Apogee Ensemble SMPS - convert to linear supply?

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pH

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I just bought a second hand Apogee Ensemble Thunderbolt, and aside from having a pretty burned out OLED screen (that I'm about to replace) I've noticed a mechanical high pitched whine from the switching power supply, especially when it's in standby. It uses this unit:

https://www.mouser.com/ProductDetail/Murata-Power-Solutions/MVAD065-12?qs=jTOxOOerCX6KFmD%2FQs4J2Q%3D%3D

It looks like the SMPS only provides a single 12v supply, although I don't quite understand what 'remote sense' is on the pinout diagram?

I'm wondering if there would be any benefit to replacing this supply with an external linear power supply, would it noticeably improve performance? I've heard that these switchers can introduce noise to the audio and can be considered a wear item (hard on capacitors).

Or should I drop another switcher in there and be done with it?
 

scott2000

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pH said:
Or should I drop another switcher in there and be done with it?

Being done is usually good?

I'd maybe be concerned of any tricks Apogee used in other areas to work in tandem with that supply... But Idk....

Maybe some smaller caps on that board have gone bad??
 

Khron

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At least in older units, tantalum caps are known to kick the bucket.

I'd wager "remote sense" has to do with the feedback of the power supply. Instead of using the output voltage on the SMPS board as a source for the feedback (and thus, regulation), the remote sense is used to sense the voltage at the load, in order to compensate for whatever losses might occur in the wiring loom between the two.

"... noticeably improve performance" -  what exact "performance" are you thinking about? Are you noticing any noise in the recorded signals, or on the outputs? If not, don't worry about it. Didn't tape have a humongous noise floor? And that's highly(?) revered... ::)

Apogee tricks? Probably nothing outside enabling the buying in of the simplest form of mains power supply (single-rail, nothing fancy). If the older silver Ensemble Firewire's anything to go by, all the various supply rails are created on the main board. I did a teardown and repair of one on my blog, a bit over a year ago.
 

abbey road d enfer

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pH said:
It looks like the SMPS only provides a single 12v supply, although I don't quite understand what 'remote sense' is on the pinout diagram?
As the name suggests, it takes the measurement of the voltage at the receiver, thus compensating for ohm losses in the wires.

I'm wondering if there would be any benefit to replacing this supply with an external linear power supply, would it noticeably improve performance? I've heard that these switchers can introduce noise to the audio and can be considered a wear item (hard on capacitors).

Or should I drop another switcher in there and be done with it?
Recent smps are far superior to those of 10 years back. I would try to find a Meanwell that fits in teh box.
 

Bo Deadly

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A good SMPS is superior to a linear supply in pretty much every way. You won't fit a linear supply in there and if you did it would probably fry something from the heat. If the existing supply is buzzing, something probably crapped out. Try a new one.

The remote sense pins are supposed to improve regulation in some scenarios. Are they actually used?

EPS-65-12 looks like it's the right size and the mounting holes might even line up. But the connectors are different. I would just buy some female connector housings and pins and re-crimp the wires to match the new supply. Can't get the old one anyway so there's no going back. Or maybe you could get it from the Apogee people but they'd probably charge you 5x the Mouser price.
 

pH

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Thanks for the replies.

Yeah, I was trying to avoid the audiophool-style flameout of starting a switching vs linear discussion but I like having gear that I can easily troubleshoot so that's mostly where I was coming from. But my Seventh Circle rack that has a SMPS has been rock solid and quiet for over a decade while my studio partner's earlier linear supply in his started acting funny, so there's that.

I admit that they seem kind of mysterious and cheesy to me, such a cheap little supply for a supposedly premium unit, but I'll get over it.
 

Khron

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Hey, profits gotta come from SOMEwhere... ::)

pH said:
I admit that they seem kind of mysterious and cheesy to me, such a cheap little supply for a supposedly premium unit but I'll get over it.
 

Bo Deadly

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pH said:
Yeah, I was trying to avoid the audiophool-style flameout of starting a switching vs linear discussion
There are linear holdouts and there is a significant gap in knowledge about how to use SMPS and what ones work well and under what conditions but the SMPS vs linear discussion is pretty much done and SMPS won.

pH said:
I admit that they seem kind of mysterious and cheesy to me, such a cheap little supply for a supposedly premium unit, but I'll get over it.
SMPS are cheap because the parts are not expensive and they're made in large quantities for a variety of different applications. The quality doesn't matter that much to the price. At least for your application a really good one would cost $25 USD at most but I would not be surprised at all of that EPS-65-12 worked perfectly and it's only $14 USD (although you might want to get EPS-65-12-C for $19 and see if the L-bracket and / or cover can be finagled to fit somehow because the metal does act like an electrostatic shield).

