API Lunchbox P/S - Upgraded at Some Point?

[LunchBoxHero]

I have now read in several places (other forums - the interwebs etc) that there are some incarnations of the API lunchbox (as recent as a year or so ago) that had some "power supply issues" (not my words). No one seems to state that they were specifically defective, but someone said "API was beefing up the Power Supplies on newer lunch-boxes" and similar. Like most rumors there is probably some truth in there (like a specification was changed), but I highly doubt API would release anything with "issues". So...

Does anyone have more insight into this like...

What kind of upgrades?
Was there noise?
Underpowered?
Underpowered with only non VPR units?
Was there a serial number cut off where consumers can know which one they are getting?
Are warranty units eligible for upgrade if one exists?

It would be great if API could step in to clarify this point, but in the meantime, does anyone know? :confused:

If my unit can be upgraded I would love to do so... if these are just false rumors, let's put them to bed!

[LunchBoxHero]

any leads on this question? enquiring minds want to know...

[LunchBoxHero]

another clue, still no one knows??? :confused:

From Chandler website:

IMPORTANT INFORMATION
Little Devil Compatibility with Newer and Older API Lunchboxes

Chandler Limited would like to inform you that we have some updated news concerning the Little Devil compatibility with newer and older API Lunchboxes. Chandler Limited designed the Little Devils to be compatible with the newest version of the API lunchbox. The older API lunchbox version may have insufficient available current. Around 2006-2007, API changed the power transformer in the lunchbox to increase available current.

There are NO compatibility issues with the 10-space API Rack, the newer 6-space API rack or other 500-series racks.

Compatibility Solution With Older API Lunchboxes

If you experience operational difficulties, you can "jump start" an older API lunchbox by turning it on for 3 seconds, off for 3 seconds and then on again. (http://www.chandlerlimited.com/products/little_devil.php)

Can those in the know (I know you're out there) please explain how turning on and off for three seconds could solve a current issue?

Thanks.

[[silent:arts]]

... Can those in the know (I know you're out there) please explain how turning on and off for three seconds could solve a current issue?

I don't know, but one guess:
- turning on a unit always draws more current since all capacitors have to be charged first
- there are voltage regulators shutting down if current is too much
- turning it on for three seconds will charge the capacitors
- turning it off for three seconds isn't enough to discharge the capacitors
- turning it on again you have charged capacitors, the regulator doesn't have the "turning on current problem", doesn't shut down

does this makes sense :confused:

[raf]

You are correct silentarts. It is seeing overload at startup, too many uF equals too much inrush current.

High power SMPS are dirt cheap and small. Only problem designers have is having enough minimum load to stabilize the supply when using oversized PSU modules.

The other issue that you will see with the undersized API power supplies is the fact that they will be noisy as hell if run near their rated wattage.
As much as 150mV of ripple/noise.

On my designs that use SMPS, I use oversized supply modules and "burn off" enough power to satisfy the minimum current consumption using 25 Watt resistors. I see less noise than the best linear supplies doing it this way.
I am seeing aprox 2mV ripple on my SMPS stuff vs 3.5mV using Power One open frame linear power supplies.

[LunchBoxHero]

so is it in general recommended to follow this "3 second on/off" procedure on all lunch-boxes, especially if you have an older one?

[raf]

James

If you have a problem, that can be a temporary workaround. But, you are running very close to the power supply's limit and should be replaced.

You can check a supply by removing all but 1 or 2 modules and see if it stops behaving badly during power up.

> If that solves the problem, the power supply is undersized
> If the problem still occurs you most likely have a defective supply or wiring problem.

rf

[pan60]

so is it in general recommended to follow this "3 second on/off" procedure on all lunch-boxes, especially if you have an older one?


;782']I don't know, but one guess:
- turning on a unit always draws more current since all capacitors have to be charged first
- there are voltage regulators shutting down if current is too much
- turning it on for three seconds will charge the capacitors
- turning it off for three seconds isn't enough to discharge the capacitors
- turning it on again you have charged capacitors, the regulator doesn't have the "turning on current problem", doesn't shut down

does this makes sense :confused:

this is what i understand to be corrected as well.


so is it in general recommended to follow this "3 second on/off" procedure on all lunch-boxes, especially if you have an older one?

as i understand this would only be a issue with the older lunchboxs.



James

If you have a problem, that can be a temporary workaround. But, you are running very close to the power supply's limit and should be replaced.

You can check a supply by removing all but 1 or 2 modules and see if it stops behaving badly during power up.

> If that solves the problem, the power supply is undersized
> If the problem still occurs you most likely have a defective supply or wiring problem.

rf

i would feel the same

If that solves the problem, the power supply is undersized
> If the problem still occurs you most likely have a defective supply or wiring problem.

or possibly a faulty module drawing far to much current for whatever reason?:eek:

[[silent:arts]]

or possibly a faulty module drawing far to much current for whatever reason?:eek:

mhm, Chandler doesn't seam to have luck with their 500 format modules :)
would like to see an open "Devil" - is there a DC/DC converter involved to get higher voltages?

[LunchBoxHero]

just to be clear, I have not so far had any issues with my lunchbox, but it is an older one (2006) and I am often swapping stuff in and out. :eek:

I have been trying to learn about this just because there continues to be so much speculation about the older supplies and I would like to help provide the proper info to the audio community.

I think I will put a call into API, and at a minimum, see if I can get my box upgraded.

If it is just the power transformer and required a simple swap i would get a more substantial one and do it myself, but there is just so little info out there.

With so many new modules coming on the market, I think it is important for folks to know what issues they may have depending on how old their lunchbox is and what they intend to install in it.

[raf]

I think they use SMPS modules...

So, it likely won't just be a simple transformer swap, but a whole PSU swap.

[[silent:arts]]

my lunchbox (bought last christmas) has a standard linear PSU

[raf]

Interesting

I thought API was using SMPS.
Is that an internal supply? (I don't have API, I've got a BAE rack)

[LunchBoxHero]

Yes, the API 6B uses an internal supply.

[tubemooley]

Let's get back to basics for one minute. Clean, stable power is the most important part of an audio system. I don't own an API lunchbox. I have an OSA 11-space box. It came with the OSA power supply. That supply is linear. The power supplies in my Tonelux are switchers. I have an Amek Purepath DIB box with a SMPS built right on the circuit board. Both topologies of power supply will work fine when implemented correctly. The OSA power supply is actually a bit shoddy but it works OK. Anyone selling a box with a power supply should size the power supply correctly for the maximum load it will see. This is engineering common sense. But then the marketing people get involved and start looking to cut cost. And the size of the supply gets cut back to save a few pennies. Now when we're talking about 500-series Lunchboxes...... Things may get complicated. In the Viper Alliance, are there specified limits on power consumption? Or just mechanical spec's to meet? All these manufacturers making modules.... How much current does each one draw? I guarantee it varies widely. If you're selling a Lunchbox with UL and CE certs on the rear, what do you put in it for certification testing? What's the max load it will see? That sounds tricky to me....... That's enough of a rant from me today. My brain just lost track of where it was going. Not looking to ruffle anyone's feathers here. Just trying to help. DW.