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For a push pull topology the primary winding need to be centre tapped. As for the secondary there is no need for a centre tap. The voltage at the secondary needs to be higher so that the chip can regulate when voltage drops due to load and also for battery voltage variation (11.5v-14v). If for...

You can use some household appliances such as heaters ( not including fan motor), cloths iron, toaster these all draw an amount of current depending on the input voltage to these appliances. Putting an ammeter in series and a voltmeter across the output terminals of the supply will tell you...

The noise is coming from the SMPS. When limit cuts in the smps tries to switch off and re- starts again. I don't know what your amplifier is consumig. I suggest that you increase the limit current to get rid of the noise. You must also check if your amplifier is clipping. Working your amp at...

Well in a way yes. The shorther the path with the signal to the mosfet gates the less likely to get false triggering due to induced capacitance and inductace in the traces. Try to keep high current paths away from small signal paths while designing the pcb. It is one reason I use a vertical pin...

Hi, for the current trafo you need to wind 80 double turns. It is best done with 0.15 or 0.2mm copper wire. You take two lengths of wire and wind them together. Thin wire can be found in relay coil. Regards Silvio

Put the volume control to minimum prior to switching off or you can add a mute circuit to the amplifier sensed on the mains supply swich. You can also add a crowbar circuit formed by a tyristor in series with a resistor to limit current. This will be sensed with the power switch and will...

Hi Steppler I took a look at the schematic again and C12 is a 470 uF. It is drawn the other way round. This controls the timing of the changeover between high and normal operating frequency. Sorry for the inconveniece.

That is a 470nf and is not polorised

I don't know what circuit you are using. Charging secondary capacitors present a dead short for the mosfets at statup. They may blow at times. You can do these adjustments as follows. 1) If you have an inrush current ntc resistor increase the value to 20 ohms. 2) put a couple of small inductors...

Regarding the pin header I guess the one on the last pdf works best(HF s/start & scr protection) when it comes to protection. It has been tried over and over again and never failed. The current trafo dia is from the ouside (12-15mm) using thicker wire than suggested (0.16-0.2mm) may not make it...

If you are choosing to use the Current transformer an option for a short circuit protection is available. The pin header however is different from the one using a current limiter and I am afraid to say that you have to make another one. The last version of pin header uses a high frequency...

Hi Bocko, I never used copper foil but If you have copper wire especially for the primary I think it is better. Just remember that the current in the primary is half that of the secondary. At 230v a consumption of 1200w is around 6 amps more or less. In my 1000w smps I used an ETD49 core epcos...

As for calculating the current density my suggestion is as follows. If the smps is intended for audio purpose then keep in mind that class AB amplifiers are around 60% to 70% efficient. So for 700w rms output you need 1000w from your smps. A class D amp is around 90% efficient hence you will...

Some fake chips refuse to start below 12v however you can make some changes to help with startup. 1, change the 10v zener to 12v 2. Change the 13v zener to 15v 3. Change the resistor coming from the auxiliary winding to from 200r to 100R. This mod helps with startup. As soon as the smps starts...

I see no output for a fan motor which normally is essential in an amplifier. This will also help if needing a separate 12-15v dc for the speaker protection relay. Ideally this part does not share a common ground with the preamp stage. Another thing I noticed are the diodes used for the...

All seems well. Just one small detail. The primary snubber capacitor usually has a pitch of 7.5- 10mm (ceramic type 1 or 2kv) and the snubber resistor is usually is of the 3watt type. Make sure that these will fit. I cannot determine the pitch used but assuming by proportion. As for the...

I don't see why this should not work. The small capacitor if fitted between the secondary and primary winding should be removed from one of the two power supplies. This will prevent any ground loops entering the high voltage end of the power supply. The reason is that they can react with each...

Hi again Benny, the high frequency startup is because the IR2153 does not have a soft start. Charging the secondary capacitors at startup present a nearly dead short especially if having more than 2000uf on each of the center tap windings. However starting the trafo with 3 times the frequency...

Hi Steve, that is a big improvement from your previous layout. I would like to point out some more improvements though. 1) you can add another pair of secondary caps making a total of 6. You can put them closer together These will give more punch on the base notes. 2) try to put the startup...

Hi Steven, I am seeing the layout and looks good but I think you wasted a lot of space on the pcb. I guess it could be made smaller, perhaps turning the output capacitors will get you there. This being a double sided pcb shall not be a problem. Using a pin header for the control circuit will...