New Dual Linear Power Supply

gp4jesus

I may take my cue from from the OP…

This thread reminds me of a similar problem I have w/the DigiTech rack effects device the Studio Quad: heat

The PS looks just like that of a typical laptop/notebook computer. The big diff: 9VAC, 2.2A. The device & PS both separately generate a fair amount of heat. I have two of them in the rack I’ve often wondered if a step down that provides 5+* amperes for both would do the duty w/much less heat. Would the devices run cooler, too?

Thanks for reading this far and any ideas.

Tony

VR3

Yes that is the same one I have, the unit barely is warm running a router and modem

VR3

Plan on upgrading the DC cables though, those are just like 20 awg zip cord in tech flex

heiney9

Running an external HD it does get slightly warm. I think MSG and his math might be correct. This unit might be under what I need at the voltage output. According to his math either one or the other should run safely.

The thing with an external HD is unless it's in use it's not really drawing much power while a router is.

The modem draws less, so I'm going to plug that in alone. Yesterday I just ran the router alone.

I thought maybe I might be able to use this with the EtherREGEN, but looking at the supply that comes with it, it shows 12V @ 4.5A

I guess I have to open my wallet once again.........

treitz3

FWIW - Here are my PS temps...

Zero Zone LPS - 80° - Modem
iFi iPower Elite #1 - 75° - Router/Mesh Mother
iFi iPower Elite #2 - 80° - EtherREGEN
After dark dual LPS with a clock sitting on top 88° - Mesh Satellite/AD clock

Tom

heiney9

Dr. Hardy might be onto something. I have been looking under the hood and I don't see a voltage regulator from the top view (mounted on top). If you look at this photo in the center towards the rear (where the pcb is cut out for the IEC) you'll see a screw and what looks like heat sink tape. I think the voltage regulator is using the case as a heat sink. There are 3 legs that come from underneath and are soldered to the pcb.

Running the external HD the transformer is a bit more than warm, but the lower part of the case is much warmer. I think the heat is coming from using the case as a heat sink for the voltage regulator.



H9

heiney9

treitz3 wrote: »

FWIW - Here are my PS temps...

Zero Zone LPS - 80° - Modem
iFi iPower Elite #1 - 75° - Router/Mesh Mother
iFi iPower Elite #2 - 80° - EtherREGEN
After dark dual LPS with a clock sitting on top 88° - Mesh Satellite/AD clock

Tom

My brother has one of those hand held temperature guns. I'll have to borrow it to see what the actual temp is.

H9

heiney9

Running the part number it's a P channel Vishay power MOSFET (IRF9Z34).

The lower part of the case is getting just as hot as when I ran the router alone. Both walwarts are 12V 2A.

I'm going to run the modem by itself and see. Walwart is 12V 750mA.

H9

P.s. it appears that maybe the case is designed to get hot as a heatsink for the power MOSFET.

treitz3

That MOSFET has an operating temp of 175°C or 347°F and they are designed to be mounted to a heat sink/case, so this would most definitely explain the higher operating temps.

Tom

heiney9

The temp just running the Modem is closer to what I would consider normal even though the case is much warmer (because it's a heatsink for the power MOSFET).

I guess I saw the 3.5A/25W rating but didn't consider that wasn't at 12V. While it might run both fine for awhile, I feel like long term it's not a good fit and I would constantly worry when not at home if the draw was too much for this particular LPS.

I guess I'll put this one in the audio closet for now and may be find a use for it later

Thanks to @msg for doing the math..........I think it was correct.

I'll probably get the Tera Dak that Trey is using.

I was going to get this, but I think it's overkill and cost prohibitive compared to the Tera Dak. I may get one in the future to run the Node and ER




https://power-holdings-inc.com/Keces-P6-6-Amp-Linear-Power-Supply-p485459710

H9

msg

heiney9 wrote: »

I guess I saw the 3.5A/25W rating but didn't consider that wasn't at 12V.

Thanks to @msg for doing the math...

I'll probably get the Tera Dak that Trey is using.

H9

I wouldn't have known, either, that the available current varied with each voltage model had I not seen it in one of the other listings. They really should have had a chart to show what you can do with each model.

