My Blue Board is powered by SMPS adapter for HP notebook - 18,5V 6,5A 120W - and is working perfectly. I am not getting last drops of power from it with this PSU but with my highly efficient Tannoy studio monitor loudspeakers the sound is amazing. This was my first try with class D and I am encouraged to try something more ambitious like Hypex UcD180.
I think so. All TI datasheets I saw specified 220nF. Chip might not function completely as meant with other value (???):
BSPx AND BSNx CAPACITORS
The full H-bridge output stages use only NMOS transistors. Therefore, they require bootstrap capacitors for the
high side of each output to turn on correctly. A 220 nF ceramic capacitor of quality X5R or better, rated for at
least 16 V, must be connected from each output to its corresponding bootstrap input. (See the application circuit
diagram in Figure 19.) The bootstrap capacitors connected between the BSxx pins and corresponding output
function as a floating power supply for the high-side N-channel power MOSFET gate drive circuitry. During each
high-side switching cycle, the bootstrap capacitors hold the gate-to-source voltage high enough to keep the highside MOSFETs turned on
Those are used a lot. New NAD D3020 has a small stereo version the UCD102? The standard Ncore seems terrifying close to better most amps.
For +/- price of ucd180 however you could also buy LazyCats First One here on diyaudio... not D class, you'll need big heatsinks, but probably very good...
looking at icepower 300 asc frequency respons again shows that it's far less loadimpedance dependent then tpa3116 btw, so probably also feedback controlled like hypex?
For TI an optimised 4 ohm outputfilter (Q=0.7) has 20khz well within -0.5dB, that same output filter used with a 6 ohm load has ~+2 dB at 20khz, filter peaks a little Q has become 1.2, underdamped. Same filter used with 16 ohm load impedance, many speakers have even higher 20khz impedance, will peak excessively, not all peaking will be within 20khz audioband. Impuls respons, transient respons can almost look undamped, an impuls could almost look like a sinewave continuing. I have added a random picture for transient respons, you can check filter calculator mentioned here befor and see if you can find corresponding values to use because it is a SE calculator(your BTL 22uH,680nF, 8ohm load should show Q around 0.7)
Thanks. So, given the impedance needs matching to the LC filter should we do the calculations for the impedance at 20khz or just the normally quoted nominal impedance? For example my Mark Audio 10.3M driver appears to have an impedance around 20ohm at 20khz whereas nominal impedance is 7ohm. OTOH the frequency response is down some 5db at 20k (driver is a fullranger) so maybe that will compensate.
I can see this is a bit of a nighmare if you are going to be using different speakers with differing impedance curves!
Last edited:
Found two more cheap cases on aliexpress, as always purchase on own risk. My friend bought the 12$ and it was dispatched today, i might order next week.
0905 Full Aluminum Enclosure / mini AMP case/ Preamp box/ PSU chassis-in Consumer Electronics on Aliexpress.com
1005 Full Aluminum Enclosure/mini AMP case/ Preamp box/ PSU chassis power box-inOther Consumer Electronics from Consumer Electronics on Aliexpress.com
The smallest (0905) should fit perfectly with the blue board.
0905 Full Aluminum Enclosure / mini AMP case/ Preamp box/ PSU chassis-in Consumer Electronics on Aliexpress.com
1005 Full Aluminum Enclosure/mini AMP case/ Preamp box/ PSU chassis power box-inOther Consumer Electronics from Consumer Electronics on Aliexpress.com
The smallest (0905) should fit perfectly with the blue board.
For those of you who've replaced the gain resistors on the YJ blue/black board: did you have any trouble removing them?
Yesterday I set out to reduce the gain to 20 dB, which I assumed would be a 5 minute job... since this setting requires only the 20k resistor be replaced with a 5.6k (the 100k gets removed and left open), I really only had one through-hole component to replace. I probably spent 45 minutes on it.
My usual technique for removing through-hole components is to gently pull on one side of the PCB while heating the other side with the soldering iron. Doing that first resulted in the resistors separating from the leads. At that point, I could heat the remaining lead enough that it would "float" around in the molten solder---but it still wouldn't come out of the hole. I couldn't figure out why; this happened for both leads.
I tried sucking up excess solder with a solder sucker; I also tried cleaning up with de-soldering braid; I tried using a toothpick to push the leads through. I even tried using my soldering iron tip to force it through. All that, the leads were still stuck in the holes, and my soldering iron tip is now a little damaged.
Finally I just yanked out the leads with my needle nose pliers... this looked like I managed to pull off some of the conductor trace. So when I put the new resistor in, I just used a (sloppy looking) huge blob of solder.
I thought I'd be lucky if the thing still worked, but miraculously it does, although I have little confidence in those solder joints.
Anyone else experience this with the gain resistors or any other stock component for that matter? Even after the fact, I still can't figure out why I had such difficulty getting those leads out.
Yesterday I set out to reduce the gain to 20 dB, which I assumed would be a 5 minute job... since this setting requires only the 20k resistor be replaced with a 5.6k (the 100k gets removed and left open), I really only had one through-hole component to replace. I probably spent 45 minutes on it.
My usual technique for removing through-hole components is to gently pull on one side of the PCB while heating the other side with the soldering iron. Doing that first resulted in the resistors separating from the leads. At that point, I could heat the remaining lead enough that it would "float" around in the molten solder---but it still wouldn't come out of the hole. I couldn't figure out why; this happened for both leads.
I tried sucking up excess solder with a solder sucker; I also tried cleaning up with de-soldering braid; I tried using a toothpick to push the leads through. I even tried using my soldering iron tip to force it through. All that, the leads were still stuck in the holes, and my soldering iron tip is now a little damaged.
Finally I just yanked out the leads with my needle nose pliers... this looked like I managed to pull off some of the conductor trace. So when I put the new resistor in, I just used a (sloppy looking) huge blob of solder.
I thought I'd be lucky if the thing still worked, but miraculously it does, although I have little confidence in those solder joints.
Anyone else experience this with the gain resistors or any other stock component for that matter? Even after the fact, I still can't figure out why I had such difficulty getting those leads out.
If you are not planning to use the component anymore i usually very carefully cut the leads and fasten the PCB to something, then pull out the leads when desoldering, this is much easier.
What do you use to pull the leads out? I was trying just this, but when holding the lead with my pliers, the solder wouldn't get hot enough to melt. My pliers are metal, I assumed I was basically just heating them up.
So then I tried heating the solder up until it flowed, then quickly grabbed the lead with my pliers, while keeping the heat going, and still it stuck in the hole.
I'm far from an expert with a soldering iron, but I'm convinced there was something unusual about the way these particular leads were attached to the board.
If you cant pull it out the solder is not entirely melted, as it should be able to slide out. Usually you need to apply a little extra force hence many leads are bended in the end where its soldered and this can restrict the lead from sliding directly out of its place, has to be "fiddled" out, if it makes sense. I use some metal pliers also!
With the Lead-free solder, it does reflow better when you put a tiny amount of Lead-containing solder to help it flow more easily as Irribeo mentioned. Another trick is to dab a tiny bit if gel flux paste on the joint to get it to flow better. I use a 40W Metcal soldering iron that hears up quickly and reflows the Lead-free solder easily. Some less powerful irons might not conduct the heat as efficiently.
Please don't tell me that you are using plumbing soldering paste on electronic components.
I've never seen electronic solder paste.
Could you post a picture of it, please.
(or a link)