Good afternoon guys I must say this is the best thread for a while I have been grinning from the first couple of posts right until the last.
Merry Christmas everybody and keep up the entertainment!!
Merry Christmas everybody and keep up the entertainment!!
1+1=2
Marry Christmas to all of you guys
Never mind
Im just saying that speaker is not a heating element ohm's law is correct but speaker impedance is changing while speaker is working
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Netiks,
These simple formulas are the basis for calculations:
P(power)=I(current)*V(voltage)=R*I^2=V^2 /R(resistance)
To get 800VA RMS with 8 ohm you need 80V RMS output signal at 10A or +/-113.2V peak to peak. Now, there are loses on the way. On your bridges you will loose over 1V, transformer loses (if you use a huge one these may be minimized), transistor loses - for bjts you can add up to 6V per rail, for power mosfets you have to add about 7% on top of it. So to deliver 800VA RMS output to your nominal 8 ohm speaker (don't forget that at some frequencies it may drop at least to 6 ohms) you need +/-120V PS with bjts. With normal loses of 20% (rule of a thumb) you need 120V*12A = 1.5kW toroid with about 2 * 86V secondaries. But all that will be waste of time and money as the suggested Toshibas have Vce of 230V.
If you reduced your hunger for power and voltage you will see that at +/-100V PS these Toshibas can deliver only 100mA for 100ms (SOA graph). With 10 pairs you will get 1A while you need 10A. And all that provided that you will keep them cool at 25dg C.
If you want a powerful amp start with examining SOA of power transistors. For high power amps Toshibas or OnSemis are no good. If you like bjts then go for mg6331/9411(r). These at least can deliver about 2A at +/-100V for 100ms at 25dg C. Optimum power/voltage combination for these will probably be about +/-70 to 75V. Do you maths and find out.
Merry Christmas
cheers,
These simple formulas are the basis for calculations:
P(power)=I(current)*V(voltage)=R*I^2=V^2 /R(resistance)
To get 800VA RMS with 8 ohm you need 80V RMS output signal at 10A or +/-113.2V peak to peak. Now, there are loses on the way. On your bridges you will loose over 1V, transformer loses (if you use a huge one these may be minimized), transistor loses - for bjts you can add up to 6V per rail, for power mosfets you have to add about 7% on top of it. So to deliver 800VA RMS output to your nominal 8 ohm speaker (don't forget that at some frequencies it may drop at least to 6 ohms) you need +/-120V PS with bjts. With normal loses of 20% (rule of a thumb) you need 120V*12A = 1.5kW toroid with about 2 * 86V secondaries. But all that will be waste of time and money as the suggested Toshibas have Vce of 230V.
If you reduced your hunger for power and voltage you will see that at +/-100V PS these Toshibas can deliver only 100mA for 100ms (SOA graph). With 10 pairs you will get 1A while you need 10A. And all that provided that you will keep them cool at 25dg C.
If you want a powerful amp start with examining SOA of power transistors. For high power amps Toshibas or OnSemis are no good. If you like bjts then go for mg6331/9411(r). These at least can deliver about 2A at +/-100V for 100ms at 25dg C. Optimum power/voltage combination for these will probably be about +/-70 to 75V. Do you maths and find out.
Merry Christmas
cheers,
I found this from elektor titan 2000
(Supply voltage = ±70 V; quiescent current = 200–400 mA)
Input sensitivity 1.1 V r.m.s.
Input impedance 47.5 kΩ
Sine-wave power output (0.1% THD) 280 W into 8 Ω; 500 W into 4 Ω; 800 W into 2 Ω
So most amplifier DIY designs have fake power rating because they claim that You can get 1000w rms from +/-100volts or even 800w rms from +/-900w
Why would they lie
(Supply voltage = ±70 V; quiescent current = 200–400 mA)
Input sensitivity 1.1 V r.m.s.
Input impedance 47.5 kΩ
Sine-wave power output (0.1% THD) 280 W into 8 Ω; 500 W into 4 Ω; 800 W into 2 Ω
So most amplifier DIY designs have fake power rating because they claim that You can get 1000w rms from +/-100volts or even 800w rms from +/-900w
Why would they lie
Thank You My friend for good explanation
So I wil need to add more windings on my transformers to get more voltage and need to find amplifier driver that can drive on +-110volts to get 800real rms power the real question is how much voltage can withstand 2sc5200/2sa1943? on rails
Merry Christmas to You too
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What driver circuit to use on BJT for 800rms 8ohm and 1000rms 8ohm?
What other transistor pairs I can Use instead toshibas 2sa5200/2sa1943
mg6331/9411
Regards
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A lot of amplifier designs on this internet with fake power ratings
But I was right at some points
Merry Christmas
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1000W into speaker requires approximately 5000W of BJT output device in a ClassAB amplifier.
MJ21193/4 @ 250W would be 10pr output stage to meet that 1000W target.
Most will go switching to avoid the device count and the enormous heatsinks.
The switching could be digital, or ClassG, or ClassH. You choose which you can design.
MJ21193/4 @ 250W would be 10pr output stage to meet that 1000W target.
Most will go switching to avoid the device count and the enormous heatsinks.
The switching could be digital, or ClassG, or ClassH. You choose which you can design.
But I can make 4x600w 8ohm amps 4 channel amplifier and for 2x 1200rms at 8 ohms I can bridge 😀 with toshibas 2sc5200/2sa1943
There is a cheaper way than making one amp on 1200rms 8ohms
BJT's are too expensive
regards
two of these bridged amps
There is a cheaper way than making one amp on 1200rms 8ohms
BJT's are too expensive
regards
two of these bridged amps
Attachments
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I just checked farnell.com mg6331 is 2.72euros I taught that its more expensive
Can I just put BJT's instead toshibas 2sc5200/1943 on the same driver circuit or no?
But in my country I checked electronic stores no mg6331 they dont have them
Can I just put BJT's instead toshibas 2sc5200/1943 on the same driver circuit or no?
But in my country I checked electronic stores no mg6331 they dont have them
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