I will test it this week or next. I have planned it fr the output of atleast 1200 watts with less than 1%thd with 3pairs of irfb4227. On 75 volts rail on 2ohms load
in my first test without using buffer transistors i tested it with one pair. i did not test this on constant resistor load. i directly test it on a speaker.
i got no noise not on start up or while turning off.
i will get the buffer transistors this week n after testing it i will post all the results.
this board it based on mixture of iraudamp9 and iraudamp7d.
single sided board and all thru hole components except ic and buffer transistors.
decoupling was not an issue for me. only issue i face was that 10ohm resistor on zobel network was going really hot. don't know why! any guidance on it???
Regards
Sabir
If any carrier is getting through the output filter the zobel will cook.
Revisit your output filter or check for carrier after the filter on a scope.
You might need to increase output filter choke or capacitor.
I used 470nf capacitor and 27uH choke and still got a little carrier out past the filter.
I had 2 designs one with gate driver IC tC4420 and the other that used a BD243/244 pair. Either of these gave about 6 amps gate drive.
The irs2092 is quite weak for driving mosfets and the best it can do is one pair of irfb4019's.
Signs of lack of gate current is resetting before the amplifier gets loud.
The lack of drive current turns on the mosfets too slowly and the 2092 thinks there has been an over current event and resets.
i will be using zxtp25100 and zxtn25100 as used in iraudamp9.
i used 22uh but as i did not have much time for testing it, i did not test it with scope. this sunday when i will get my hands on the buffer transistors i will have a full test done.
i will also increase the inductor value to look at the changes.
thanks for the guidance
Regards
Sabir
Also i forgot to ask
What might be the problem if only one of the RC snubber resistor gets hot?
Any guidance?
Using a 10k trimmer for frequency adjustment instead of 1k is not likely to cause damage, when everything else is fine.
You might have another hidden error somewhere.
Now after the amp is dead you have ahead the painful way of checking all
components if they have the right value, right orientation and if they are undamaged. Annoying - but never give up.
For first powering up you should either use an supply with a current limit which can be set to 1A.
If such supply is not available, use light bulbs in the plus & minus rails, i.e. 40W/230V or alike.
After powering up, error search can start with an ordinary multimeter checking all auxiliary supplies of the IRS.
You might have another hidden error somewhere.
Now after the amp is dead you have ahead the painful way of checking all
components if they have the right value, right orientation and if they are undamaged. Annoying - but never give up.
For first powering up you should either use an supply with a current limit which can be set to 1A.
If such supply is not available, use light bulbs in the plus & minus rails, i.e. 40W/230V or alike.
After powering up, error search can start with an ordinary multimeter checking all auxiliary supplies of the IRS.
used a 40w bulb for all testing. it was my mistake first that i did not use 1k trimmer.
and i find it very difficult with this board. so i think i will be using for test purpose the initial design of iraudamp9 daughter board. will give it for printing soon
did all the things i could still no go.
i will see if i could bring this thing back to life or i will try out with ir's initial design..
hope to have guidelines from all of u for further problems if any
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.