900W H-class PA Amp with Limiter

Hi Apex

Hi apex.
H900 watt project is very good. It really works very well and as well as output is very Punchy and clear.
I am confused in one thing, may be this is a problem that u might know.
I need the step driver test up procedure.

when we turn the amp on then the voltages on fuses are 55 +ve and -ve.
When we increase the volume voltage quickly goes upto 110 +ve and -ve on the fuses.
When we descrease the volume the voltage aren't goes down it remains the same on high voltages as 110 +ve and -ve on both sides. when we switch it off and turn it on again then voltages remain stable such as 55 +ve and -ve. but i think that the voltages should be vary with the volume controll. Plz help me.
I look forward to see ur reply

Thanks

Khalsa
 
Hi apex.
H900 watt project is very good. It really works very well and as well as output is very Punchy and clear.
I am confused in one thing, may be this is a problem that u might know.
I need the step driver test up procedure.

when we turn the amp on then the voltages on fuses are 55 +ve and -ve.
When we increase the volume voltage quickly goes upto 110 +ve and -ve on the fuses.
When we descrease the volume the voltage aren't goes down it remains the same on high voltages as 110 +ve and -ve on both sides. when we switch it off and turn it on again then voltages remain stable such as 55 +ve and -ve. but i think that the voltages should be vary with the volume controll. Plz help me.
I look forward to see ur reply

Thanks

Khalsa
Voltage on the fuses is 55V, and if you measure with DMM, voltage in DC range can't be over 70V with high volume level, becouse step on 110V is fast and short, and you never can measure 110V on fuse. Something is wrong on your amp, can you post some pictures, maybe I can see mistake.
Regards
 
hi apex

Hi apex I attach the photos
plz have a look.
 

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Hi apex i am using ssh70n10a mosfet it contans 70 ampere 100volt.

Blue wire in input ground. i connect direct to the PCB.
Output is clear no problem.
plz chk this out.
Regards
Khalsa
 

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Last edited:
hi apexaudio
greetings amplifier rocking want to finish packing it
1 are 10 10000 uf condensers for i channel or both
2 any preamplifier with base treble for this amplifier
will mj 15024 mj15025 increase power and safety 4 pairs will sound quality
be same
3 can you please tell me torridal diameter and height dimensions powering
both channels
thanking you
andrew lebon
 
hi apexaudio
greetings amplifier rocking want to finish packing it
1 are 10 10000 uf condensers for i channel or both
2 any preamplifier with base treble for this amplifier
will mj 15024 mj15025 increase power and safety 4 pairs will sound quality
be same
3 can you please tell me torridal diameter and height dimensions powering
both channels
thanking you
andrew lebon
1 PSU PCB with 8x10000uF is for stereo
2 I suggest only power amplifier in case, and preamp, mix, x-over... in another case.
3 Torridal diameter 200mm height 80mm for stereo amp in 2U case.
Regards
 
@apexaudio

how do you think about this simple linear Class H BJT Step driver circuit is this PA Amp ?

is it possibile to use this linear Class h Step Driver in quasicomplementary output stage too ?

without known problems compare to switching Class H Step Driver with IR2117 IC and Mosfets ?
 

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@apexaudio

how do you think about this simple linear Class H BJT Step driver circuit is this PA Amp ?

is it possibile to use this linear Class h Step Driver in quasicomplementary output stage too ?

without known problems compare to switching Class H Step Driver with IR2117 IC and Mosfets ?
Try to find schematics or service manuals of some commercial PA amplifier with quasicomlementary nmos output stage (AB or H class), if this amplifier exist you can see solutions for your amp.
Regards
 
Try to find schematics or service manuals of some commercial PA amplifier with quasicomlementary nmos output stage (AB or H class), if this amplifier exist you can see solutions for your amp.
Regards

yes this Amplifier exist, have working some years ago for this company and sold a lot of pcs. from this model to european PA clients,

but heavy analaog amplifier is since 3 years obsolet in market by european clients.... and my previous factory dont have since today SMPS, this model dont like continous maximum Subbass output power, output devices can failed.

I dont like BJTs in output stage against bad experience, often different BJT amps failed with continous high output power

with hundreds of Class D and 50 pcs. sample NMOS amps +/- 100 V Rail no known problems compare to BJTs amps

very popular is class D in market.....class H with SMPS is popular too,... but not so much like class D

to find PRO AUDIO quasicomlementary nmos output stage (AB or H class) is really impossibile often amplifiers use BJT because this devices much more cheaper to produce amplifier,
 
Last edited:
yes this Amplifier exist, have working some years ago for this company and sold a lot of pcs. from this model to european PA clients,

but heavy analaog amplifier is since 3 years obsolet in market by european clients.... and my previous factory dont have since today SMPS, this model dont like continous maximum Subbass output power, output devices can failed.

I dont like BJTs in output stage against bad experience, often different BJT amps failed with continous high output power

with hundreds of Class D and 50 pcs. sample NMOS amps +/- 100 V Rail no known problems compare to BJTs amps

very popular is class D in market.....class H with SMPS is popular too,... but not so much like class D

to find PRO AUDIO quasicomlementary nmos output stage (AB or H class) is really impossibile often amplifiers use BJT because this devices much more cheaper to produce amplifier,
Development amplifier from zero is difficult, I suggest to use reable solution from brands, I am not sure that the prise is a reason to not use that topology by brands.
Regards