen to the LM3886, the sound level was much lower than the LM3875. For example, normal listening level with the LM3875 was about 5 out of 10 (or 11 if you're using the Spinal Tap scale), whereas the LM3886 had to be turned up to 10 to get the same sound level.

What on earth have I done?

amichalik 9th June 2006 09:29 PM

No one has ideas to help me out?
Does anyone have any ideas what might have caused this drop in output level?

Could I have used the wrong resistors in the wrong location? Or is there anything that I might have disrupted in the power supply?

I need any/all thoughts and suggestions. Thanks!

Netlist 9th June 2006 09:32 PM

I haven't looked at the circuit in detail so here's only some guesswork.
Look at the input network and feedback resistor. I believe these are partly responsible for the gain.

/Hugo :)

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