Folks:
I've got a Schiit Modi Multibit DAC that eats wall warts. Okay, that isn't exactly true, but I'm now on my third wall wart supplied by Schiit (one originally supplied by Schiit and the other two were replacements supplied under warranty by Schiit). All three have been 16 VAC / 500mA supplies. My Modi's warranty has now expired and I am anticipating the seemingly inevitable death of the latest Schiit-supplied wall wart.
I wrote to Schiit and asked if there was any reason why I shouldn't buy a replacement wall wart or power supply off ebay. There are many 16VAC supplies available, mostly with 4 or 4.5A ratings. A Schiit technician responded and urged me to stick with 16 VAC / 500mA supplies only. I don't understand why. Can anyone explain to me why I should avoid a 4 or 4.5A supply?
Regards,
Scott
I've got a Schiit Modi Multibit DAC that eats wall warts. Okay, that isn't exactly true, but I'm now on my third wall wart supplied by Schiit (one originally supplied by Schiit and the other two were replacements supplied under warranty by Schiit). All three have been 16 VAC / 500mA supplies. My Modi's warranty has now expired and I am anticipating the seemingly inevitable death of the latest Schiit-supplied wall wart.
I wrote to Schiit and asked if there was any reason why I shouldn't buy a replacement wall wart or power supply off ebay. There are many 16VAC supplies available, mostly with 4 or 4.5A ratings. A Schiit technician responded and urged me to stick with 16 VAC / 500mA supplies only. I don't understand why. Can anyone explain to me why I should avoid a 4 or 4.5A supply?
Regards,
Scott
I'm not familiar with the product, however your description of it being 16V AC suggests it is nothing more than transformer in a box and if so, the only likely failure point would be some inbuilt thermal fuse in the primary winding going open circuit.
As to using a different supply, well nothing obvious comes to mind. A larger capacity supply will have better regulation (difference between no load and full load voltage) but will also be physically larger.
I suppose there are safety factors along the lines of the replacement being able to deliver a much higher current in the event of a fault in the equipment it supplies, however if that equipment is correctly designed then it should incorporate suitable fusing at the AC inlet.
As to using a different supply, well nothing obvious comes to mind. A larger capacity supply will have better regulation (difference between no load and full load voltage) but will also be physically larger.
I suppose there are safety factors along the lines of the replacement being able to deliver a much higher current in the event of a fault in the equipment it supplies, however if that equipment is correctly designed then it should incorporate suitable fusing at the AC inlet.
Hi SRMcGee
Can you hold the wall wart in your hand for 1 minute?
If not then measure the open circuit voltage, loaded voltage and the current to the Schiit DAC. If the current is >400ma (20% DERATING) the failure is overheating and the primary protective fuse will open.
If the current is >400ma then replace the wall wart with a PS rated for the load.
Duke
Can you hold the wall wart in your hand for 1 minute?
If not then measure the open circuit voltage, loaded voltage and the current to the Schiit DAC. If the current is >400ma (20% DERATING) the failure is overheating and the primary protective fuse will open.
If the current is >400ma then replace the wall wart with a PS rated for the load.
Duke
Mooly:
Yup, that sounds right to me. I should have mentioned in my original post that the Modi’s wall wart is plugged into a Furman AC215, along with the associated server. It’s unclear to me what is causing the untimely death of the wall warts, but I’m game to try something different. Hence the use of a beefier power supply. The ones on eBay are ostensibly intended for flat screen televisions and computers; in any event, at about 8 USD a pop, delivered, they seem like a far better deal than buying another 500mA piece o’ junk from Schiit.
Thanks for the prompt reply.
Regards,
Scott
Yup, that sounds right to me. I should have mentioned in my original post that the Modi’s wall wart is plugged into a Furman AC215, along with the associated server. It’s unclear to me what is causing the untimely death of the wall warts, but I’m game to try something different. Hence the use of a beefier power supply. The ones on eBay are ostensibly intended for flat screen televisions and computers; in any event, at about 8 USD a pop, delivered, they seem like a far better deal than buying another 500mA piece o’ junk from Schiit.
Thanks for the prompt reply.
Regards,
Scott
Audio1Man:
The wall wart is barely warm to the touch. As mentioned in my last post, it is plugged into a Furman spike protector. My uninformed assumption is that Schiit is supplying lesser-quality wall warts, though the fact that that would be a dumb thing to do gives me pause; the folks at Schiit aren’t dummies.
In any event, if the current wall wart blows up and I replace it with an eBay-sourced brick and then the Modi dies, I’ll have good evidence that I’m the dope. After all, I’ve been warned.
Regards,
Scott
The wall wart is barely warm to the touch. As mentioned in my last post, it is plugged into a Furman spike protector. My uninformed assumption is that Schiit is supplying lesser-quality wall warts, though the fact that that would be a dumb thing to do gives me pause; the folks at Schiit aren’t dummies.
In any event, if the current wall wart blows up and I replace it with an eBay-sourced brick and then the Modi dies, I’ll have good evidence that I’m the dope. After all, I’ve been warned.
Regards,
Scott
Must be more popular over there.
I could find barely any 16V ac supplies - only DC switching supplies.
I suspect your DAC requires ac to produce a split (+/-) supply.
