Thanks Mark, I'll look into trying a dozen different ways once I can turn on my ACP+ for more than a second at a time.
Thanks Ferule for sharing your experience, or I would have really gone into a panic attack tonight.
I just fired up the ACP+ and got a thump-thump-thump sound on the headphones, like if I had created a small pulsating machine. Led was blinking on/off, voltage across R4 where almost reaching value, and then dropping back to 0.8V.
Having already read your experience, I swapped the Kit's poser supply with the ACA v1 I have (19v/4A) and, voilá, I have lovely music playing on both ears.
Now, I am a bit screwed, as I don't have any other 24V PSU (I'm not about to phase my ACA out of service to put in the ACP+
).
So, I'm a bit stuck. I'm surprised no one else has shared this issue with the parts Kit? Is everyone just replacing the brick and are happy with that? Is this an edge case and only happens to some of us?
I'm using full stock parts Kit, no replacements whatsoever!
Any recommendations as to something that could actually fool the PSU to not "reset" itself after every second?
Thanks in advance,
Rafa.
Thanks Ferule for sharing your experience, or I would have really gone into a panic attack tonight.
I just fired up the ACP+ and got a thump-thump-thump sound on the headphones, like if I had created a small pulsating machine. Led was blinking on/off, voltage across R4 where almost reaching value, and then dropping back to 0.8V.
Having already read your experience, I swapped the Kit's poser supply with the ACA v1 I have (19v/4A) and, voilá, I have lovely music playing on both ears.
Now, I am a bit screwed, as I don't have any other 24V PSU (I'm not about to phase my ACA out of service to put in the ACP+
).So, I'm a bit stuck. I'm surprised no one else has shared this issue with the parts Kit? Is everyone just replacing the brick and are happy with that? Is this an edge case and only happens to some of us?
I'm using full stock parts Kit, no replacements whatsoever!
Any recommendations as to something that could actually fool the PSU to not "reset" itself after every second?
Thanks in advance,
Rafa.
Sorry, I see it's not isolated. Is it happening to everyone? Well, at least I'm glad it's not something I did wrong
Rafa.
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If you have the ‘pulsing problem’ with the little Triad switching supply then you might try a simple experiment. Thoroughly clean the area on the PCB around the gate pins of the four MOSFET’s with a good flux remover . On both sides of the PCB. When it is clean and dry try it again.
[edit] and the gate traces....
[edit] and the gate traces....
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We are receiving a number of reports of this behavior on the kit and the culprit appears to the the wall-wart SMPS we included. We chose these as they are over-specced for the needs of the circuit and were pretty inexpensive compared to the Triads Nelson specified in his article. Unfortunately some do not appear to function as specified and are resulting in what you are seeing above - pulsing of the LED and failure of the circuit to come on in a steady state. This is actually the result of the wall-wart's short-circuit/overload failure mode, so its saw-toothing from on to off but not charging the input filter caps and so will never actually come on.
If you are having issues as above, please contact me directly and I will arrange to get you a replacement. We are halting orders of the kit from the store and will be shipping replacements to the store that will be included with the kits. In the meantime, if you have one of the Triads or Meanwells that have been used on previous kits that have a rating of 24vdc at 500ma or greater, you should be able to build the circuit and get going.
Apologies for the inconvenience.
--Tom
Thanks Mark, I'll look into trying a dozen different ways once I can turn on my ACP+ for more than a second at a time.
Thanks Ferule for sharing your experience, or I would have really gone into a panic attack tonight.
I just fired up the ACP+ and got a thump-thump-thump sound on the headphones, like if I had created a small pulsating machine. Led was blinking on/off, voltage across R4 where almost reaching value, and then dropping back to 0.8V.
Having already read your experience, I swapped the Kit's poser supply with the ACA v1 I have (19v/4A) and, voilá, I have lovely music playing on both ears.
Now, I am a bit screwed, as I don't have any other 24V PSU (I'm not about to phase my ACA out of service to put in the ACP+
So, I'm a bit stuck. I'm surprised no one else has shared this issue with the parts Kit? Is everyone just replacing the brick and are happy with that? Is this an edge case and only happens to some of us?
I'm using full stock parts Kit, no replacements whatsoever!
Any recommendations as to something that could actually fool the PSU to not "reset" itself after every second?
Thanks in advance,
Rafa.
For folks having this issue, this is the replacement part:
https://www.mouser.com/ProductDetai...Xug2SrKLjywUhVorSrdHIlAf8cdIwPRBoC0gsQAvD_BwE
Contact me directly/offline and we will work out a swap/replace/credit solution for you for the kit to sort things out for you.
--Tom
Thanks for the quick replies and solutions.
Given how far I am and the time and cost to import another Wallwart, how critical do you guys think it is to have a very “clean” PSU? I can source locally a computer-type brick of 24V and 2A. Will that have a better chance of being “clean” as opposed to the cheap $4 wallwarts I can find locally (risking that they behave the same!).
