400W RMS at 35V , it is posible ??

darkm4n · 15th April 2005, 11:40 PM

Hi,

Recently i saw at a locat electronic dealer some audio kit's that can deliver 400W RMS at 8 ohm and 450W RMS at 4 ohm useing only 35V ( Maxim ) ... HOW THIS IS POSIBLE ?!?! Only 35 V for 400W ??

There are the schematic and some descreption , sorry but the pages are in romanian ....

http://www.adelaida.ro/adelaida/cata...s/AD_020V9.pdf

I'am very interested if that people lie .. i personaly don't think they can produce 400w out of 35V ..

THANKS !!
Mihai .

pinkmouse · 15th April 2005, 11:48 PM

Are they bridged?

sek · 16th April 2005, 12:47 AM

The data sheet states an output current (Io on page 2) of typically 9A at +-35V in order to reach 400Watts minimum!

Four lines further down the page they state Imax of 8A at +-30V... that's making the rest of the specifications valid for only about 200W output power, half of what was initially advertised

Together with the recommendation of a 400VA trafo for a 400W amplifier power ... you can gather your own opinion about it.

My opinion: not a terribly bad circuit, but too complex for the power and distortion specs (it's pretty outdated technology).
Thus, it solely depends on the price you can get it for (perhaps you can make a listening test, first?).

Sebastian.

darkm4n · 16th April 2005, 06:58 AM

So .. it's not posible ..

I phoned them and told me that their kit's reach about 380W RMS...

)

Enzo · 16th April 2005, 09:12 AM

Look at the schematic. Each terminal of the speaker is driven by its own push pull output stage. The speaker is not connected to ground or common. The two power stages operate out of phase, so when one is being driven positive, the other is going negative. This is called bridging the amps.

Your 35 volt rail by itself can't generate the power specified, but when one side goes to +35 and the other side goes to -35, then there is 70volts across the speaker. In practice, it never goes all the way to the rail voltage, so we back off the specs a bit for that.

That is how they plan to get that level of power from those supply rails.

darkm4n · 16th April 2005, 09:27 AM

So .. it's posible

THANSK !!!!

bigbulb · 16th April 2005, 09:36 AM

Looking at the attached schematic, it is bridged class B amplifier. the maximum power for 35V+- in 8 ohm will only give you around 220W-240W (clipping!) and that is assume that the schematic is nearly ideal, with efficientcy of around 80% ( can calss B amplifier do that efficiency in bridged mode? I think only class D can do that.)

edl · 16th April 2005, 02:50 PM

a 400W/8ohm bridged amp means two 200W/4ohm amp.
for 200W/4ohm, if you are using a 10000uF puffer, and a 300VA rafo, you'll need 56V. if you are correct.
if tehere were no losts, and the psu would be very-very stabilized, you would need +/-40V!
so that kit is a joke.
oh, yeah, I almost forgot it: 400W from 4 output devices? may be, for 30 secs, with 1KHz input...
(in my whole text i was talking about RMS powers)

15th April 2005, 11:40 PM	#1
darkm4n diyAudio Member Join Date: Aug 2003 Location: Bucharest	400W RMS at 35V , it is posible ?? Hi, Recently i saw at a locat electronic dealer some audio kit's that can deliver 400W RMS at 8 ohm and 450W RMS at 4 ohm useing only 35V ( Maxim ) ... HOW THIS IS POSIBLE ?!?! Only 35 V for 400W ?? There are the schematic and some descreption , sorry but the pages are in romanian .... http://www.adelaida.ro/adelaida/cata...s/AD_020V9.pdf I'am very interested if that people lie .. i personaly don't think they can produce 400w out of 35V .. THANKS !! Mihai .

15th April 2005, 11:48 PM	#2
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Are they bridged? __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

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16th April 2005, 12:47 AM	#3
sek diyAudio Member Join Date: May 2003 Location: Berlin	The data sheet states an output current (Io on page 2) of typically 9A at +-35V in order to reach 400Watts minimum! Four lines further down the page they state Imax of 8A at +-30V... that's making the rest of the specifications valid for only about 200W output power, half of what was initially advertised Together with the recommendation of a 400VA trafo for a 400W amplifier power ... you can gather your own opinion about it. My opinion: not a terribly bad circuit, but too complex for the power and distortion specs (it's pretty outdated technology). Thus, it solely depends on the price you can get it for (perhaps you can make a listening test, first?). Sebastian.

16th April 2005, 06:58 AM	#4
darkm4n diyAudio Member Join Date: Aug 2003 Location: Bucharest	So .. it's not posible .. I phoned them and told me that their kit's reach about 380W RMS... )

16th April 2005, 09:12 AM	#5
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	Look at the schematic. Each terminal of the speaker is driven by its own push pull output stage. The speaker is not connected to ground or common. The two power stages operate out of phase, so when one is being driven positive, the other is going negative. This is called bridging the amps. Your 35 volt rail by itself can't generate the power specified, but when one side goes to +35 and the other side goes to -35, then there is 70volts across the speaker. In practice, it never goes all the way to the rail voltage, so we back off the specs a bit for that. That is how they plan to get that level of power from those supply rails.

16th April 2005, 09:27 AM	#6
darkm4n diyAudio Member Join Date: Aug 2003 Location: Bucharest	So .. it's posible THANSK !!!!

16th April 2005, 09:36 AM	#7
bigbulb diyAudio Member Join Date: Aug 2004 Location: klamazoo	Looking at the attached schematic, it is bridged class B amplifier. the maximum power for 35V+- in 8 ohm will only give you around 220W-240W (clipping!) and that is assume that the schematic is nearly ideal, with efficientcy of around 80% ( can calss B amplifier do that efficiency in bridged mode? I think only class D can do that.)

16th April 2005, 02:50 PM	#8
edl diyAudio Member Join Date: Oct 2004	a 400W/8ohm bridged amp means two 200W/4ohm amp. for 200W/4ohm, if you are using a 10000uF puffer, and a 300VA rafo, you'll need 56V. if you are correct. if tehere were no losts, and the psu would be very-very stabilized, you would need +/-40V! so that kit is a joke. oh, yeah, I almost forgot it: 400W from 4 output devices? may be, for 30 secs, with 1KHz input... (in my whole text i was talking about RMS powers)

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