I have a problem i dunno the solution to.
Why is my D-Amp acting like it doesent work properly (weird noises and beeping) when connected to an alone speaker driver and not when connected to speakers containing crossovers ?
When connected to speakers with crossovers it works properly.
I have tried a zobel RC network with no luck, i used the same values as in Pat Allen´s schema for the PB12 replacement amp.
How many µH is the output filter toroid coil from a puter ps ?
Why is my D-Amp acting like it doesent work properly (weird noises and beeping) when connected to an alone speaker driver and not when connected to speakers containing crossovers ?
When connected to speakers with crossovers it works properly.
I have tried a zobel RC network with no luck, i used the same values as in Pat Allen´s schema for the PB12 replacement amp.
How many µH is the output filter toroid coil from a puter ps ?
It doesent go unstable. It doesent care if its a 8ohm speaker or a 1ohm speaker, as long as theres a crossover in it.
With a bare driver it seem like shifting freq and stuff, the fets gate waveform changes between freqs and kinda looks like pwm from a freq close to the osc freq.
The feedback is taken after the op lc filter but before the output cap.
With a bare driver it seem like shifting freq and stuff, the fets gate waveform changes between freqs and kinda looks like pwm from a freq close to the osc freq.
The feedback is taken after the op lc filter but before the output cap.
That's what I told you Tekko, your feedback loop is unstable. Your cutoff of your output filter is close to a pole of your feedback network. When you add a crossover, this will add some capacitive and inductive component to the load, that change the cutoff frequency of the output filter. Play with a small capacitor in parra of your feedback resistor and remove the 100pF to ground in your loop, this will help you.
Fredos
www.d-amp.com
Fredos
www.d-amp.com
You need to know the 'Al' value of the core in nH/turn^2. This is often quoted in the manufacturer's data sheet.
For example, if the Al value was 1uH per turn-squared, then the required number of turns to get 20uH would result from the equation N^2 =L/Al therefore N^2 = 20, so you would get 16uH from 4 turns, or 25uH from 5 turns.
In reality the Al value is likely to be lower than this so you'll be able to adjust the number of turns to get closer to your desired value.
If you don't know the Al value, and you have an inductance meter, then simply wind 20 turns or so on the core, measure the inductance, and apply the equation above to determine the number of turns to get your desired inductance.
For example, if the Al value was 1uH per turn-squared, then the required number of turns to get 20uH would result from the equation N^2 =L/Al therefore N^2 = 20, so you would get 16uH from 4 turns, or 25uH from 5 turns.
In reality the Al value is likely to be lower than this so you'll be able to adjust the number of turns to get closer to your desired value.
If you don't know the Al value, and you have an inductance meter, then simply wind 20 turns or so on the core, measure the inductance, and apply the equation above to determine the number of turns to get your desired inductance.
Try micro metal material -2 or -6, that's what give the best result. At least KoolMu material too.
Try a small cap over the feedback resistor, ie the one from output to comparator.
Fredos
www.d-amp.com
PS. If you change the core material, you will change the pole of your feedback loop...Always think about this!
Try a small cap over the feedback resistor, ie the one from output to comparator.
Fredos
www.d-amp.com
PS. If you change the core material, you will change the pole of your feedback loop...Always think about this!
Nevermind. D-Amp back to the dead.
Because of a faulty connection, the gate drivers i had left blew when i tried to run the amp @ 30+ volts.
This time i dont have any parts left to repair it again, i blew the gate drivers i had left before i noticed the mistake done in the wiring.
I´ll have to order new gate drivers yet again.
I gonna add a output filter coil to the order this time, which should i take ?
These ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011473.htm
Or these ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011475.htm
Or these ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011474.htm
Because of a faulty connection, the gate drivers i had left blew when i tried to run the amp @ 30+ volts.
This time i dont have any parts left to repair it again, i blew the gate drivers i had left before i noticed the mistake done in the wiring.
I´ll have to order new gate drivers yet again.
I gonna add a output filter coil to the order this time, which should i take ?
These ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011473.htm
Or these ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011475.htm
Or these ? http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2011474.htm
None of these...You should have between 25uH and 50uH for your circuit with at least 5A of current ripple if you whant to use it a 30V into 4 ohms..
Fredos
www.d-amp.com
Where are you? I can supplie you fews of ours coil, 25uH at 10A already made.
Or if you whant to have it for bigger amp, we have 47uH at 25A and 50A too...But $$$
Fredos
www.d-amp.com
Where are you? I can supplie you fews of ours coil, 25uH at 10A already made.
Or if you whant to have it for bigger amp, we have 47uH at 25A and 50A too...But $$$
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