View Full Version : DIY PSU for Spitfire DAC
Hi there,
My son has just bought a Firestone Spitfire II DAC which comes with a wall wart power supply. It works fine and sounds pretty nice but I can't help but think the ugly little power supply would not be hard to improve on.
Looking into it a little it seems that DAC power supplies are a little more involved than I thought. Firestone's own version is £100 and I was hoping to find or build a cheaper alternative. Any ideas?
Hi Colin,
This isn't my area of expertise, but you may also wish to post your query in the DIY section :)
Marco.
Good idea. Why not move it?
Done! :)
So, guys, what's your advice for Colin? :cool:
Marco.
Is the supply DC or AC? If it is AC there is not an awful lot you can do except swapping the small tranny in the wart for a larger toroidal tranny, which MIGHT make an improvement.
I have recently made a better supply for a Dac which takes a aplit rail AC supply. If you check which rails are + and - you can add a regulated and smoothed DC supply, thereby having two stages of regulation.
I used one of these boards:-
http://i73.photobucket.com/albums/i239/saxonsex/GenericRectifierBoard.jpg
The supplied wall wart puts out DC 24V 0.5A.
Their upgraded PSU is described as "a cleaner and more powerful power supply unit" and all of the revues I've read of it suggest it works. Everyone thinks it's a good upgrade, I've not seen anyone say it wasn't worth it.
Getting a higher capacity 24V supply would be easy enough but from what I've read the stability and accuracy of the voltage seem just as important. I don't want to waste money buying or building something that is not going to work ideally.
There are several schools of thought as to what constitutes a smooth quiet PS. Some say you should have chokes, some say not.
You could try a TeddyRegged PS (see PinkFishMedia or Teddy Pardos site for info) also have a look at the schematic for the Carlos Filipe PS.
I suspect you could build one for £40 - 50. You pays your money you takes your choice.
Rob.
IME this is a bit of a minefield.
I used a TeddyReg on my Beresford 7510 and Caiman powered with a toroidal transformer and some big low ESR caps and that made a huge difference to the sound over the standard and even upgraded switch mode supplies.
So far though, I've had no luck improving on the wallwart for the Arcam rDac. I've tried both the reconfigured TeddyReg for 6V (the Beresfords are 12 -15) and some pretty hefty bench power supplies. The switcher actually does a rather good job and I imagine improving upon it is going to require a specifically tailored linear supply.
I don't think it's a fact of life that SMPS is always worse than linear for hi-fi given a good design.
Lots of options, could be about 30 to 50 quid just for the transformer.case and fittings , you then need a regulated AC to DC supply circuit . If you can build on vero board you can do something pretty cheap based around basic LM317, if not theres a few other options which will be good but cost more
HighFidelityGuy
24-12-2010, 12:08
I think it's partly going to depend on how high quality the official upgraded supply is. If it's an advanced design similar to what you can make with a SuperTeddyReg then for £100 I'd be tempted to go with the official one. I say this because I made a TeddyReg supply earlier this year and it probably cost me over £100 once I'd factored in the aluminium case, rectifier, big smoothing cap and toroid trany. If however the official supply is just a simple transformer, rectifier, smoothing cap and voltage regulator design, then you could build one of those for under £100. Especially if you used a plastic case and non-boutique components. So I'd do some research and try to find out a bit more about the official supplie's design.
However I wouldn't even consider trying unless you are quite competent at electronics and have a good understanding of basic power supply design and electrical safety. Definitely don't try if it's your first project. :)
Ali Tait
24-12-2010, 13:54
Colin, whereabouts are you? I have some very good regulated linear supplies, and it so happens I have a spare 24v one you could borrow to try if you like.
I have a spare 24v one you could borrow to try if you like.
Thank you, that's very kind. And also practicable as I'm not too far away. Near Airdrie if you know where that is?
IME this is a bit of a minefield
I'm beginning to think so. Unless you use a design that is complementary to the DAC you could easily end up with something that offers little improvement. Even if it was better, unless you'd also tried the manufacturer's one, you still wouldn't know if it was as good as the box made for the job. When you consider that the cost of a DIY supply might easy approach the cost of the manufacturer's version it is starting to seem less attractive. It would be a lot better if you knew exactly what that PSU put out!
Ali Tait
24-12-2010, 14:35
Yes indeed I do. Perhaps we could arrange something after Hogmanay?
Yes indeed I do. Perhaps we could arrange something after Hogmanay?
Sure, cool. Thank you :0)
If you'd like pop in for a visit when you're down this way that would be fine. I've got four more Stages of Mana to put in come the new year. If you wait until after I've done that it should be interesting. Or I'm happy to come to you, it's not that far.
Talk to you about it in a few weeks.
Ali Tait
24-12-2010, 15:35
Yes sure thanks, I'd like to hear the 'Briks. Never heard any before.
I'd like to hear the 'Briks. Never heard any before
What Briks do is a very conventional sound, writ large! They are not the most transparent or dynamic speakers you'll ever hear. They do a pleasant, coherent and tuneful sound like any number of other speakers of the era. Where they score is that they'll do it louder and deeper than most. Where as your average decent speaker might have tight bass to maybe 60Hz Briks have the same quality of bass to below 30 and make it sound easy.
It doesn't sound like much, and the truth is that it isn't, but that last mile is hard to do. It's quality deep bass that costs money. Apart from that they sound pretty much the same as Linn Kans, maybe not even that good.
Ali Tait
24-12-2010, 17:00
Cool. Be interesting to hear them. I'm currently fiddling with a pair of open baffles with two Eminence Alpha 15 inch woofers and a Visaton B200 full ranger per side, crossed over at 200 Hz and actively driven via a Behringer DCX 2496.
I'm currently fiddling with a pair of open baffles with two Eminence Alpha 15 inch woofers and a Visaton B200 full ranger per side
I'd quite like to hear that too actually. Large, high efficiency speakers have always made sense to me, theoretically, but I've not heard many.
Ali Tait
24-12-2010, 17:35
I could bring them along if you like.
I could bring them along if you like.
I'm not into pulling my system apart these days, unless I have to! Besides, I doubt they'd give their best just plonked in the middle of the floor. Are they not quite large anyway?
Ali Tait
24-12-2010, 20:06
Yes but not that heavy. We can leave it and you could come over sometime if you want a listen.
Yes but not that heavy. We can leave it and you could come over sometime if you want a listen.
I would prefer that if you're happy with that? I know that if I brought my speakers to your house I would not be able to get them sounding as good as they do in mine. It takes a lot of faffing around to get things working at their best.
Ali Tait
24-12-2010, 20:23
Yes indeed,but I'm not too worried about that,it's just fun to meet other nutters in this obsession of ours and have a chat and a listen. Doesn't need to be too serious. S'all about fun is it not?
S'all about fun is it not?
Should be ;0)
Ali Tait
24-12-2010, 20:40
Ok, I'll come over for a listen and bring the PS, and you can reciprocate at your convenience. :)
Ok, I'll come over for a listen and bring the PS, and you can reciprocate at your convenience. :)
Deal.
Knowing both you guys, I think you'll get on really well :)
Colin, make sure Ali gets to sample Val's superb home-baking... Never mind the hi-fi, some things are much more important! :eyebrows:
Marco.
Knowing both you guys, I think you'll get on really well
Oh, kiss of death there then! ;0)
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