50 Watt Amp Power Supply Critique - Electronic Circuits Projects Diagrams Free

Johnson777717 · 4th March 2004, 11:10 PM

Hey folks!
I'm trying to come up with a power supply for a 50 watt amp that I'm building. The Amp recommended input voltage is +- 29 volts, maximum +- 44volts. I'm not sure how much current the amp will draw, because the datasheet doesn't explicitly tell me so. I won't be driving the amp very hard because I'm only using it for my computer sound system. I have 6 speakers that I want to run from the computer, but the computer doesn't have enough power to push all 6 speakers without distorting at medium to high decibel levels. Thus, I'm creating this amp. Nothing special really, just using a STK4152II Stereo Amp that I got from a stereo with a broken CD player.

Anyway, as stated, I'm trying to design a PS for the amp. Will this circuit work? I've redrawn a design by Elliott Sound Products, included the 2200uF caps in parallel instead of 4700uF caps (I don't have these 4700 uf caps so i'm improvising.) Will this work? Does anyone have any suggestions for improvement?

Thank you very much for your support! Have a great day!

Johnson777717 · 4th March 2004, 11:10 PM

Heres the schematic

Russlk · 5th March 2004, 03:47 AM

This supply will provide 39 volts between + and - but ground will not be in the middle unless you are lucky.

**Nigel Goodwin** · 5th March 2004, 06:15 AM

The transformer should be centre tapped, with the tap going to the middle of the two capacitors (as it is in the original circuit). You also don't need the second bridge rectifier, it's for preventing ground loops in PA setups.

As mentioned previously, two single 2200uF capacitors will probably be fine, but more capacitance is always good.

I hope you're not planning using computer speakers with this, a 50W amplifier is likely to blow them to pieces - the ratings on them are usually a work of complete fiction!.

Johnson777717 · 5th March 2004, 04:20 PM

Thanks for the reply guys. The speakers that I have are 8 ohm, 6" speakers rated at 60watts, so I think we'll be okay. Nigel, thanks for checking though, I appreciate your concern.

I suppose that I need to go get a center tapped transformer. I was hoping that I could get away without using a CT transformer.

Thanks for your help guys!

**Nigel Goodwin** · 5th March 2004, 09:45 PM

Quote:

Originally Posted by Johnson777717

Thanks for the reply guys. The speakers that I have are 8 ohm, 6" speakers rated at 60watts, so I think we'll be okay. Nigel, thanks for checking though, I appreciate your concern.

Just making sure :lol: you see so many computer speakers which say '400W' or '200W' on them (but use 3" drivers with 3W stamped on the magnet!).

Quote:

I suppose that I need to go get a center tapped transformer. I was hoping that I could get away without using a CT transformer.

It 'may' be possible, but would require a redesign of the amplifier (assuming the STK could be configured that way) - I really don't advise it.

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4th March 2004, 11:10 PM	(permalink)
Johnson777717	50 Watt Amp Power Supply Critique Hey folks! I'm trying to come up with a power supply for a 50 watt amp that I'm building. The Amp recommended input voltage is +- 29 volts, maximum +- 44volts. I'm not sure how much current the amp will draw, because the datasheet doesn't explicitly tell me so. I won't be driving the amp very hard because I'm only using it for my computer sound system. I have 6 speakers that I want to run from the computer, but the computer doesn't have enough power to push all 6 speakers without distorting at medium to high decibel levels. Thus, I'm creating this amp. Nothing special really, just using a STK4152II Stereo Amp that I got from a stereo with a broken CD player. Anyway, as stated, I'm trying to design a PS for the amp. Will this circuit work? I've redrawn a design by Elliott Sound Products, included the 2200uF caps in parallel instead of 4700uF caps (I don't have these 4700 uf caps so i'm improvising.) Will this work? Does anyone have any suggestions for improvement? Thank you very much for your support! Have a great day!

5th March 2004, 03:47 AM	(permalink)
Russlk	This supply will provide 39 volts between + and - but ground will not be in the middle unless you are lucky. __________________ see my website: www.geocities.com/russlk

5th March 2004, 06:15 AM	(permalink)
Nigel Goodwin	The transformer should be centre tapped, with the tap going to the middle of the two capacitors (as it is in the original circuit). You also don't need the second bridge rectifier, it's for preventing ground loops in PA setups. As mentioned previously, two single 2200uF capacitors will probably be fine, but more capacitance is always good. I hope you're not planning using computer speakers with this, a 50W amplifier is likely to blow them to pieces - the ratings on them are usually a work of complete fiction!.

5th March 2004, 04:20 PM	(permalink)
Johnson777717	Thanks for the reply guys. The speakers that I have are 8 ohm, 6" speakers rated at 60watts, so I think we'll be okay. Nigel, thanks for checking though, I appreciate your concern. I suppose that I need to go get a center tapped transformer. I was hoping that I could get away without using a CT transformer. Thanks for your help guys!