Can project 03 drive a sub (4ohm driver)

goldyrathore · 27th March 2005, 07:34 AM

Hi,

I am in need of a sub amp which can give 100Watts RMS of clean power for sub use. How good is project 03 at Rod Elliot's site? It is obvious that I will have to use it with output transistors in parallel for a 4ohm driver. How much of clean power can it give (at what supply voltage ?) and what is the damping factor which is critical to have a tight control of the driver?
Also if I put more transistors in parallel. Can it drive 2 Ohm loads.
I am particularly interested in this amp since it uses readily available parts.

Thanks in advance,
Goldy

kinser · 27th March 2005, 08:39 AM

goldyrathore,
Hi,

I think you should use project 03a which is an updated circuit of project 03, also if you look at the shcematic on project o3 you will se that it sais:
"Figure 1 - 60W Power Amplifier Original Circuit Diagram (
Don't Use This Circuit! )"

Hope I helped you!

Kinser

goldyrathore · 27th March 2005, 04:20 PM

Hi,
As I said earlier I am interested in this amp in particular because the components are vailable locally here in Bangalore, India. The amp in Figure 1 is not to be used but Figure 1a can be used. I am concerned about the fact that "The amp is capable of driving 4 Ohms, but it is starting to push the limits of the transistors".
Any suggestions. Will parallel operation of 2955 and 3055 solve the 4ohm load problem?
Thanks,
Goldy

kinser · 27th March 2005, 04:43 PM

goldyrathore,
I saw figure 1a and i think that u could just add an extra pair of output transistor and you are ready to go! but i would go with project 3a if I where u!

Kinser

edl · 27th March 2005, 05:06 PM

hello Goldyrathore!

your idea will works!

you know, here is the article:
http://sound.westhost.com/project03.htm

here there is a figure, that one:
http://sound.westhost.com/p03_fig2.gif

I made a two channel stereo "P03" amp for with 4ohm speakers.
I used an 56V-CT (2*28V) toroidal transformer, rated 200VA.
This way I had 100W-RMS on 4ohm.

The 2955/3055 pair don't likes +/-40V rails, so I used two pairs of BD911/BD912 per channel. This transistors are so cheap, but they are excellent!
If the 911/912 are not available in Bangalore, you can use any other complementary power devices, with Uce min 80V!
If you have got any question or problems, let's answer!

Good luck, my friend, Hello from Hungary!

goldyrathore · 30th March 2005, 02:33 PM

Hi,

Has anybody tried bridging this amp to get more power? Since I want to use it for a sub, I think it is better to have some headroom.

Thanks in advance,
Goldy

27th March 2005, 07:34 AM	#1
goldyrathore diyAudio Member Join Date: Nov 2002 Location: Bangalore, India	Can project 03 drive a sub (4ohm driver) Hi, I am in need of a sub amp which can give 100Watts RMS of clean power for sub use. How good is project 03 at Rod Elliot's site? It is obvious that I will have to use it with output transistors in parallel for a 4ohm driver. How much of clean power can it give (at what supply voltage ?) and what is the damping factor which is critical to have a tight control of the driver? Also if I put more transistors in parallel. Can it drive 2 Ohm loads. I am particularly interested in this amp since it uses readily available parts. Thanks in advance, Goldy __________________ Audio enthusiast/hobbyist

27th March 2005, 04:20 PM	#3
goldyrathore diyAudio Member Join Date: Nov 2002 Location: Bangalore, India	My clarification Hi, As I said earlier I am interested in this amp in particular because the components are vailable locally here in Bangalore, India. The amp in Figure 1 is not to be used but Figure 1a can be used. I am concerned about the fact that "The amp is capable of driving 4 Ohms, but it is starting to push the limits of the transistors". Any suggestions. Will parallel operation of 2955 and 3055 solve the 4ohm load problem? Thanks, Goldy __________________ Audio enthusiast/hobbyist

30th March 2005, 02:33 PM	#6
goldyrathore diyAudio Member Join Date: Nov 2002 Location: Bangalore, India	Can I bridge this amp to get more power? Hi, Has anybody tried bridging this amp to get more power? Since I want to use it for a sub, I think it is better to have some headroom. Thanks in advance, Goldy __________________ Audio enthusiast/hobbyist

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27th March 2005, 08:39 AM	#2
kinser diyAudio Member Join Date: Jan 2004 Location: R'aanana	goldyrathore, Hi, I think you should use project 03a which is an updated circuit of project 03, also if you look at the shcematic on project o3 you will se that it sais: "Figure 1 - 60W Power Amplifier Original Circuit Diagram ( Don't Use This Circuit! )" Hope I helped you! Kinser

27th March 2005, 04:43 PM	#4
kinser diyAudio Member Join Date: Jan 2004 Location: R'aanana	goldyrathore, I saw figure 1a and i think that u could just add an extra pair of output transistor and you are ready to go! but i would go with project 3a if I where u! Kinser

27th March 2005, 05:06 PM	#5
edl diyAudio Member Join Date: Oct 2004	hello Goldyrathore! your idea will works! you know, here is the article: http://sound.westhost.com/project03.htm here there is a figure, that one: http://sound.westhost.com/p03_fig2.gif I made a two channel stereo "P03" amp for with 4ohm speakers. I used an 56V-CT (2*28V) toroidal transformer, rated 200VA. This way I had 100W-RMS on 4ohm. The 2955/3055 pair don't likes +/-40V rails, so I used two pairs of BD911/BD912 per channel. This transistors are so cheap, but they are excellent! If the 911/912 are not available in Bangalore, you can use any other complementary power devices, with Uce min 80V! If you have got any question or problems, let's answer! Good luck, my friend, Hello from Hungary!

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