500W PA amplifier with Limiter

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electra_ina

electra_ina

Member
Joined 2009
sakis said:
nice work ...clean .... only a couple of things ...

transformer looks kinda small and also the heatsink of the predriver (s) will be better if screwd somewhere since constan transportation will make this fail .... and especially if its ment to be for PA use
Click to expand...

Thanks Sakis....
Yes I agree transformer too small only 10A CT47Vac...but only this I have...In my place..too hard to find good toroid with big ampere (power). In the electronic shop alot of sale toroid from China ...I thinks not so good...Any way..in some electronic shop ready EL transfrmer with bigger body..not enough for 2U box...

Please info: can I placed TR predriver on main HS? What happen if I do it??
Sorry my english...;)
Regards
 
R

Rafael S. M.

Member
Joined 2010
Well, now no more doubt, I will now buy the components, with you say, it is not better than crown or crest, but it comes close, huh?

i can separate the PCB into two parts? one with only the power transistors and emitter resistors, and the other with the rest, but the driver and MJE340 MJE will be in the same sink of power, like to separate to make it easier to make the PCB and mount to the chassis between them the maximum distance is only 2 or 3 inches

last question, promise not to tell anything more! hhehehe
I can put on each base of the transistors of an output resistor of low value, at 4.7 R, the current split is better ok? .. it helps, hinders, or changes nothing about this amp?
 
apexaudio

apexaudio

Member
Joined 2010
Rafael S. M. said:
Well, now no more doubt, I will now buy the components, with you say, it is not better than crown or crest, but it comes close, huh?

i can separate the PCB into two parts? one with only the power transistors and emitter resistors, and the other with the rest, but the driver and MJE340 MJE will be in the same sink of power, like to separate to make it easier to make the PCB and mount to the chassis between them the maximum distance is only 2 or 3 inches

last question, promise not to tell anything more! hhehehe
I can put on each base of the transistors of an output resistor of low value, at 4.7 R, the current split is better ok? .. it helps, hinders, or changes nothing about this amp?
Click to expand...
Best thing in DIY is that you can do anything what you want, you have no response to anybody exsept yourself.
Regards
 
eesbiboi

eesbiboi

Member
Joined 2010
nao to pico convertion

apex,
sir can you please help me with converting this nanofarad caps to picofarad???...
we are trying to build your 500w pa amp...but nanofarad is not available in our place...would ceramic caps do the job or mylar ones???...
100nf = pF?...
47nF = pF?...
10nF= pF?...
tnx...
 
smartx21

smartx21

Member
Joined 2010
eesbiboi said:
apex,
sir can you please help me with converting this nanofarad caps to picofarad???...
we are trying to build your 500w pa amp...but nanofarad is not available in our place...would ceramic caps do the job or mylar ones???...
100nf = pF?...
47nF = pF?...
10nF= pF?...
tnx...
Click to expand...

nF was formerly known as kpF, that is, 1nF=1kpF=1000pF.
So, 100nF means 100kpF, or 100 000pF;
47nF means 47kpF, or 47 000pF;
10nF means 10kpF, or 10 000pF.
Regards,
Max.
 
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