Which discrete amp for a +/- 48v supply?

[simple simon]

I started this on the chip-amp forum but perhaps that was a mistake. Sorry for those who cross read.

I have several (4 in fact) +/- 48vdc power supplies. Are there any already developed amps that can use such a supply? I'm not looking for hi-fi really more cheap, simple and reliable. Application is general PA for live music. I can solder and follow a circuit diagram but I'm not clever enough to derive what component values should be.

Many thanks for any pointers.

Simon

[nigelwright7557]

What is your skill level ?

You can buy loads of modules online or on ebay just to bolt together yourself.
Or you can build your own on your own pcb or stripboard.

Maplin do some good cheap modules.
Maplin Electronics ? Website- 1.5TB Verbatim External Hard Drive Free Delivery

[jaycee]

I would say Dr Bora's "Legend" amp would be a good fit here. Look here - :::Borina Amaterska Svastara::: (in the "Pojacala" section). His site is in Serbian but there is a schematic diagram and a PCB layout there.

Unfortunately Maplin have nothing but crap now. They have some Velleman "200W" amp (really that's peak power, it's not even 80W RMS) but they don't have the transformer or heatsink for it!

[nigelwright7557]

[QUOTE=jaycee;2182816
Unfortunately Maplin have nothing but crap now. They have some Velleman "200W" amp (really that's peak power, it's not even 80W RMS) but they don't have the transformer or heatsink for it![/QUOTE]


200watts times 0.707 = 141watts RMS according to my calculations.

The Maplin kits come with a nice pcb and all the components ready to solder in.

OK the current Maplin kits arent a patch on the 225WRMS power amp they did in the 1980's but they are worth a look for a beginner.

For transformers and heatsinks there is Welcome to rswww.com and Farnell United Kingdom | world-leading distributor of electronic and maintenance, repair and operations products.

I started in 1980 with a couple of Maplins kits and found them a useful start.

[apexaudio]

Originally Posted by simple simon

I started this on the chip-amp forum but perhaps that was a mistake. Sorry for those who cross read.

I have several (4 in fact) +/- 48vdc power supplies. Are there any already developed amps that can use such a supply? I'm not looking for hi-fi really more cheap, simple and reliable. Application is general PA for live music. I can solder and follow a circuit diagram but I'm not clever enough to derive what component values should be.

Many thanks for any pointers.

Simon

I suggest you:
MOSFET Amplifier IRFP240/IRFP9240
Work well on +/-48VDC
Regards

[Mooly]

Have a look at,
Your Search Results | CPC

heatsink,
VELLEMAN KIT|HSVM100|HEAT SINK FOR K8060 | CPC From This Range&MER=e-bb45-00001003

[ben12345]

Doesn't that Velleman '200w' kit need a maximum of a 30-0-30 Vac transformer? So maybe that one is no good for the OP.

That is unless these +/- 48v power supplies are SMPS which can be tweaked down to 42v rails.

[Mooly]

Originally Posted by ben12345

Doesn't that Velleman '200w' kit need a maximum of a 30-0-30 Vac transformer? So maybe that one is no good for the OP.

That is unless these +/- 48v power supplies are SMPS which can be tweaked down to 42v rails.

I think in practice it would be fine... a 30-0-30 transformer if it's around 120 to 160va will have a regulation of around 7 to 10% so that gives a worst case of around -/+46.6 volts DC at no current draw, but yes it's wise to point it out.

[vadi]

Hi,
are these amps suggested suitable for transformers with 48V secondaries?
So I think the real voltage would be about 48V*Pi=67V?

[jaycee]

No they aren't suitable. To be honest I do not think they are even suitable for 40V DC supplies - 35V is what I would use with them. It only uses a single pair of TIP142/147 darlington transistors.