Its pretty easy once you start playing with it, there is also pretty good help files available to get to grips with the features....
Just for fun, let it show you the voltages for both capacitor banks on either side of the inductor to see what the inductor does. Observe RMS and max current riple on the first bank, then you see why we parallel caps there to make things last.
Just for fun, let it show you the voltages for both capacitor banks on either side of the inductor to see what the inductor does. Observe RMS and max current riple on the first bank, then you see why we parallel caps there to make things last.
Oh crap. One of the electrolyte capacitor on the power supply rail just leaked. It happens when I stuff everything into the chassis and wired both of the PCBs to the power supply. And I got DC offset of 15V!
Does it related to my earlier problem?
Does it related to my earlier problem?
Electrolytics don't like reverse voltages... But if they were these big cans we tend to use for Class-A, then they tend to be a little stronger.
Don't feel to bad. I once fried 4 brand new 10000uF 35V caps doing the same thing you did (luckily with no amp connected). I hope you are not putting speakers to that amp till it is fixed.
Don't feel to bad. I once fried 4 brand new 10000uF 35V caps doing the same thing you did (luckily with no amp connected). I hope you are not putting speakers to that amp till it is fixed.
I did the same and took out some unobtanium black gates. I was not a happy boy. But I did learn. That is goal number 2 of this silly DIY addiction. Build some great equipment on the cheap and learn something in the process.
I think the leaked capacitor contributed to the distorted sound I heard before.
I just received the capacitors yesterday...
I just received the capacitors yesterday...
Hey, look at the bright side. At least you didn't lie down resting on top of the 220V input leads with your arm. Good things, those RCDs 🙂
sorry i think this point needs to be pushed home a bit more, why are you still listening to your speakers with this faulty amp zyker? you should not have even had them connected when doing the setup testing, only when an amp has proven stable and has all the correct voltages everywhere, with no dc at the output, should you connect some test speakers, then and only then after that is ok should you connect your main speakers. otherwise, going by your comments here, it may not be the amps that are still distorted
One channel is running nicely while another is not.
The ridiculous offset only happened when I put them into chassis, at the same time I discovered that the one of capacitors was leaking.
During the test, the bad circuit had offset of 50mV, which is I think still reasonable thus why I connect the test speaker to it.
I hope you could lead me if I missed out something since I still new in this field.
The ridiculous offset only happened when I put them into chassis, at the same time I discovered that the one of capacitors was leaking.
During the test, the bad circuit had offset of 50mV, which is I think still reasonable thus why I connect the test speaker to it.
I hope you could lead me if I missed out something since I still new in this field.
Just a quick question. I'd like to shoot for 15W into 8 ohms. Will +/-18V rails give me that with the Mini-A? Lastly, what about using IRF644 instead of IRFP240 in this design? Thanks!
Re the problem with offset once installed in case, make sure isolators are not broken, make sure fastons are connected properly to bridges, I had a similar problem where one lug kept slipping off till I took some pliers to it.
I know it only makes for a 1.5dB difference, however that's not what I asked about. What I was after is the lowest possible rail voltage to achive 15 watts into 8 ohms. In addition, I plan to run just enough current to maintain 15 watts into 4 ohms. So, I'll be voltage limited at 8 ohms, and current limited at 4 ohms.
Don't we normally loose about 5 volts across the FET? So we would be looking at (30.98Vpp + 5)/2 = 17.99v rails. I'm I calculating this correctly? Thanks for you help.
I will let you know how much it drops when I am done adding the pre-transformer fuse and removed the ones between mu PSU and the amplifier boards. I need to measure it anyway to set up the clipping detector. My guess is you will be good on a 15V transformer, I think they use the 18's for the 25W alephs.
Member
Joined 2002
Clippin detector ? Serious ? You just ruined a nice sounding amplifier, the more JUNK you add to it the worse it gets.
Member
Joined 2002
Everything, why do you need it on a 10watt class a amplifier ? Like I said, it's a simple design meant for source in and a speaker.
Because it clips pretty easily and my speakers are only 15W jobbies, and pretty much irreplaceable.
I hope I can figure out what I just did, I did the fuse swap, but during testing of offset, an output fet started to smoke it's thermal paste. I pulled out the power cord, then I wanted to see if the fet was properly screwed in, but pulling on the PCB, it came clean off the FET, the bugger desoldered itself.
I hope I can figure out what I just did, I did the fuse swap, but during testing of offset, an output fet started to smoke it's thermal paste. I pulled out the power cord, then I wanted to see if the fet was properly screwed in, but pulling on the PCB, it came clean off the FET, the bugger desoldered itself.
Last edited: