Help:Transformer on 3886 chipamp overheating!

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OK so once i put the Rm in it worked! Amp is running fine so far but is there a burn in period, my crappy soldering or is it because the transformer overheated previously because the sound seems a little muddy and the highs are barely there.... I wish i could hear a well put together chipamp so i could get a reference to the sound.

when properly connected, these gainclones will work the fist time you power it up...a picture of how you did it will help.....

all these talk by the experts here mean nothing if you are unable to enjoy your amp....;)

this is how built my gainclone....it works, it is hum free...
IMG_3920a_zpsc146b4bf.jpg


Hi,
I have been following this thread for a while and I didn't want to get involve because I hated ground problems. Any way I already built 3 lm3886 and all have been hums free. All have 1.8 mv volts output offset and the sound it is super excellent. So attached it is a drawing that successfully I used to wired my amplifiers with good results. Just use it as a reference and hoping it will help you to fix your ground problem.

good job....:up:
for us diy'ers who actually build something, your ideas are easy to appreciate...;).


define "hum free"

when you don't hear it at listening position, or when you have to put an ear an inch away from the speaker to hear anything....
 
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And to repeat my previous statement: Pin 1 must refer to circuit ground, somehow. Otherwise, the input common-mode voltage is not controlled. If the source and the receiver are plugged into two different mains phases, you could have hundreds of volt of common-mode difference. The differential receiver won't like that too much. I suggest reading the THAT1200 differential receiver data sheet. I've attached the relevant figure for those too lazy to click on the link.
In most amps, the supply return is connected to the chassis at one point. That forms the Pin 1 reference.

~Tom

I re-read the THAT 1200 date sheet. I saw nothing that takes away from what Andrew & I wrote (pin 1 connects only to chassis).

In the RFI Protection section, I see:
Chassis ground should connect to circuit ground through one (and only one) low inductance path, usually at the power supply connector.

I would suggest that all the commons connect together at the Main Audio Ground and the to the chassis.
 
I have used them in the past
I have listed some of them in the past.
For you I will list the common ones again.

Signal Return
Zobel Return
Speaker Return
Power Ground
Zero Volts
Chassis
Protective Earth (or Safety Earth)

Thank you!
But, I have a couple of questions. How do power ground (the confusing ground word), differ from speaker return and zero volts?
Don't those receive the high current return from the speaker?
 
Power Supply Zero Volts is the wire/s and/or traces between the series connected smoothing capacitors of a dual polarity supply.
This is not an audio circuit. IT IS PSU.

Power Ground is the amplifier trace/s and/or wires that connect all the amplifier power to a common reference.

Speaker has two wire connection.
Speaker Flow and speaker Return.

Note in all the above descriptions none refer to any of the others.
 
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