500W PA amplifier with Limiter

[apexaudio]

Hi Apex..I just finish built P500 from P900 without step-up driver..and with jumper as yours intructions..
Testing with toroid ct 47vac, elco Philips 17.000uf/100vdc x 2, and dioda bridge 40A...
Result..on tone control positioning 9 o'clock..sound (low, mid, high) is clear, detail, beautiful...but on positioning 10 o'clock..low unstable...What is wrong??
Sorry my english
Regards

Can you post picture, I must see GND wireing, do you measurment DC voltages, do you have osciloscope?
Regards

 

[electra_ina]

Thanks Apex...After I check again..one ground from input unconnected...so I connected from central ground...PA will OK...sound of wonderfull..low, mid, high...all is OK..One again thanks Apex..DC offset 100mv. I haven't osciloscop. This picture:
Imageshack - moduldepan.jpg
Imageshack - modulbawahjauh.jpg
Imageshack - tampaklengkap.jpg

 

[apexaudio]

Thanks Apex...After I check again..one ground from input unconnected...so I connected from central ground...PA will OK...sound of wonderfull..low, mid, high...all is OK..One again thanks Apex..DC offset 100mv. I haven't osciloscop. This picture:
Imageshack - moduldepan.jpg
Imageshack - modulbawahjauh.jpg
Imageshack - tampaklengkap.jpg

Do you have 0,5V on 100R in emiters MJE340/MJE350? You can have lower offset if you matching 2N5551/2N5401, and MJE340/MJE350, this is better than adjust by trimpot and go to unsimetry.
Regards

 

[electra_ina]

Ups...sorry Apex..I mean DC offset is 9,8mv not 100mv. This picture:
[IMG=http://img443.imageshack.us/img443/8409/dcoffset.th.jpg][/IMG]
Uploaded with ImageShack.us
Regards

 

[apexaudio]

Ups...sorry Apex..I mean DC offset is 9,8mv not 100mv. This picture:
[IMG=http://img443.imageshack.us/img443/8409/dcoffset.th.jpg][/IMG]
Uploaded with ImageShack.us

Regards

OK, that's better,
Regards

 

[electra_ina]

Thanks...now I will try to add step up driver with TL072...become to PA900..May be today (start my local time is Sunday 6.11AM) I can finish this project...
Regards

 

[apexaudio]

Thanks...now I will try to add step up driver with TL072...become to PA900..May be today (start my local time is Sunday 6.11AM) I can finish this project...
Regards

What is power you have with B500? Is this heatsink large enough?

 

[electra_ina]

Absolutly..I will built P900, but very hard to find IR2117, so I test this as P500. Result is Ok. Btw..with step up driver TL072 I will do to P900. My heatshink is anodized 11mm x 28 mm x 4 mm. Is this enough for P900 single channel???
Regards

 

[AndrewT]

My heatsink is anodized 11mm x 28 mm x 4 mm

I hope you mean cm! and even that seems a bit small.
Or are these dims in inches?

 

[apexaudio]

He mean cm, heatsink is small, but with two fans for cooling, amp will work.

 

[electra_ina]

I'm sorry...yes I mean "cm" not mm. Thanks Andrew and Apex...

 

[apexaudio]

How hot is heatsink now without fan cooling?

 

[electra_ina]

With PSU +/-70Vdc (CT 47vac) and volume Tone Control (TC) on 10 o'clock, I still can touch heatshink..not so hot...Btw..TR final I used 2SA1215B-2SC6011B with Vcbo=260V, Ic=15A, and Pc=160W.
Regards

 

[eesbiboi]

Thanks Apex...After I check again..one ground from input unconnected...so I connected from central ground...PA will OK...sound of wonderfull..low, mid, high...all is OK..One again thanks Apex..DC offset 100mv. I haven't osciloscop. This picture:
Imageshack - moduldepan.jpg
Imageshack - modulbawahjauh.jpg
Imageshack - tampaklengkap.jpg

are those blue resistors rated 1/4w or 1/2w???tnx

 

[electra_ina]

are those blue resistors rated 1/4w or 1/2w???tnx

It's 1/2w. I have stock 1/2w resistor and I applied it.
Regards

 

[engel dela pena]

With PSU +/-70Vdc (CT 47vac) and volume Tone Control (TC) on 10 o'clock, I still can touch heatshink..not so hot...Btw..TR final I used 2SA1215B-2SC6011B with Vcbo=260V, Ic=15A, and Pc=160W.
Regards

can you share your tone control ckt & pcb

 

[fpaul]

can you share your tone control ckt & pcb

I'm wondering about the tone contol too; I haven't seen one in schematics. I don't need one but don't want to miss a connection if required.

Started building my boards but now have to order some more parts.

 

[apexaudio]

I'm wondering about the tone contol too; I haven't seen one in schematics. I don't need one but don't want to miss a connection if required.

Started building my boards but now have to order some more parts.

Amplifier don't have any tone controls, just have pot for volume control.
If you want to use mic preamp with tone control, equaliser or active x-over for sub-sut operate, that is separate modul, I can share some of this circuits in new thread "Active x-overs" if you want.
Regards

 

[Gitsa]

I finished collecting b500, here's what I got! "A few days ago will be tested.

 

[nigelwright7557]

I finished collecting b500, here's what I got! "A few days ago will be tested.

Putting the high power resistors so close is bad design.
They need to have air all around them to dissipate the heat.