thank a lot!
1vac=1.2vrms ? is it always working formula?
i need psu with 55vac*2 ? for npn-pnp transistors scheme... +55 to pnp and -55to npn?
so if u=55, why on the original scheme b500 written +-90Vmax ?
and why we double amperes for 2 chanels (11*2) but dont double voltage ?
1vac=1.2vrms ? is it always working formula?
i need psu with 55vac*2 ? for npn-pnp transistors scheme... +55 to pnp and -55to npn?
so if u=55, why on the original scheme b500 written +-90Vmax ?
and why we double amperes for 2 chanels (11*2) but dont double voltage ?
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Ppsu=25A*55vac=1375VA
but apexaudio said he use 1000va transformer for this amp, and somebody here use even less VA psu...
as I understood we can use less VA psu but then we have upper our voltage,what is algorythm here ?
sorry for too much quiestions...the problem is to get 1000-1500va trans here..it is very expensive..so am wondering if its possible to use less VA trans and just upper the voltage of trans...but i cannot understand algirythm of uppering the voltage
for example, how much voltage I need for 700VA trans to get 1000wt on stereo, or its not possible?
why apexaudio on original scheme wrote Vmax=+-90V..not+-55 as we calculated ?!
but apexaudio said he use 1000va transformer for this amp, and somebody here use even less VA psu...
as I understood we can use less VA psu but then we have upper our voltage,what is algorythm here ?
sorry for too much quiestions...the problem is to get 1000-1500va trans here..it is very expensive..so am wondering if its possible to use less VA trans and just upper the voltage of trans...but i cannot understand algirythm of uppering the voltage
for example, how much voltage I need for 700VA trans to get 1000wt on stereo, or its not possible?
why apexaudio on original scheme wrote Vmax=+-90V..not+-55 as we calculated ?!
do u mean 55vac=80vdc? the voltage goes up after capacitors in PSU ? by which formula you calculated it?
what means ct? ct=0,ct=ground,ct=?)
by the way all comes more clear for me, thank you Brothers )
ps still I cannot understand, why apexaudio use 1000va trans and its ok, the formula said it should be 1375va (25A*55vac)
what means ct? ct=0,ct=ground,ct=?)
by the way all comes more clear for me, thank you Brothers )
ps still I cannot understand, why apexaudio use 1000va trans and its ok, the formula said it should be 1375va (25A*55vac)
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thank you !
also I have to understand how to take voltage on 2 chanels from 1 transformer.
so I have on secondary 3 taps, first +55, second CT, third -55 , right?
+55 I give to one part of transistors in one chanel, -55 i give to another part of transistores in the same chanel....
and from where I shoud take voltage to second chanel ? from the same pots that I used for first chanel?
also I have to understand how to take voltage on 2 chanels from 1 transformer.
so I have on secondary 3 taps, first +55, second CT, third -55 , right?
+55 I give to one part of transistors in one chanel, -55 i give to another part of transistores in the same chanel....
and from where I shoud take voltage to second chanel ? from the same pots that I used for first chanel?
secondary 55vac,ct,55ac after rectified with smoothing capacitors, u will get +75vdc ct -75 or +80vdc, ct,-80vdc.
if ur transformer 1000va or watts +75 goes to positive side of the amp -75vdc goes negative side of the amp, and ct is gnd,
use 8,10000uf /100v caps for psu, give psu positve to two channels, negative to two chanels. and the gnd also for two channels.
if ur transformer 1000va or watts +75 goes to positive side of the amp -75vdc goes negative side of the amp, and ct is gnd,
use 8,10000uf /100v caps for psu, give psu positve to two channels, negative to two chanels. and the gnd also for two channels.
how if 500 standard given 2 Ohm load, is there a need to change the value of its components?
thanks
you need to tell the supplier/manufacturer:
Input voltage
Output voltage
Number of secondary windings
Regulation
VA
eg.
230:40+40Vac dual secondary. 1000VA, 3 to 4% regulation.
That's all.
You don't need to know the current rating, you don't need to tell them the current rating.
You ask why?
Because you are not using the transformer to feed AC to a resistor load.
And that 1000VA will satisfactorily power a 500W to 1000W amplifier or set of amplifiers with a total maximum output of 500W to 1000W.
You are feeding the output to a capacitor input filter. The current rating goes out the window when a non resistor load is used.
Input voltage
Output voltage
Number of secondary windings
Regulation
VA
eg.
230:40+40Vac dual secondary. 1000VA, 3 to 4% regulation.
That's all.
You don't need to know the current rating, you don't need to tell them the current rating.
You ask why?
Because you are not using the transformer to feed AC to a resistor load.
And that 1000VA will satisfactorily power a 500W to 1000W amplifier or set of amplifiers with a total maximum output of 500W to 1000W.
You are feeding the output to a capacitor input filter. The current rating goes out the window when a non resistor load is used.
I understood it, but anyway.. I sended my psu info allready to 3 manufacturers and all of them ask me what current have to be at secondary...if I tell them 25A, they said it will be 2*55V*25A=2750VA transformer!!!
please, help why like this....
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and if I dont tell to them any current, they write this spec for ready psu:
1350 VA, 50Hz 220В
1: +55В under load 12,3А
2: -55В under load 12,3А
(D*d*H) - 186*47*78 мм
9,92 kg
or
1000 VA, 220v, 50Hz
1: +55В under load 9,1А
2: -55В under load 9,1А
(D*d*H) - 184*52*74 мм
9,11 kg
but 9,1A or 12.3A dont enough for 2 chanels stereo , am I right?!
1350 VA, 50Hz 220В
1: +55В under load 12,3А
2: -55В under load 12,3А
(D*d*H) - 186*47*78 мм
9,92 kg
or
1000 VA, 220v, 50Hz
1: +55В under load 9,1А
2: -55В under load 9,1А
(D*d*H) - 184*52*74 мм
9,11 kg
but 9,1A or 12.3A dont enough for 2 chanels stereo , am I right?!
I'm sorry about stupid quiestion, they write it for R load of course...
so, Iam ordering this one
1000 VA, 220v, 50Hz
1: +55В under load 9,1А
2: -55В under load 9,1А
(D*d*H) - 184*52*74 мм
9,11 kg
hope everything is clear now to start the amp building
and big thanks to all DIY users for help
so, Iam ordering this one
1000 VA, 220v, 50Hz
1: +55В under load 9,1А
2: -55В under load 9,1А
(D*d*H) - 184*52*74 мм
9,11 kg
hope everything is clear now to start the amp building
and big thanks to all DIY users for help
they request current ratings for all secondary windings because not all secondary windings must have the same power ratings. in case of 1000VA transformer,they don´t know if you need 700VA from one 55Vac secondary,100VA from other 55Vac secondary,190VA from one 18Vac secondary and 10VA from one remaining 18Vac secondary/or you need 950VA from both 55Vac secondaries to power amp and 50VA to power other circuites in amp other than output stages. not all the secondary windings must have the same power ratings,but they all together should have power equall to a primary winding/total transformer power.
If you are building 2 B500 chanels,i would use at least 1500VA transformer.
If you are building 2 B500 chanels,i would use at least 1500VA transformer.
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