Hi all!
This is a bit of a 'lazy/cheap/mad' idea of mine that on paper looks fine, but I was wondering what the reality was - has anyone tried this?
I've two spare but fettled Maplin MOSFET amps that I want to pop into an old Sony TA-F6B hulk (I was never really comfortable with the PSU or BJT power amp), and I have two options:
Plan A:
Use my existing spare 300VA toroid + a new softstart relay + resistor (ebay £4+) with new capacitors, perhaps twin bridges to separate the MOSFET supply and the amp PCBs...
..
OR Subversive plan D:
Buy two cheap 48V SMPS PSUs, hopefully quiet ones - yes, it's a lottery, but perhaps the POEs will do, and hook together as a bridge. That in theory gives nearly 300W too, and saves all the bridge and cap work and cost, but at the expense of separate rails for the OP transistors. In a way this is sort of more in the spirit of the original...
..
Plan Da:
A variation on this theme is to use a small 48ish Vdc split analogue supply for everything else, perhaps +/-35-40V would do as it's all regulated down to +/- 30V anyway, and the POEs just to power the MOSFETs themselves (the top source and bottom drain).
..
All thoughts welcome - thanks in advance! 🙂
This is a bit of a 'lazy/cheap/mad' idea of mine that on paper looks fine, but I was wondering what the reality was - has anyone tried this?
I've two spare but fettled Maplin MOSFET amps that I want to pop into an old Sony TA-F6B hulk (I was never really comfortable with the PSU or BJT power amp), and I have two options:
Plan A:
Use my existing spare 300VA toroid + a new softstart relay + resistor (ebay £4+) with new capacitors, perhaps twin bridges to separate the MOSFET supply and the amp PCBs...
..
OR Subversive plan D:
Buy two cheap 48V SMPS PSUs, hopefully quiet ones - yes, it's a lottery, but perhaps the POEs will do, and hook together as a bridge. That in theory gives nearly 300W too, and saves all the bridge and cap work and cost, but at the expense of separate rails for the OP transistors. In a way this is sort of more in the spirit of the original...
..
Plan Da:
A variation on this theme is to use a small 48ish Vdc split analogue supply for everything else, perhaps +/-35-40V would do as it's all regulated down to +/- 30V anyway, and the POEs just to power the MOSFETs themselves (the top source and bottom drain).
..
All thoughts welcome - thanks in advance! 🙂
You need to be careful that the SMPS units don't have one of the 48V supply lines tied to ground. If they have, you end up shorting one of the supplies. Any that has a 2 pin mains supply should be good, but check the isolation ratings.
