600W Class D amp

[manojtm]

If this is a T157-2 1.5mm wire 35T=21μH.
What i missing?

Hi,

I used 17 SWG @1.5(1.422mm) it can wound 42T full on T157-2 core, and I used(40T) for 1800W design (56 deg. hot)

Regards
MANOJ

 

[manojtm]

Hi,

 

[thimios]

Hi,

What is the wire?
1mm?

 

[manojtm]

Hi,
17 SWG

 

[thimios]

Hi,
17 SWG

Thanks, 17SWG=1.422mm.

 

[badboy6120]

Hi,
17 SWG

Hello dear Manoj
what will happen if I wound 2 layer winding?
also can litz wire be used here?

 

[manojtm]

what will happen if I wound 2 layer winding?
also can litz wire be used here?

No problem

 

[badboy6120]

No problem

Thank you for your reply

I get some hisses at output even with input connected to *GND
is there any way to eliminate it?

 

[manojtm]

Hi,

I get some hisses at output even with input connected to *GND
is there any way to eliminate it?

Hiss noise happens GND(supply) not good or switching freq. not properly filtered ( second order filter = L+C )
Good GND will eliminate EMI.

Regards
MANOJ

 

[badboy6120]

Hi dear Monaj

this is the output of amp
11111.jpg - Google Drive

the frequency is about 190KHz just like the frequency of the amp and it's 1.3V p-p
is this the Hiss sound in my speaker's twitter??

this is the amp switching frequency
222222.jpg - Google Drive

if this is the Hiss source, How much voltages should it have that is acceptable?

 

[manojtm]

Hi,

Hiss sound in my speaker's twitter??

cut off freq. below 20KHz it will produce hiss/whistle sound on tweeter (fsw=190KHz L=? C=?) change the coil or cap value and test

No issue found on DSO graph

Regards
MANOJ

 

[badboy6120]

Hi,

cut off freq. below 20KHz it will produce hiss/whistle sound on tweeter (fsw=190KHz L=? C=?) change the coil or cap value and test

No issue found on DSO graph

Regards
MANOJ

tested with 3uf to 470nf for output cap and 22uH to 70uH for output coil
but the result is the same

 

[badboy6120]

Hi

is there another way to lower down the high frequency gain beside adding more turns on output coil?

the best way to eliminate hisses I found so far is to lower down the cut off frequency of the amp and that would be done by higher L in output but I don't want to decrease current capability on the load

My twitters are super sensitive and they will produce a bit of hiss even when I connect them to my class ab amp

 

[manojtm]

Hi,

is there another way to lower down the high frequency gain beside adding more turns on output coil?

did it it solve or not???

how you calculate cut off freq.

set cut-off freq. 40KHz L= 22uH and C= 680nF (FSW = 200KHz~270KHz)

Regards
MANOJ

 

[manojtm]

Hi,
and you can add another coil (5uH) or drum bobbin with 5 turn and c= 10nF/200V

Regards
MANOJ

 

[badboy6120]

Thank you sir Manoj for your helps
I'm currently working on my subwoofer amps, but no matter what I do I can't get more than 70V peak output voltage while my power supply rails are above 85V Dc (measured with multimeter)
shouldn't I get around 85V peak in output?
Thank you in advance

 

[kartino]

That unbalanced current draw from plus and minus is because of unbalanced amplification during higher output. Nirmally caused by bad quality part. Usually comparator.

 

[badboy6120]

That unbalanced current draw from plus and minus is because of unbalanced amplification during higher output. Nirmally caused by bad quality part. Usually comparator.

thank you for your reply
I solve that problem and now the amp working perfect but I want to get about 800W rms but I can not go higher than 600W
does that 12V chips supply cause this and I get only 73V dc(the rail voltages are at 85V DC) on mosfets at full power?
Should I increase power supply voltages?

 

[manojtm]

I want to get about 800W rms but I can not go higher than 600W
does that 12V chips supply cause this and I get only 73V dc(the rail voltages are at 85V DC) on mosfets at full power?

Hi

for 800W at 8R load supply should be +80v/10A -80v/10A. It is quite normal if you get 73v on clip at high level (normal power)increase current will can goes up to rail volt.

Regards
MANOJ

 

[manojtm]

Should I increase power supply voltages?

HI,

buss pumping effect more on half bridge topology so use full bridge for getting more power

+/-55v-14A full bridge will get 1500W 8R load
+/-55v-8A full bridge will get 800W 8R load

Regards
MANOJ