If the PSU filter enough to clean a noisy PSU should I happen to buy the usual crap that I can source locally?
Thanks for any feedback,
Rafa.
Given how far I am and the time and cost to import another Wallwart, how critical do you guys think it is to have a very “clean” PSU? I can source locally a computer-type brick of 24V and 2A. Will that have a better chance of being “clean” as opposed to the cheap $4 wallwarts I can find locally (risking that they behave the same!).
If the PSU filter enough to clean a noisy PSU should I happen to buy the usual crap that I can source locally?
Thanks for any feedback,
Rafa.
The issue isn't current, the issue is how much load capacitance the wall wart can tolerate at turn-on. Bigger current ratings don't automatically go hand-in-hand with higher load capacitance specs.
ACP+ puts a lot of load capacitance on the SMPS. As you have painfully discovered, some SMPS can handle this gracefully and others cannot. UNfortunately, very few SMPS sellers are willing to write a max-load-capacitance spec on their datasheet, and then accept customer returns of units that fail this spec. Just for fun, search Mouser and DigiKey and Element14 for wall warts that have the right voltage and current for an ACP+. Then check whether their datasheets give a max load cap specification. Maybe you'll get lucky (?)
ACP+ puts a lot of load capacitance on the SMPS. As you have painfully discovered, some SMPS can handle this gracefully and others cannot. UNfortunately, very few SMPS sellers are willing to write a max-load-capacitance spec on their datasheet, and then accept customer returns of units that fail this spec. Just for fun, search Mouser and DigiKey and Element14 for wall warts that have the right voltage and current for an ACP+. Then check whether their datasheets give a max load cap specification. Maybe you'll get lucky (?)
You all should know the power jack spec'd ( DIGIKEY CP-037B-ND) in the B.O.M. does not fit that power supply. You need 037A, not B.
If you look at the Triad specs, I don't see them here anywhere or on the individual data sheets:
https://www.mouser.com/catalog/specsheets/WSU-Series datasheet.pdf
I randomly looked up an open-frame Meanwell and looked at its datasheet here and found nothing too:
https://www.meanwell.com/Upload/PDF/NES-350/NES-350-SPEC.PDF
These are both high-quality SMPSs but they do not list these specs here. Do they put them elsewhere or are they computed or just missing? Just trying to understand where to find these and I am sure others are too.
Thanks,
--Tom
That's the problem. You probably won't find a spec like that. Parts substitutions should be qualified with some pre sales beta testing to make sure everything works properly together. Certainly not complaining about the diyaudio store kit offerings. Just an observation. We have a program at work that's highly encouraged to take advantage of called "Lessons Learned" as a continuous improvement strategy.
The only SMPS datasheets that include a max load capacitance spec, at least the only ones I remember, were non-wall-wart, metal boxed, open frame supplies from higher-end suppliers like CUI. Here is one which does include that spec: LINK . . . . but it's not a wall wart.
My own guess, born of ignorance, is that max-C may not be a tightly controlled parameter; each individual SMPS unit that rolls off the assembly line may have a very different max-C-that-can-be-tolerated-at-startup. The manufacturer doesn't want to test for it and SURE doesn't want to reject products that pass all other tests but fail this spec. That's just wild speculation from an uninformed hobbyist who has never set foot in a SMPS factory.
SMPS buyers could of course hook up various load capacitors, then observe how much Cload is needed to make a certain SMPS sputter and fail. Then divide (Biggest Cload That Still Works) by a factor of 3 (for safety) and declare: Wart-XYZ can only be used with a Cload less than So-and-so. Hopefully the 3x safety factor covers unit-to-unit variability, temperature variability, mains voltage variability, component aging, and all other oogah boogah scary monsters.
My own guess, born of ignorance, is that max-C may not be a tightly controlled parameter; each individual SMPS unit that rolls off the assembly line may have a very different max-C-that-can-be-tolerated-at-startup. The manufacturer doesn't want to test for it and SURE doesn't want to reject products that pass all other tests but fail this spec. That's just wild speculation from an uninformed hobbyist who has never set foot in a SMPS factory.
SMPS buyers could of course hook up various load capacitors, then observe how much Cload is needed to make a certain SMPS sputter and fail. Then divide (Biggest Cload That Still Works) by a factor of 3 (for safety) and declare: Wart-XYZ can only be used with a Cload less than So-and-so. Hopefully the 3x safety factor covers unit-to-unit variability, temperature variability, mains voltage variability, component aging, and all other oogah boogah scary monsters.
Completed the kit yesterday. Had the pulsing LED so popped in another 24V brick and all good. The amp has replaced a passive pre and an O2 headphone amp. Partnered with an old F5 it sounds simply gorgeous!!
The kit is great value for money and so convenient. I probably spent more work time on the case than on the board, maybe a custom case would add to the kits appeal?
The kit is great value for money and so convenient. I probably spent more work time on the case than on the board, maybe a custom case would add to the kits appeal?
