Where can i find info on possibly using a old computer power pack for a chip amp? Or is this a bad idea?
I have lots (more like to much) old computer parts and i have HP pavilion case that im taking the board out of and was thinking of using the power supply from it...... possibly and using the case , moded of course, for my chip amp.
I like the idea of using the switch on the power pack and the power cable and block and the grounding on it already.
What parts can you salvage out of old computers to use in DIY of this sort anyway?
Im new to DIY Audio but i really enjoy the concept before this i mostly worked on peoples computers and that is so straight forward its silly. But inturn ended up with people leftovers from upgrades. (read total computers mostly due to building new ones for them.
😉
Thanks
Sam
Need stuff i might have?
lol
I have lots (more like to much) old computer parts and i have HP pavilion case that im taking the board out of and was thinking of using the power supply from it...... possibly and using the case , moded of course, for my chip amp.
I like the idea of using the switch on the power pack and the power cable and block and the grounding on it already.
What parts can you salvage out of old computers to use in DIY of this sort anyway?
Im new to DIY Audio but i really enjoy the concept before this i mostly worked on peoples computers and that is so straight forward its silly. But inturn ended up with people leftovers from upgrades. (read total computers mostly due to building new ones for them.
😉
Thanks
Sam
Need stuff i might have?
lol
Surely a switching PSU which most computer ones have been for ages are a bad idea in any sort of audio????
John
John
I mean as far as I am concered switching PSU = Bad in audio but not any experience of a chip amp so maybe someone will know 100%
I see, im not up on my electical at all, but i thought i read somewhere that people had used computer power supplys for amps or maybe it was somthing else.
Im easily confused.
Im easily confused.
if youre talking abtou the sonic impact t amp, they susually mean the outboard transformers for laptops.
Well actually I am running a gainclone on a pair of computer smps supplies and it is utterly wonderful, 2 LM1875 based clone modules and it puts out enough watts to drive my full range system very loud. I have work to do as the supplies only put out 1 amp on the -12V and 8 on the +12V, there are ways around this, but I haven't fixed that yet.
In fact my Pre-amp is also running SMPS as well.
I have heard that you would hear switching noise etc, well my speaker system is very very revealing and I can't hear anything odd at all, just beautiful music. I have done comparisions with my regular torroid supplies and frankly I wouldn't use the torroids again in this application, the sound is grainy and loose by comparison.
Now having said the above, you will need two supplies and it is a fiddle to get them working and tidy them up and to get a good high amp supply for both + and - rails is a fiddle, you have to isolate the boards from the ground and re box the whole set-up so as not to electrocute yourself etc, so this is not a good first DIY task. BUT ultimately I think either this appraoch or battery power are the way to really turn a gainclone into a music maker of excellence.
Oh and heres the really great bit, these SMPS cost me just $2.00 each from a 2nd hand shop and I have a mate who can give me a few as well, he's a computer repair guy and smps's get upgraded all the time.
Food for thought.
In fact my Pre-amp is also running SMPS as well.
I have heard that you would hear switching noise etc, well my speaker system is very very revealing and I can't hear anything odd at all, just beautiful music. I have done comparisions with my regular torroid supplies and frankly I wouldn't use the torroids again in this application, the sound is grainy and loose by comparison.
Now having said the above, you will need two supplies and it is a fiddle to get them working and tidy them up and to get a good high amp supply for both + and - rails is a fiddle, you have to isolate the boards from the ground and re box the whole set-up so as not to electrocute yourself etc, so this is not a good first DIY task. BUT ultimately I think either this appraoch or battery power are the way to really turn a gainclone into a music maker of excellence.
Oh and heres the really great bit, these SMPS cost me just $2.00 each from a 2nd hand shop and I have a mate who can give me a few as well, he's a computer repair guy and smps's get upgraded all the time.
Food for thought.
I guess the way to look at it would be to figure out what the ripple in the SMPS is and how that compares to the ripple your Gainclone (or other) chip will reject. Probably easier said than done though?
🙂
🙂
I imagine the ripple will vary from one type of supply to another and I don't know how it would all be factored in, but I don't think that I have read of anyone who has tried SMPS for their clones saying they are going to go back to the conventional supply despite the fact that the power output is far less.
I have heard of some who are using batteries though and have used SMPS as well.
It is definitely worth a try, but I feel anyone new to cloning should get a std clone up and running well first, if for no other reason than to have a reference point to work from.
BTW computer supplies would need to be pretty well engineered in the first place as computers are pretty sensitive to power supply problems, I'm not sure though how they compare to the industrial type supplies that are now commonly available. None of those have plus and minus rails, but you can get around that.
I have heard of some who are using batteries though and have used SMPS as well.
It is definitely worth a try, but I feel anyone new to cloning should get a std clone up and running well first, if for no other reason than to have a reference point to work from.
BTW computer supplies would need to be pretty well engineered in the first place as computers are pretty sensitive to power supply problems, I'm not sure though how they compare to the industrial type supplies that are now commonly available. None of those have plus and minus rails, but you can get around that.
