Hello All
I searched the Design & Build > Equipment & Tools forums and did not find anything similar to the following idea, so I thought I would through it out there for other diy’ers consideration.
A couple of years ago, when I started experimenting with different audio amplifier designs (200W / 8 ohms), I needed some kind of bench power supply capable of providing +/- 60V at around 5 amps peak. Most of the commercial dual power supplies that met those requirements are very expensive, and tend to be regulated. But audio amplifiers at this power level rarely use regulated power supplies, so I decided that an unregulated supply would be adequate, or even preferable for testing purposes.
I thought I would just build an open frame unregulated power supply, similar to what would actually be used in a completed amplifier, and power it from a 4.5 amp Variac I have. With that combination I could power up slowly, for testing, at any voltage up to the maximum of the unregulated supply. The 5 amp requirement implies using a transformer in the 300 - 400VA range. I selected 300VA because a model with two 50V secondary’s was available at the time from AnTek. I used the Universal PSU boards from the diy Audio Store, a pair of bridge rectifiers and a total of 27,200 microfarad of capacitance per rail. Total cost was $162.00. If one needed to buy the Variac also, they are available for around 50 – 60 dollars. Pictures and the schematic are attached.
Remember, it is open frame, so you have to be careful. I keep mine a couple of feet away from my work area. Of course you could also enclose it and put volt and amp meters on it.
Cheers
ceulrich
I searched the Design & Build > Equipment & Tools forums and did not find anything similar to the following idea, so I thought I would through it out there for other diy’ers consideration.
A couple of years ago, when I started experimenting with different audio amplifier designs (200W / 8 ohms), I needed some kind of bench power supply capable of providing +/- 60V at around 5 amps peak. Most of the commercial dual power supplies that met those requirements are very expensive, and tend to be regulated. But audio amplifiers at this power level rarely use regulated power supplies, so I decided that an unregulated supply would be adequate, or even preferable for testing purposes.
I thought I would just build an open frame unregulated power supply, similar to what would actually be used in a completed amplifier, and power it from a 4.5 amp Variac I have. With that combination I could power up slowly, for testing, at any voltage up to the maximum of the unregulated supply. The 5 amp requirement implies using a transformer in the 300 - 400VA range. I selected 300VA because a model with two 50V secondary’s was available at the time from AnTek. I used the Universal PSU boards from the diy Audio Store, a pair of bridge rectifiers and a total of 27,200 microfarad of capacitance per rail. Total cost was $162.00. If one needed to buy the Variac also, they are available for around 50 – 60 dollars. Pictures and the schematic are attached.
Remember, it is open frame, so you have to be careful. I keep mine a couple of feet away from my work area. Of course you could also enclose it and put volt and amp meters on it.
Cheers
ceulrich
Attachments
Here is another option +60 or -60V
For +/- 60V at 5A it would require two supplies.....(600W)
Matrix MPS-6005D+ Variable Linear Regulated Adjustable DC Power Supply 60V 5A Low Ripple and Noise for Laboratory: https://www.amazon.com/Matrix-Variable-Linear-Laboratory-Alligator/dp/B08FC4YT1N?th=1
$129.99 & FREE Returns, CouponSave an extra 10%
For +/- 60V at 5A it would require two supplies.....(600W)
Matrix MPS-6005D+ Variable Linear Regulated Adjustable DC Power Supply 60V 5A Low Ripple and Noise for Laboratory: https://www.amazon.com/Matrix-Variable-Linear-Laboratory-Alligator/dp/B08FC4YT1N?th=1
$129.99 & FREE Returns, CouponSave an extra 10%
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