600W Class D amp

[AudioSan]

60V peak at the output is not 900Wrms@4ohm.

60Vpeak/1.414=42.4Vrms.
42.4*42.4/4ohm=449Wrms@4ohm.
peak power is useless.

 

[manojtm]

60Vpeak/1.414=42.4Vrms.
42.4*42.4/4ohm=449Wrms@4ohm.
peak power is useless.

Hi,
i don't understand why you again divide 1.414. It is not a supply volt.

Regards
MANOJ

 

[manojtm]

Hi,

iNuke3000 spec.
2R 1500W 4R 900w (class D amp with SMPS supply rail +/-78V)
so sq.root (900*4)=60v. is it wrong
iNuke6000 using +/-83vDC it was a class D full bridge

Regards
MANOJ

 

[manojtm]

Hi,
iNuke6000 output volt was 55v @4R load Max. (Bridge it is 110v) {said wattage is 3000W@4R}

Regards
MANOJ

 

[AudioSan]

Hi,
i don't understand why you again divide 1.414. It is not a supply volt.

Regards
MANOJ

so you don't understand the differnce between peak voltage and rms voltage? that explain why you seem not to understand that threadstarter is talking about average power and you again and again refering to peak power

 

[manojtm]

so you don't understand the differnce between peak voltage and rms voltage?

Hi,

I know, but in audio band 20Hz~ 20KHz you tested with resistor load different output voltage will get, the same way tested with speaker it is different.All speakers(except Pro Audio) are noted is FTC rating only not true RMS. If you need accurate true RMS provide more supply and supporting MOSFET.
+/-100v supply rail will get 80vpp @clip true RMS is 57v = 800W@4R RMS

Regards
MANOJ

 

[AudioSan]

now you're getting it.
and to get volt rms, you take Your peak voltage and divide it by 1.414.
as threadstarter said. he got 70Vpeak on the output.
70/1.414=49.5Vrms
49.5*49.5/4ohm=612Wrms@4ohm.

 

[manojtm]

explain why you seem not to understand that threadstarter is talking about average power and you again and again refering to peak power

Hi,

RMS value is an effective value of AC quantities which need to be considered for different
types of calculations and assumption and it is also equivalent to its DC value.

Regards
MANOJ

 

[manojtm]

Hi,

10V DC connected 2R load 5A P= 50W
10V RMS AC connected 2R load 5A P= 50W
10V RMS AC Means approx. 14.14V (this with load only)

Regards
MANOJ

 

[manojtm]

Hi,
peak vs RMS

Regards
MANOJ

 

[AudioSan]

is there a reason for this posting?
you don't need te teach me about peak and rms. but you need to stop mixing them.

 

[badboy6120]

Thank you dear monaj for your helps
here's the latest schematic
any problem?
AUD600.Ver.2.jpg - Google Drive

 

[manojtm]

Hi,

ok. only thing you can increase resistor value (3K3/5W) to 8K8/2W.a good quality op-amp will consume less current. from 90v 8k8 can give 10mA TL071&72 will consume only 2.5mA Max. so both will take 5mA.

Regards
MANOJ

 

[manojtm]

Hi,
badboy6120 only for you,
please measure output volt without any load on current configuration.

a) +/-85v supply rail 100Hz pure sine wave 1.4vpp signal
b) +/-85v supply rail 1000Hz pure sine wave 1.4vpp signal

Regards
MANOJ

 

[badboy6120]

Hi,
badboy6120 only for you,
please measure output volt without any load on current configuration.

a) +/-85v supply rail 100Hz pure sine wave 1.4vpp signal
b) +/-85v supply rail 1000Hz pure sine wave 1.4vpp signal

Regards
MANOJ

Hi sir monaj
thanks alot for helping
I will do that tonight and share the result but without any load the rail voltages goes to +-90V and 85V is when the amp is under heavy load

 

[badboy6120]

Hi,
badboy6120 only for you,
please measure output volt without any load on current configuration.

a) +/-85v supply rail 100Hz pure sine wave 1.4vpp signal
b) +/-85v supply rail 1000Hz pure sine wave 1.4vpp signal

Regards
MANOJ

with +-90V supply and feeding a 1.4V peak to peak sine wave I get about 108V peak to peak with 100Hz and 1khz(without any load)

 

[badboy6120]

Good News
I increased the rail voltages to +-110V and now I could get more than 1100W RMS output power

 

[badboy6120]

Hey guys
What's the best solution to reduce mosfets overheating?
parralleling mosfets?
or go for full bridge?

 

[badboy6120]

I manage to controll the mosfet overheating by using seperate heatsink for mosfets and remove the isolator between mosfets and heatsink
I test this amp for more than an hour with more than 1KW rms in output by 100HZ sine wave

 

[badboy6120]

Hey guys
I was wondering if the new supply votages(+-110V) will cause any damage to the mosfets (BVDSS)
my mosfets are 4IRFP4227
I test this amp with more than 1KW RMS output for an Hour but I don't want to damage the mosfet because of the drain source breakdown voltage
any help would be appriciated