I could find barely any 16V ac supplies - only DC switching supplies.
I suspect your DAC requires ac to produce a split (+/-) supply.
I bought 4 Chinese 12 volt DC 2amp wall warts.
In a week two had blown.
So I measured the current taken by my circuit and it was less than 400mA.
I can only guess they are just cheap and nasty.
They don't have air vents in them so any heat is just going to accumulate and eventually blow the thermal fuse.
In a week two had blown.
So I measured the current taken by my circuit and it was less than 400mA.
I can only guess they are just cheap and nasty.
They don't have air vents in them so any heat is just going to accumulate and eventually blow the thermal fuse.
I'm using a Triad WAU16-2400 wall transformer for my Peavey PV8 mixer. 16 vac, 2.4 amps. It's 8 months old and still works fine. Like most things from newark/farnell, it is not counterfeit.
I can't evaluate the circuit of the DAC through the internet, but if your unit is drawing more than 500 ma I'd suspect the power supply DC caps. I don't know where you bought this, but I've bought things from W*****t that had bad PS caps out of the box brand new. Like an Apex DTV converter that had wiggly lines in the picture the first two minutes it was powered on. Always a bargain at W******.
I can't evaluate the circuit of the DAC through the internet, but if your unit is drawing more than 500 ma I'd suspect the power supply DC caps. I don't know where you bought this, but I've bought things from W*****t that had bad PS caps out of the box brand new. Like an Apex DTV converter that had wiggly lines in the picture the first two minutes it was powered on. Always a bargain at W******.
Some wall warts may be pretty close rated with regard to mains input voltage and saturation. Just a thought but is your mains 'clean' and and a decent sine wave and not flat topped/bottomed. Also check the mains voltage isn't high. Either of those things could cause sudden overheating as the transformer is suddenly pushed into magnetic saturation of the core.
Mains issues can be random of course and be OK 99% of the time.
Good luck 🙂
Mains issues can be random of course and be OK 99% of the time.
Good luck 🙂
Why are you:
As to wall wart current capability, some worry about "Factory specs 500mA ... will my overrated 1/2/4 A aftermarket transformer burn my device?"
Not at all; excess voltage is a great destroyer; excess current capability is just that, a capability, your device will pull whatever it needs and nothing more.
Plug your wall wart straight into the wall and remove *one* uncontrolled variable from the mix, period.
As to wall wart current capability, some worry about "Factory specs 500mA ... will my overrated 1/2/4 A aftermarket transformer burn my device?"
Not at all; excess voltage is a great destroyer; excess current capability is just that, a capability, your device will pull whatever it needs and nothing more.
Go to Home Depot and get a doorbell transformer. 16VAC
https://www.homedepot.com/p/Newhous...PIPHorizontal2_rr-_-304225270-_-307787405-_-N
https://www.homedepot.com/p/Newhous...PIPHorizontal2_rr-_-304225270-_-307787405-_-N
Jim:
A great idea, but not the most cost-effective. About $18 for the transformer (including tax but not driving time or cost), a few bucks for the ancillary wiring and connectors and your transformer would do the trick. No box, but probably not that important. But a 16VAC brick from ebay will cost about $8, delivered.
I'll buy a brick and keep it in reserve for the day my last Schiit-supplied wall wart dies.
JMFahey:
Yeah, I can do that.
Thanks everyone!
Regards,
Scott
A great idea, but not the most cost-effective. About $18 for the transformer (including tax but not driving time or cost), a few bucks for the ancillary wiring and connectors and your transformer would do the trick. No box, but probably not that important. But a 16VAC brick from ebay will cost about $8, delivered.
I'll buy a brick and keep it in reserve for the day my last Schiit-supplied wall wart dies.
JMFahey:
Yeah, I can do that.
Thanks everyone!
Regards,
Scott
>> get a doorbell transformer.
> A great idea, but not the most cost-effective.
I thought you were seeking long-term reliability. Doorbell transformers typically last decades.
Driving is a drawback (tho H-D has ship-to-home at some Free threshold you might reach with a few more toys), but if you prefer buying $8 warts every few years instead of a $18 lump once, do it.
> A great idea, but not the most cost-effective.
I thought you were seeking long-term reliability. Doorbell transformers typically last decades.
Driving is a drawback (tho H-D has ship-to-home at some Free threshold you might reach with a few more toys), but if you prefer buying $8 warts every few years instead of a $18 lump once, do it.
PRR:
You may be right, but other than the issues I've been experiencing with Schiit's wall warts, I've never had a problem with a brick. I'm prepared to run the risk that my $8 purchase (the need for which might never arise if Schiit's latest wall wart doesn't crap out like its predecessors) will continue in that vein. If I do buy the brick and if it does fail, then I will absolutely consider making the grand purchase of a doorbell transformer.
Thanks to everyone!
Regards,
Scott
You may be right, but other than the issues I've been experiencing with Schiit's wall warts, I've never had a problem with a brick. I'm prepared to run the risk that my $8 purchase (the need for which might never arise if Schiit's latest wall wart doesn't crap out like its predecessors) will continue in that vein. If I do buy the brick and if it does fail, then I will absolutely consider making the grand purchase of a doorbell transformer.
Thanks to everyone!
Regards,
Scott
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