500W PA amplifier with Limiter

[fpaul]

Would a couple of these transformers work, using one per channel?

Basler 16-16431

120V input Marked at 300 Watt checked out as 500W
Output Dual 52V, Dual 10V, 20V, and 6.3V taps

 

[apexaudio]

Would a couple of these transformers work, using one per channel?

Basler 16-16431

120V input Marked at 300 Watt checked out as 500W
Output Dual 52V, Dual 10V, 20V, and 6.3V taps

Yes it would.

 

[fpaul]

Hmm, I guess I have to build this then. Not sure if that is good or bad. I built a copy of a 50 watt Marshall tube guitar amp and about 30 guitar pedals but not sure if that qualifies me for this. Learned alot but still somewhat painting by numbers. Not going to let that stop me from trying though and I really need a good pa to finish my rig. Hoping I can get some answers for a few stupid questions when they come up. Alot has already been answered though. Thanks for sharing the project. Take awhile to get the parts and burn the boards...

 

[apexaudio]

Hmm, I guess I have to build this then. Not sure if that is good or bad. I built a copy of a 50 watt Marshall tube guitar amp and about 30 guitar pedals but not sure if that qualifies me for this. Learned alot but still somewhat painting by numbers. Not going to let that stop me from trying though and I really need a good pa to finish my rig. Hoping I can get some answers for a few stupid questions when they come up. Alot has already been answered though. Thanks for sharing the project. Take awhile to get the parts and burn the boards...

With basic expirience in diy, you have no problem to build this amplifier. I made B500 to be simple and easy for diy, no matching no adjust, just few measurment with DMM.
Regards

 

[RocketTeam]

Hello,

I'm from Thailand. My experience level of audio circuit is novice.
I will DIY this project soon. But I'm not sure how can I found the LED-LDR module in local market.

Any problem occure if I not install it?

Thank you for sharing the project.

Sorry for my poor English.

Regards,

 

[apexaudio]

Hello,

I'm from Thailand. My experience level of audio circuit is novice.
I will DIY this project soon. But I'm not sure how can I found the LED-LDR module in local market.

Any problem occure if I not install it?

Thank you for sharing the project.

Sorry for my poor English.

Regards,

No problem, you just have no clip limiter, and you can put regular LED for clip indicator.
Regards

 

[fpaul]

For a two channel amp, using two transformers, I need 2 main boards, 2 PSU boards, and 2 protect boards, is this correct? Could someone please confirm this? Making boards isn't my favorite thing so I want to be sure I need them all.

 

[apexaudio]

For a two channel amp, using two transformers, I need 2 main boards, 2 PSU boards, and 2 protect boards, is this correct? Could someone please confirm this? Making boards isn't my favorite thing so I want to be sure I need them all.

Yes, you nee this pcbs X2, but pcbs are smal.
Regards

 

[engel dela pena]

You ca use H900 as B500, just put jumper D-S on place fets, and use only HV rails.

h900 is my 1st pcb
since ir2117 is not available
i will still use my pcb for b500
too lucky only few modification need to be done
i just compare h900 & b500
then copy b500 traces
maybe several jumpers will do

 

[apexaudio]

h900 is my 1st pcb
since ir2117 is not available
i will still use my pcb for b500
too lucky only few modification need to be done

SFA1603 must be jumpered also,
Regards

 

[engel dela pena]

apex,
please post b500 component landscape with traces shadow like this h900 please

 

[apexaudio]

apex,
please post b500 component landscape with traces shadow like this h900 please

See post #8
Regards

 

[engel dela pena]

thanks

 

[apexaudio]

thanks

What is rail voltage on your PSU?

 

[engel dela pena]

What is rail voltage on your PSU?

+/-70VDC
is this safety margin voltage for B500?

 

[apexaudio]

+/-70VDC
is this safety margin voltage for B500?

Yes, +/-90VDC is maximum rail voltage.

 

[fpaul]

use 4x 10000uF/100V snap-in caps

Man, these aren't cheap. Looks like I'm making a one channel amp now and adding the other channel later. Well, that's why I like DIY anyway. Several small purchases over time are less painful than one big one.

 

[fpaul]

Is the component labeled 12V 16A in the soft start a dpst relay? Also, where does the +/- 30vdc come from? It looks like no power from the mains until the 30vdc comes in. Sorry if this is a stupid question; I've never had to build this type circuit until now. Is this circuit absolutely necessary? Thanks for any help. I'll be etching boards this weekend.

 

[apexaudio]

Is the component labeled 12V 16A in the soft start a dpst relay? Also, where does the +/- 30vdc come from? It looks like no power from the mains until the 30vdc comes in. Sorry if this is a stupid question; I've never had to build this type circuit until now. Is this circuit absolutely necessary? Thanks for any help. I'll be etching boards this weekend.

30VDC for soft-start relay you have from protect board useing +/-15V without GND. Without soft-start main fuse will blow when transformer powered up. QSC use 1R 10W NTC on some amps instead soft-start circuit.
Regards

 

[electra_ina]

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