500W PA amplifier with Limiter

[apexaudio]

Hi! Mile

The HF instability problem was solved i dont know how it was happen

but need to increase treble response its not even like ax-14

please help me mile

Regards
Joel

Use preamp with tone control like http://www.diyaudio.com/forums/analog-line-level/167363-mic-line-eq-preamps.html
Regards

 

[wattaniya]

hi apex sir,
my b500 is working perfect without chassis, but i put hole gadgets inside the chassis and now big hum is coming through speakers, what is the reason for this?

 

[apexaudio]

hi apex sir,
my b500 is working perfect without chassis, but i put hole gadgets inside the chassis and now big hum is coming through speakers, what is the reason for this?

Did you connect GND to chassis and in what point?

 

[wattaniya]

Did you connect GND to chassis and in what point?

i connect GND to near the power transformer.

 

[wattaniya]

B500 TRIPLE DARLINTON,
neet to put 10k pot and 47r base to emmitter to drivers.

pcb size 70mm by 230mm.

 

[apexaudio]

i connect GND to near the power transformer.

Connect GND near to the input terminals (post #54)

 

[wattaniya]

For BIAS setup R22 should be 1k2 instead 680R for triple darlington output stage, and R23 is correct 330 ohms.
Q5 (MJE340) must be on main heatsink with outputs.
Predrivers MJE340/350 can use smal heatsinks, but no need.
Regards

hi apex sir,
is this r22, r23 value correct for triple darlington.

in h900 thread u said post no 2060 image value is correct, both values are different values, pls verify this.

only I'm 100percent success with Ur amps,

 

[nix]

B500 TRIPLE DARLINTON,
neet to put 10k pot and 47r base to emmitter to drivers.

pcb size 70mm by 230mm.

hi nazirdigi
do you have pcb copper side of this layout?

regards
nix

 

[kamranyousaf]

yes, you have a gain of x45, a 1volt input should drive your amp to almost clipping.

Sir,

I think pre amps can solve your problem effectively...🙂

 

[kamranyousaf]

Hi! Mile
I tried compensating with 47pF caps but didn't worked still the zobel resistor is getting warm

if amplifier is used continuously that is oscillating then are there any possibilities of weakening of output transistors that leads to poor sound quality and power??

Sir,

If u r using the thinner wire in zubel then it will also occur.🙁

 

[wattaniya]

HI APEX SIR ,
pls verify this gnd wiring.

with full volume, no input signal provided, the hum is coming through speakers , what is the solution?

i checked some professional amplifiers with full volume without input signal and no hum coming through speakers.

 

[AndrewT]

wrong.
the signal grounds must go back to the main audio ground. The safety Earth is quite different.

 

[apexaudio]

HI APEX SIR ,
pls verify this gnd wiring.

with full volume, no input signal provided, the hum is coming through speakers , what is the solution?

i checked some professional amplifiers with full volume without input signal and no hum coming through speakers.

Connect wire from PSU GND to the input terminals, and from input terminals to the chassis

 

[wattaniya]

thanks andrewt,
which is main audio GND? (psu gnd or chassis gnd)?

 

[wattaniya]

Connect wire from PSU GND to the input terminals, and from input terminals to the chassis

thanks for the reply.
my input terminals negative metal is already touching to the chassis.

 

[apexaudio]

thanks for the reply.
my input terminals negative metal is already touching to the chassis.

Ok, just connect wire from PSU GND to the input terminals, you can connect 100nF/400V from PSU GND to the chassis but only connect from GND to the chassis must be on input terminals.

 

[wattaniya]

i cant understand,
which is correct?
1-100nf/400v gnd to chassis.
2-gnd to input terminals negative.
3-gnd to chassis.

 

[wattaniya]

B500 TEF ROUTING PCB FINISHED.
starting to make the pcb with silkscreen.

 

[wattaniya]

hi apex sir,
i did what u said in post 2016, now no hum.

my camera focusing is little problem, that's why the images are smudge.
i used these tools to make the casing, taper,taper hande,mini circular saw,drill machine, jigsaw mashine,c clamp.
thanks.

 

[apexaudio]

hi apex sir,
i did what u said in post 2016, now no hum.

my camera focusing is little problem, that's why the images are smudge.
i used these tools to make the casing, taper,taper hande,mini circular saw,drill machine, jigsaw mashine,c clamp.
thanks.

Thanks for the pictures, what about sound?
Regards