SMPS's are getting used now more than before. I believe it is possible to build one that performs highly, even though that wouldn't have been believed once. I still prefer to avoid them.
That said, what makes a high quality SMPS may not be what you find in a computer power supply, and they are very different depending on who made it and when.
Importantly, a chip amp has a fair power supply rejection ratio. On any other amp, you mightn't be so lucky. My amp has a fairly poor power supply rejection ratio for example, and noise would be more obvious.
Depending on what you choose, a computer power supply is a good source of switches, IEC sockets, fuse holders etc. but also high voltage caps.
That said, what makes a high quality SMPS may not be what you find in a computer power supply, and they are very different depending on who made it and when.
Importantly, a chip amp has a fair power supply rejection ratio. On any other amp, you mightn't be so lucky. My amp has a fairly poor power supply rejection ratio for example, and noise would be more obvious.
Depending on what you choose, a computer power supply is a good source of switches, IEC sockets, fuse holders etc. but also high voltage caps.
The PS case itself can also be handy, I have built clones into them and also used one to build a 15v regulated power supply, likewise a nice clone can be built into the CD drive case, so long as the power supply is seperate.
Beyond that the bearings in the hard drive can be used in DIY turntables, most folk scoff at this but they work really well, very high quality, the floppy drive can be used to run a turntable, there are also heatsinks etc that can be useful, lots of screws, nuts and bolts, small cabling, and probably more.
Maybe we need a DIY thread on "Ratting an old Computer!" Its a pity to see all that stuff thrown into landfill.
Beyond that the bearings in the hard drive can be used in DIY turntables, most folk scoff at this but they work really well, very high quality, the floppy drive can be used to run a turntable, there are also heatsinks etc that can be useful, lots of screws, nuts and bolts, small cabling, and probably more.
Maybe we need a DIY thread on "Ratting an old Computer!" Its a pity to see all that stuff thrown into landfill.
SMPS's are used more frequently nowadays for feeding amplifiers. The point might be that with an ordinary computer power supply you're having problems with the switching frequency (amongst others)
My gainclone is traditionally powered but I use a laptop powerblock to feed my Tripath 41Hz amp3 with great success. (with additional diode and filter cap)
One of the persons who have tried switching powersupplys for GC's is Nuuk (website decibel dungeon) although he uses specific models.
In short: switching powersupplies are not necessarily a bad thing but taking the first Computer power supply on your path is probably not going to give you the satisfaction that you will have from a good old tranny.
If that's ok with you than go ahead otherwise be in for some testing.
I;ve tested a regular AT supply with a large 10000uF filter cap on a car radio but I, as it was a low fi setup, cannot make any audioquality claims. It did pretty decent for the purpose.
My gainclone is traditionally powered but I use a laptop powerblock to feed my Tripath 41Hz amp3 with great success. (with additional diode and filter cap)
One of the persons who have tried switching powersupplys for GC's is Nuuk (website decibel dungeon) although he uses specific models.
In short: switching powersupplies are not necessarily a bad thing but taking the first Computer power supply on your path is probably not going to give you the satisfaction that you will have from a good old tranny.
If that's ok with you than go ahead otherwise be in for some testing.
I;ve tested a regular AT supply with a large 10000uF filter cap on a car radio but I, as it was a low fi setup, cannot make any audioquality claims. It did pretty decent for the purpose.
Boston-
Do a search in the forum using AT, ATX, SMPS, Switching Power supply, and several other keywords. There are currently over fifteen threads on modifying AT & ATX supplies for 12V input, modding them for a single +13.8V output, and modding them for Audio applications. Since you're probably not interested in the first two, just go with the audio-related threads.
There are several power supply gurus that post regularly (EVA, jackinnj, AndrewT, & others) who have a wealth of information, expertise and insight on everything SMPS and their contributions to this forum are priceless.
As you get into some of these threads, you will see that not only can a surplus AT or ATX box used for audio applications, but those who have done so, have obtained excellent results with their work. As always, there are pros & cons with doing so, but for your application (referencing zero one's comments) you can modify an AT box for use with gainclones or chipamps with good results.
Please take note on two things: First and foremost, you will be working with LETHAL voltages (120V in North America and 220-250V elsewhere) that are not isolated from the line, and second, not all computer SMPSs are good candidates for modification.
If you're using a unit of, say, 200W or more, and it has a half-bridge topology, and it has sufficient space in the output section for new caps & inductors, then you're in pretty good shape. If your supply is a flyback (single-ended), or if it lacks sufficient space for replacing the output caps, or if the AC input filter components (the common-mode inductor and accompanying filter caps) are not present, then you're better off looking for a higher-quality unit.
Steve
Do a search in the forum using AT, ATX, SMPS, Switching Power supply, and several other keywords. There are currently over fifteen threads on modifying AT & ATX supplies for 12V input, modding them for a single +13.8V output, and modding them for Audio applications. Since you're probably not interested in the first two, just go with the audio-related threads.
