You would want inductors to have flat/constant inductance upto 4A I would say for your speakers that probably have a (narrow?) dip to 4 ohm and are rated 8 ohm. See what is highest rated you can get, that fits 🙂
If you're are mounting the amps right into the speakers, you may consider desoldering the complete output filters at all and run them filterless.
Could I solder wire wound inductors on the SMD mounting spot or do you reckon it will tear the spots off the PCB? Anyways, found the Wurth kind on Mouser but they only have them up to 2.5A. I will not be mounting the amps directly in the speakers. I like having an amplifier box I can tinker in.
Or TI filterless, 1nF&ferrite bead. But I don't know with rather tall 3 way speakers, maybe/probably 5 meter internal untwisted wiring and many aircore inductors, would that transmit a lot ? You can try and see if maybe nearby TV still receives all stations or parts of picture freezes etc. etc.
Edit: outputfilter is for emi reason, putting inductors or other components on leads above pcb will increase and not decrease emi I think
Edit: outputfilter is for emi reason, putting inductors or other components on leads above pcb will increase and not decrease emi I think
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For those who're interested in the counterfeit question, i made a post here:
http://www.diyaudio.com/forums/solid-state/115281-counterfeit-transistors-9.html#post4889168
showing different chip from the same lot with different pin1 indicators and other things.
Denmark:
OLE WOLFF ELEKTRONIK A/S
Roedengvej 25
DK-4180 Soroe
Denmark
http://www.owolff.com/index.html
Like:
http://www.owolff.com/Magnetics/datasheets/OWIRH105A.pdf
http://www.diyaudio.com/forums/solid-state/115281-counterfeit-transistors-9.html#post4889168
showing different chip from the same lot with different pin1 indicators and other things.
Denmark:
OLE WOLFF ELEKTRONIK A/S
Roedengvej 25
DK-4180 Soroe
Denmark
http://www.owolff.com/index.html
Like:
http://www.owolff.com/Magnetics/datasheets/OWIRH105A.pdf
Last edited:
I had a closer look at the resistors R27 and R28 on my board. They turned out to be 39K and 100K, meaning gain of 32 dB, and not 36 as I previously assumed. This made changing gain to 26 dB easier as it needed only replacing R28 = 39K to 20K.
One pad of R28 lifted and eventually fell off while desoldering, but I managed by using one end of R27. The copper is not exactly thick so much care needed if desoldering.
End result of reducing gain is lowered whining noise. But the noise is still there. I'm hoping that once I box it up properly and tidy up the wiring it will disappear or at least become low enough to be a non issue.
Also replaced the 330 uF caps with a "known" 470 uF cap which I have used in other projects. With the cap replacement I no longer hear the harshness that irritated me. Plus bass weight has improved substantially.
Hmm, changing 330 for 470 increases bass? Well, that must be some really crappy caps initially. Can't believe.
Earlier people recommended external speakerprotection circuits, because they had very bad experiences with "Tripath" chinese amps. I think the situation has become comparable to "Tripath" now and one certainly needs to be aware that speakers connected to these chinese "TI" ampboards could go to heaven/hell like in "Tripath" horror stories.
Finally found the correct documentation from none other than xrk (thanks xrk - you're a certifiable gem🙂):
See the second pic in Post #3823 for a close up:
http://www.diyaudio.com/forums/class-d/237086-tpa3116d2-amp-383.html#post3990270
Poking around with a multimeter helps determine that C10 and C12 in the circuit diagram in the above link are C16 and C25, respectively, on my board. This was further confirmed by continuity check of trace from C10 to L1, and C12 to L2.
My question: the 10R of the snubber needs to be grounded. Can I use the negative terminal of 220 uF power cap as ground as I can't find any other convenient ground pad? I've seen pics of others routing them to the underside of the board, but my board has no pads on the underside.
Alot of my 311x boards have these pins for inputs, like those on motherboards. What are the connectors called?
An externally hosted image should be here but it was not working when we last tested it.
Which ones ? On the Sanwu boards Molex KK 0.100 can be used (but you need a crimping tool). These are good connectors for inputs.
For speakers (current !) you can use Phoenix screw connectors with 2.54 mm pitch.
For speakers (current !) you can use Phoenix screw connectors with 2.54 mm pitch.
Ah, yes! Header pins. Googled that and found out they are called dupont connectors. Finally found them! Bought 100pcs.
Correction: to avoid confusion for anyone who might like to mod their PBTL boards similar to mine.
Again referring to the first schematic in Post # 3823, my board contains two inductors and not four as shown in this schematic.
The correct pins and capacitors on my board are BSPR (pin 30) corresponding to capacitor C10, and BSNL (pin 20) corresponding to cap C16.