Simple schema

bracoraab · 10th May 2007, 10:51 AM

I found this simple schema on the net, the opa552 can supply wiyh +- 30V and the power mosfet I think could be IRFP240 and IRFP9240?
How many watts I can get with 35 V per rail? Is this a poor quality circuit?

Cheers
Braco

sparkle · 10th May 2007, 11:24 AM

Braco - +/-35V will give you arround 50-55W/8ohm.....

regarding quality of the amp - it is hard to say if it is good or bad - because all of us have a different taste of the music and also different speakers - one amplifier is not going to work at its best on one speaker or another different type of the speaker....so the best is to try it.... it can certainly be better made - with some improvements in this basic circuitry - but also you may like it how it sounds the way it is........
regards
daniel

bracoraab · 10th May 2007, 11:29 AM

Thanks a lot Daniel

sparkle · 10th May 2007, 11:33 AM

no problem - there is a lot other sch on the net that fit under 50-55W ......for example DX amp - that is a nice very good quality amp, also you have Project 101 from Rod Elliot that can be fitted inside 50W....

enjoy

sixtek · 10th May 2007, 12:26 PM

Hi,

Max. PSU voltage is +/-30V for the OPA. Then I would use +/-25V supply rails.
Calculating with 5V losses (that will be more: few Volts on supply caps, 1-2V on diode bridge, and few Volts in the mosfet) the output power will be 25W-RMS on 8Ohm and 50W-RMS on 4Ohm.
So it's a 30W amp.

sparkle · 10th May 2007, 12:39 PM

sixtek - you are right - i missed that - i was to quick

did not check for the voltage - no time ...

sixtek · 10th May 2007, 01:01 PM

No matter my friend

darkfenriz · 10th May 2007, 01:18 PM

Is it designed by Dariusz Kulesza aka. Drakul ?

cs · 10th May 2007, 02:18 PM

Quote:

Originally posted by bracoraab
I found this simple schema on the net, the opa552 can supply wiyh +- 30V and the power mosfet I think could be IRFP240 and IRFP9240?
How many watts I can get with 35 V per rail? Is this a poor quality circuit?

Cheers
Braco

Also, don't forget the OPA445, which will run off +/-45V rails, so you can get approaching 100W.

I have been looking at just such an amp recently, using the OPA445 + BUZ901/5 mosfets. Simulated performance looks good, when configured for a closed-loop gain of 2 (6dB). I will then use a driver op amp run from from +/-24V to provide the rest of the gain required.

sparkle · 10th May 2007, 07:44 PM

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10th May 2007, 11:24 AM	#2
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...	Braco - +/-35V will give you arround 50-55W/8ohm..... regarding quality of the amp - it is hard to say if it is good or bad - because all of us have a different taste of the music and also different speakers - one amplifier is not going to work at its best on one speaker or another different type of the speaker....so the best is to try it.... it can certainly be better made - with some improvements in this basic circuitry - but also you may like it how it sounds the way it is........ regards daniel

10th May 2007, 11:29 AM	#3
bracoraab diyAudio Member Join Date: Sep 2004 Location: under the boardwalk	Thanks a lot Daniel

10th May 2007, 11:33 AM	#4
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...	no problem - there is a lot other sch on the net that fit under 50-55W ......for example DX amp - that is a nice very good quality amp, also you have Project 101 from Rod Elliot that can be fitted inside 50W.... enjoy

10th May 2007, 12:26 PM	#5
sixtek diyAudio Member Join Date: Jan 2007	Hi, Max. PSU voltage is +/-30V for the OPA. Then I would use +/-25V supply rails. Calculating with 5V losses (that will be more: few Volts on supply caps, 1-2V on diode bridge, and few Volts in the mosfet) the output power will be 25W-RMS on 8Ohm and 50W-RMS on 4Ohm. So it's a 30W amp.

10th May 2007, 12:39 PM	#6
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...	sixtek - you are right - i missed that - i was to quick did not check for the voltage - no time ...

10th May 2007, 01:01 PM	#7
sixtek diyAudio Member Join Date: Jan 2007	No matter my friend

10th May 2007, 01:18 PM	#8
darkfenriz diyAudio Member Join Date: Jun 2004 Location: Warsaw	Is it designed by Dariusz Kulesza aka. Drakul ?

10th May 2007, 07:44 PM	#10
sparkle diyAudio Member Join Date: Oct 2003 Location: middle of nowhere...

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