There are several power supply gurus that post regularly (EVA, jackinnj, AndrewT, & others) who have a wealth of information, expertise and insight on everything SMPS and their contributions to this forum are priceless.
As you get into some of these threads, you will see that not only can a surplus AT or ATX box used for audio applications, but those who have done so, have obtained excellent results with their work. As always, there are pros & cons with doing so, but for your application (referencing zero one's comments) you can modify an AT box for use with gainclones or chipamps with good results.
Please take note on two things: First and foremost, you will be working with LETHAL voltages (120V in North America and 220-250V elsewhere) that are not isolated from the line, and second, not all computer SMPSs are good candidates for modification.
If you're using a unit of, say, 200W or more, and it has a half-bridge topology, and it has sufficient space in the output section for new caps & inductors, then you're in pretty good shape. If your supply is a flyback (single-ended), or if it lacks sufficient space for replacing the output caps, or if the AC input filter components (the common-mode inductor and accompanying filter caps) are not present, then you're better off looking for a higher-quality unit.
Steve
I have done this, and i had noise coming from the speakers. I installed a 1mH inductor in series with the PSU output, and then 2200uF cap in parallel to ground after that. Noise was gone, amp sounds fine (it wasn't a hi-fi system to begin with, so IDK how it changed the quality, but it runs dead silent)
The highest voltage an unmodified PC power supply outputs is 12v, which is not enough for most audio. It should be relatively easy to modify (assuming half bridge design) for 24v or 48v by reworking the secondary rectifier without rewinding the transformer. For an ATX supply, the 5vsb part can be used as-is to run logic (with a LDO for lower voltage logic). The main output can be switched by the logic if needed for the design. With a little more work, even dynamic supply voltage (volume control only) can be implemented.
Laptop power supplies are around 20v or so and work great for small amps. A friend of mine actually used a 19v unit to run a dual BTL TPA3122D2 hybrid digital.
Laptop power supplies are around 20v or so and work great for small amps. A friend of mine actually used a 19v unit to run a dual BTL TPA3122D2 hybrid digital.
star882 said:
Standard computer SMPS dont use a bridge rectifier, they use one or a few high speed diodes in a single wave configuration, with each voltage winding terminating in a common ground point.
A computer SMPS doesnt really work like a transformer, its more of a "switched inductor", and you cant treat them like a transformer unless it has a symmetrical drive. Very few have sym drive, they use chopped DC instead.
You can vary the voltage up or down a few percent by changing the feedback regulation, but other then that, not much you can do.
I built a little TDA2030 chip amp for my friend, running 0 and 12 volts from a big old computer supply. I wasn't expecting it to be very good, but it really wasn't bad at all. There was SMPS noise, so i used the 1mH inductors on both supply rails (ground, too), and the noise was totally gone. A filter cap was added on either side of the inductors just for good measure (CLC filter). It was hard to tell exactly how it effected the sound, as her speakers were cheap, but to my ears it was much better than the old AV receiver she was using. The TDA2030 had good bass, but probably because of the 12V supply, it started clipping at above-normal-listening-level volumes.
All the AT and some ATX supplies I have taken apart are of a half bridge design, which is symmetrical drive. The newer ATX supplies are indeed single ended forward/flyback.Rainwulf said:
Most laptop supplies are flyback, but I have encountered an unusual push-pull design.
Ah, its good that someone else knows what im talking about.
GOOD Power supplies for PCs often use half bridge symmetrical drive or push pull, the current psu im using in my watercooled PC is a delta electronics model, and it actually has two boards on it, one high side, and one low side. Its proper symmetrical drive, and you can tell by the amazing regulation it has. The high side deals with proper regulation of the high voltage DC, power facter correction and proper drive of the main chopper transistors, and the low side has the main transformer, and all the capacitors and rectifiers. its an amazing piece of work!
Most standard cheap computers psus however, not much you can do apart from physically rewiring the main transformer.
I have encountered a push pull in a laptop psu, it was designed for converting 12 volts to 19 volts.
Also in computer power suppliers, the inductor after the main transformer does as much work as the transformer itself does!
Efficient design thats for sure, all based around the smallest component count im guessing.
GOOD Power supplies for PCs often use half bridge symmetrical drive or push pull, the current psu im using in my watercooled PC is a delta electronics model, and it actually has two boards on it, one high side, and one low side. Its proper symmetrical drive, and you can tell by the amazing regulation it has. The high side deals with proper regulation of the high voltage DC, power facter correction and proper drive of the main chopper transistors, and the low side has the main transformer, and all the capacitors and rectifiers. its an amazing piece of work!
Most standard cheap computers psus however, not much you can do apart from physically rewiring the main transformer.
I have encountered a push pull in a laptop psu, it was designed for converting 12 volts to 19 volts.
Also in computer power suppliers, the inductor after the main transformer does as much work as the transformer itself does!
Efficient design thats for sure, all based around the smallest component count im guessing.
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