China's next operation: Destroy the US from within, burning down homes, one audiophile at a time.

heiney9

I do think it is designed to run warm to hot since they are using the case as a heatsink. But with both plugged in I personally felt it was too hot. I've been running just the modem off it all afternoon and the case and transformer are warm, but not hot like when running the router alone.

H9

SCompRacer

I have a 5v PS of similar design that I power an FMC (fiber media converter) with.

msg

heiney9 wrote: »

I do think it is designed to run warm to hot since they are using the case as a heatsink. But with both plugged in I personally felt it was too hot. I've been running just the modem off it all afternoon and the case and transformer are warm, but not hot like when running the router alone.

H9

I wouldn't be comfortable with that, either, without more info. I don't know, maybe contact the seller for the 12v max current output?

Once confirmed not overdriving, could always add some heat management. CPU heatsink and fan would prob work, mounted right to the case. Or go the drilled holes route, open up a couple of 3/8 intake holes on the sides of the cooler end, with a few more on top over the hottest area, and then lay a 120mm exhaust fan on it, like something from AC Infinity, with some sorbothane pads?

Prop it up on some taller feet, maybe, to give it some more room to radiate?

Gardenstater

An inexpensive Kill-A-Watt type device would be helpful to confirm actual power usage from the wall outlet.

heiney9

SCompRacer wrote: »

I have a 5v PS of similar design that I power an FMC (fiber media converter) with.

Looks identical. How warm does it run?

H9

mhardy6647

My opinions (but not arbitrary ones!), FWIW: The idea of a heat sink is to spread a large amount of thermal radiation over a large and very thermally conductive surface area to get it away from the component(s) generating the heat! In other words, a good heat sink (adequate in size, geometry, and thermal properties) will get warm if it is doing its job. If it is hot, it's either under-sized, poorly designed, "defective" (e.g., no or inadequately thermally conductive paste between heat-generating components and the heat sink), or too much heat is being generated by a component.

Any of those is possible, but circumstantial evidence does seem to suggest more is being asked of the P/S than it can comfortably provide (a la @msg's assessment).

SCompRacer

heiney9 wrote: »

Looks identical. How warm does it run?

H9

Barely warm as I'm only using .5A of its 5v 3A capacity. You can see more of the chip they use on this 5v PS while yours is covered.

I was surprised to see they use an IRF9Z34N mosfet in this PS instead of a voltage regulator. Not that its bad. You can use a mosfet in a linear PS, it's just that you usually see mosfets used in amps.

I'd have to google to read more about mosfets used in a PS where I bet @mhardy6647 or @SeleniumFalcon could just explain it.

gp4jesus

HD = hard drive?

I missed this abbreviation’s definition

mhardy6647

gp4jesus wrote: »

HD = hard drive?

I missed this abbreviation’s definition

I think that's what he's talking about in the post(s) above.

MOSFETs? I am guessing they're being used in the same way that a 6L6 is used in a big HV linear P/S like a Lambda (i.e., yes, for voltage regulation). I'd have to google, too, in terms of MOSFETs in a P/S.

I'm outta my depth.


That may be too abstruse A regulator is essentially a feedback loop, adjusting the voltage of the loaded output of the P/S by comparison to a reference voltage. The tube or transistor serves as an amplifier in the loop.

heiney9

I decided last night that I probably misunderstood or they omitted capacity of a 12V draw. Even just running the modem 12V .75A it still was uncomfortably warm for my liking. I couldn't comfortably go to bed or leave the house without constantly thinking about it. It may be designed to run just like that, but not to my liking. I'll move on to a higher specd unit. The Tera Dak dual is in my cart. 12V @ 6A each output.

Yes, more explanation about the MOSFET use in place of a rectifier.

H9

Gardenstater

msg wrote: »

Where are you seeing the current draw spec on the unit?

Been a while since I've done these kinds of calcs, but going by those wallwart specs, looks like you might be a little underspecced, which could explain the heat?

W = VA

W = (12v x 1.5A) + (12v x 0.75A)
W = 18VA + 9VA
W = 27VA

And this unit's specced for 25VA, right?

Maybe my maff's off.
I also don't know whether modems and routers run at constant current draw.


There's another similar looking one on Ebay that has this in the description, where they say that 3.5A is the max output current, and that that max output current will vary, depending on the voltage chosen for the unit. There also seems to be some "overhead" required, because these numbers don't match exactly.

