What is the most current opinion on the blue black board, IIRC was nicknamed YJBB from Yuan Jing? Is the potless red one still considered a better implementation? Also what is the search keyword for connector that goes to the input signal socket for that board?
I agree with the commendation for ayanhu81, have bought from them and it's very satisfactory.
I agree with the commendation for ayanhu81, have bought from them and it's very satisfactory.
I have bad luck with the small red mono 3116 boards. They hiss and are wrongly configured as slave at very high gain with incorrect resistor values. Blue 3118 Sanwu mono boards are configured in Master and can easily be lowered in gain to remove hiss.
If you are curious what different amps sound like in virtual audition you may like this
http://www.diyaudio.com/forums/solid-state/295286-virtual-audition-very-simple-quasi-mosfet-amp.html
http://www.diyaudio.com/forums/solid-state/295286-virtual-audition-very-simple-quasi-mosfet-amp.html
It took some time, but I corrected the mounting of the modules and redid the wiring. Using microphone cable makes a LOT of difference! Also redid the layout as suggested in here, much better this way!
(please don't criticize my soldering skills too much
)
Do notice that I should have connected the shielding of the cable to the black wire inside it, this removes the last bit of remaining hum when I do it on-the-fly with a crocodile clamp.
Still waiting on my speaker terminals, so I can add that last bit of wire in there and properly use it and test it out
(please don't criticize my soldering skills too much
)Do notice that I should have connected the shielding of the cable to the black wire inside it, this removes the last bit of remaining hum when I do it on-the-fly with a crocodile clamp.
Still waiting on my speaker terminals, so I can add that last bit of wire in there and properly use it and test it out
Nice improvements! Thought, if you put the aluminum angle on the outside of that mounting board you could shorten the leads even more. And, the amp footprint gets even smaller. I would also mount boards to a strip of aluminum or copper or heatsink to absorbed some of the heat and get it away from the amp board? I used a strip of aluminum and just put some JBweld under chip and glued to aluminum. Makes quite a difference. Holes to outside the case would help reduce trapped heat too. Just a suggestion.
Ah the famous JBWeld. Good and kind of universal stuff but not available in Europe ! Got it via a US connection. However Arctic makes some nice thermal glues that are better suited for the job and they are not too expensive. JBWeld has metal particles in it which could be somewhat finer for mounting heatsinks on chips.
Thanks for sharing your photos, Blamm.
If anyone is interested, I did some scope and spectrum analyzer measurements of the power rail supplying one the Sanwu Blue TPA3118 modules, under various audio signal input conditions. Now to figure out the implications my observations...
If anyone is interested, I did some scope and spectrum analyzer measurements of the power rail supplying one the Sanwu Blue TPA3118 modules, under various audio signal input conditions. Now to figure out the implications my observations...
Have been listening to the small blue Sanwu 3118 mono boards for about a week now. I got 4 of them driving a pair of B&W P5 floorstanding speakers. They sound surprisingly good. No caps are either bulging or blown. It is very important to lower the gain, though. Even at above average listening volume they do not get excessivly warm. Very happy with these after trying so many 3116 boards with either a hiss or bad configuration
Maybe interesting when you want to measure outputs, info counts for class D as well....
http://www.metatech.com.hk/appnote/apogee/pdf/TestingNote.pdf
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I'm no expert, but I think you are apply linear-amp concepts to something that isn't a linear amp anymore.
switchers act instantly and its not about 'power stores' like it is for linear amps. again, I could be wrong, but I suspect that you won't see the improvement you are seeking.
the modules are what they are. change chips and such if you want more than they offer
If I understand what I'm seeing in that photo, you've put a big bank of large electrolytic caps inline with the audio inputs for each board.
I'm not sure what its going to do, but I doubt it will work as you hope.
Perhaps you are confusing and combining two different things.
First, that too-small coupling caps in the audio input path can roll off the low-end.
Second, that voltage sag on the power rails can distort amp output, at times of high-power, especially when playing low frequencies.
The first would be addressed by shorting the input caps on the board and then using suitable caps in series. Whatever constitutes suitable type of input cap, I'm pretty sure the value is much less than you have there. It may also be possible to eliminate the caps entirely, as long as you can be sure that the input has no DC component.
The second might be helped by your putting big electrolytic caps in parallel with each other, and the load between the positive and negative power inputs on each board, as close to the board as possible. Having a suitably sized power supply is probably a good first step though.
Edit: Looking even more closely, it appears like you may have the power and speaker connections for the module on the left quite wrong.
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There is a rather wacky optical illusion in your photo. Making it appear that power connections are wired to the audio input on the left amp.
Other than that..... Your cap bank should be across the power connections of the amps, as suggested by "easp". Too much cap might cause your PSU problems as it rushes to fill them.
Page 99I actually had some extra components laying around so I went ahead and ruined the magic of these 3118pbtl so here is a subjective opinion.
Initial impressions were: yes the highs does sound better, more smooth. The mods did eliminate the high pitch whine that can be heard with no music playing. I can tell which speaker has the modified board in a blind test pretty quickly. But was it worth the time and ~$18/block? I do not know yet, right now I am thinking no.. I need some time to listen to them some more.
Have been reading this whole thread to dust up mods. Found this the most interesting. Im actually very happy with the sound of the boards from stock. Except gain which I changed. But I also have this high pitch sound when nothing is playing. Barely audible, but I know its there. Which mod is the most likely to fix this? By the way. Couls I leave the stock SMD caps and put one big ekstra on power input instead?