Also a follow up note about the sense pins, even if there are wires in the connector for them, you can just leave them disconnected. But there will be supply on one of them so tie those wires off somehow so that they don't short out on each other or anything else.
 

pH

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squarewave said:
There are linear holdouts and there is a significant gap in knowledge about how to use SMPS and what ones work well and under what conditions but the SMPS vs linear discussion is pretty much done and SMPS won.
Good to know, in the end I'd rather not have to drag around an additional breakout brick for the PSU.

Then there's this one, pinout matches so it appears that it would be plug and play:

https://www.mouser.com/ProductDetail/Artesyn-Embedded-Technologies/NPS63-M/?qs=cmdTMbICGPTowtRAetVs5Q%3D%3D

Khron said:
Hey, profits gotta come from SOMEwhere... ::)
Yeah, Apogee service quoted me $69 for a replacement part, that's a pretty tidy profit.
 

Bo Deadly

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pH said:
Good to know, in the end I'd rather not have to drag around an additional breakout brick for the PSU.

Then there's this one, pinout matches so it appears that it would be plug and play:

https://www.mouser.com/ProductDetail/Artesyn-Embedded-Technologies/NPS63-M/?qs=cmdTMbICGPTowtRAetVs5Q%3D%3D
That looks like it could work. But like I said, there's a gap in knowledge about which ones work well. That's one nit-pick with SMPS is that they might not work great because they're sensitive to layout. You just have to try it and then look at the noise floor using your DAW spectrum or whatever tool chain you have for that sort of thing and check to make sure there isn't a low frequency bump somewhere. You might think it shouldn't matter but you want the noise floor to be super flat so that when amplified enough it's just white noise hiss that isn't going to pop out. I have a Motu Traveler mk3 and it's phantom supply has a whistle to it. I don't know what it is but I would be willing to bet it's something about the DC converter making the 48V. The MeanWell SMPS have a good record of success so people around here tend to recommend those. You might think this Artesyn one is better because it's more expensive but that could easily be simply because it's approved for Medical use which has to do more with ground isolation and various certifications and such and not necessarily overall quality.

pH said:
Yeah, Apogee service quoted me $69 for a replacement part, that's a pretty tidy profit.
That's actually not horrible. You should consider that they are going to test that part with the unit and guarantee it's compatibility. That is worth something. Especially if you think you might sell the unit one day. It's an expensive enough piece that you might. Does that price include shipping? They aren't getting rich on $69 replacement parts. They're just covering the expense of the personnel required to go back and fourth with people and pack and ship and such.
 

Ricardus

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abbey road d enfer said:
Recent smps are far superior to those of 10 years back. I would try to find a Meanwell that fits in teh box.

Yup. I've used Meanwell SMPSs and they're very good.
 

Khron

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(Sort of off-topic, with due apologies)

squarewave said:
I have a Motu Traveler mk3 and it's phantom supply has a whistle to it. I don't know what it is but I would be willing to bet it's something about the DC converter making the 48V.

I did a teardown on one (including identifying most of the silicon), a couple years ago, in case it might help?
https://khronscave.blogspot.com/2018/12/34-motu-traveler-mk3-teardown-and-repair.html
 

Bo Deadly

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Khron said:
(Sort of off-topic, with due apologies)

I did a teardown on one (including identifying most of the silicon), a couple years ago, in case it might help?
https://khronscave.blogspot.com/2018/12/34-motu-traveler-mk3-teardown-and-repair.html
Very nice. Thanks.
 

pH

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squarewave said:
You might think this Artesyn one is better because it's more expensive but that could easily be simply because it's approved for Medical use which has to do more with ground isolation and various certifications and such and not necessarily overall quality.
I brought that one up only because of the compatible pinout. A few extra bucks to save me a bit of splicing and also to keep the molex connectors unmodified in case I sell it down the line, for what that's worth.

squarewave said:
Does that price include shipping? They aren't getting rich on $69 replacement parts. They're just covering the expense of the personnel required to go back and fourth with people and pack and ship and such.

I hear ya, it's not exorbitant but that's only for the part to send to me (add another 10 bucks) and put in myself. So I think I'll go with Mouser :)

Nice work Khron on the teardown, what a mess with all that silicone!
 

Khron

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Silicon is the mineral they make semiconductors out of; siliconE is the rubbery material ::)

pH said:
Nice work Khron on the teardown, what a mess with all that silicone!
 
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