Voltage: 5V 7.5V 9V 12V 16V 24V ( if not specified , will ship 12v version by default)

Maximum output power: 25W

Maximum output current: 3.5A (depending on the output voltage, e.g. 24V maximum current is 1A, 5V can reach 3.5A)

They don't spec what the max output current is for the 12V version, but extrapolating based on the note in the above description that only the 5V unit can reach 3.5A and that the 24V can reach only 1A, I'm guessing you don't really have 3.5A to play with, and that you might be overdrawing based on that Wattage calc above.

How does it run with just one device connected?

If each output has a max. capacity of 12.5VA, that 18VA draw is way exceeding the max. permissible value on the one.

SeleniumFalcon

"... MOSFET use in place of a rectifier"

It's probably not being used as a rectifier, there are four diodes in the lower left of your photo for that task (which seem to each have a bypass capacitor paralleled). The MOSFET is probably being used as part of the regulator section, maybe amplifying the difference between the supplied voltage and the desired voltage so the regulator can do its job better. Or, it is most commonly used as a switch. There doesn't seem to be an available schematic so it's difficult to tell.
How about a quiet fan to keep it cool (most bench power supplies have a fan)?

mhardy6647

FWIW, I would presume @SeleniumFalcon's first "hunch" is correct and that the MOSFET is probably in the feedback loop for regulating the output voltage depending on the load requirements.

In this small* Lambda HV DC P/S, you can see two of the four 6L6 that serve that role for its regulation. 200 VDC at 200 mA. That'll kill ya.



________________
* It is a small Lambda both in terms of its power output and that I can actually lift it by myself. I bought it years ago because the price was less than the four 6L6s in it were worth. The third tube visible in the photo above is one of the 5U4 HV rectifiers in that P/S.

gp4jesus

So HD does mean hard drive?

msg

Hey, Tony. Yeap.

heiney9

I pretty much decided that the BRZ HiFi unit works as intended, it just gets too warm for my comfort. This is by design apparently and not a flaw.

I was going to go with the TeraDak dual 12V 6A unit new (or used if I could ever find one) $300 plus seemed a bit much for running a modem and router. Atleast at the very top of what I felt was necessary to spend.

I missed buying a Keces DC-116 dual 12V 6A regulated PS awhile back. That's the one I've really wanted or it's successor the P3.

One came up used from the guy I just bought an UpTone USB REGen. He lives in Chicago so shipping was a day. He cut me a good deal.

This is what I'm about to fire up and use for a LPS for my router and modem. I did also purchase (2) iFi - iPower Silent power 12V - 1.8A adapter style since they get good reviews, but ultimately I think the Keces will be better. I never even had a chance to take the iFi's out of the boxes...lol.







The Keces P3, the DC-116's successor expands on the design and is a bit beefier. The current P6 is similar to the P3, but the prices increased a lot during/right after COVID. A new P6 will set you back $549.

I think will be a nice addition and make things very silent.

H9

VR3

Looks beefy! Should perform!

heiney9

This thing has a lot of reserves. I shut it off with the multi-meter hooked up and it took almost a minute after I turned it off for it drain.

Also, I know these can be configured for multiple voltages. The factory sets a range based on the customer order and if you look, there are (2) sets of blue trim pots and a toggle switch for each output. There is an LED on either side of the trim pots. Depending on where the toggle is set the LED lights up next to the trim pot associated to that voltage setting. For fine tuning. Pretty cool.

The one output is either 5V or 12V the other output is either 12V or 15V based on the position of each toggle switch (and my voltage meter readings). Customers could order different variations, but only (2) different voltage selections for each output. The newer P3 offers even more settings.



This can now function as an LPS for the Node 3 and also for the EtherRegen in the main rig. 2 birds one stone.

I also bought (2) iFi power supplies. I think I will now run those with the router and modem and the Keces DC-116 for the Node3 and EtherRegen.

Win/Win and no more money spent....lol

Anyway, this allows me a whole lot more flexibility. I just have been thinking this LPS is overkill for the modem and router?????

H9

heiney9

Also I need to add, there is a chart on the back of the unit with an LED color and the voltage that matches. The LEDs on the inside are what that chart is for. The LED's near the output jacks don't change color when you flip the toggle switch.