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Subaru
1-3-2-4
Premium Member
join:2001-05-31
Greenwich, CT

Subaru

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24VDC power supply 6A

It seems to be impossible to find for a wall wart.. I assume I need a switching power supply?

I'm looking at getting this here and I assume it would run a bit more efficient with a slighty higher voltage?

»www.parts-express.com/pe ··· =320-301

alphapointe
Don't Touch Me
MVM
join:2002-02-10
Columbia, MO

alphapointe

MVM

Check out MPJA.
You're gonna need something like this:
»www.mpja.com/24-Volt-Pow ··· 32%20PS/

24V @ 6+A, you'll never find in a wart/brick (at least not that can actually deliver rated current...)

My guess is that board has a 12VDC regulator on it, and of course input voltage must be higher than the regulator output voltage.

Subaru
1-3-2-4
Premium Member
join:2001-05-31
Greenwich, CT

Subaru

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Those switching power supplies since this is a rather small load do I need a fan? It's going to be going in a wooden box.

mackey
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join:2007-08-20

mackey to Subaru

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Yes, you pretty much need switching. The heat from a linear would probably need active cooling at those power levels...

Finding a brick is gonna be tough due to UL listings and all. The only "barrel" one I found is 20v 6a; everything bigger uses DIN.

I generally get PSUs like this from Jameco as they tend to have a large selection.

20v 6a barrel, $56: »www.jameco.com/webapp/wc ··· 35187_-1
same but with DIN4 plug: »www.jameco.com/webapp/wc ··· 35179_-1

24v 6.67a DIN4, $69: »www.jameco.com/webapp/wc ··· 22212_-1

/M
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

lutful to Subaru

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I think some 24V/10A DIN rail mount power supplies are transformer based. I have used the Meanwell SDR-240-24 in a few projects but that could be SMPS design. Digikey and many industrial automation sites carry them.

alphapointe
Don't Touch Me
MVM
join:2002-02-10
Columbia, MO

alphapointe to Subaru

MVM

to Subaru
said by Subaru:

Those switching power supplies since this is a rather small load do I need a fan? It's going to be going in a wooden box.

Probably not, it won't run hot enough to be a problem. Remember though, your amplifier board is active-cooled, so make sure you allow for that in your enclosure design (you should always allow for airflow whether or cooling is active or passive...)

Subaru
1-3-2-4
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join:2001-05-31
Greenwich, CT

Subaru to mackey

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to mackey
said by mackey:

Yes, you pretty much need switching. The heat from a linear would probably need active cooling at those power levels...

Finding a brick is gonna be tough due to UL listings and all. The only "barrel" one I found is 20v 6a; everything bigger uses DIN.

I generally get PSUs like this from Jameco as they tend to have a large selection.

20v 6a barrel, $56: »www.jameco.com/webapp/wc ··· 35187_-1
same but with DIN4 plug: »www.jameco.com/webapp/wc ··· 35179_-1

24v 6.67a DIN4, $69: »www.jameco.com/webapp/wc ··· 22212_-1

/M

Thanks, in that case I'm better off going with the switching supply, but I thought about the power brick but I would be better off with everything internal and using a IEC320C13 cable for plug in power.

mackey
Premium Member
join:2007-08-20

mackey

Premium Member

Personally I'd spend the extra couple bucks and go with a Mean Well (such as this one) over a no-name knockoff; we have a dozen or so Mean Well's at work and I can't say I've ever had one fail. Whichever one you get, make sure to check the derating curve listed in the datasheet.

/M

Subaru
1-3-2-4
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join:2001-05-31
Greenwich, CT

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to alphapointe
said by alphapointe:

said by Subaru:

Those switching power supplies since this is a rather small load do I need a fan? It's going to be going in a wooden box.

Probably not, it won't run hot enough to be a problem. Remember though, your amplifier board is active-cooled, so make sure you allow for that in your enclosure design (you should always allow for airflow whether or cooling is active or passive...)

The amp is going to have a easy time as it's just for audio for the front height speakers which is really only used in a few parts of movies but yes I will make sure it stays cool, I'm not sure yet how I'm going to cut vent holes.. I was thinking about doing slats.

SmokChsr
Who let the magic smoke out?
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join:2006-03-17
Saint Augustine, FL

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said by Subaru:

I'm looking at getting this here and I assume it would run a bit more efficient with a slighty higher voltage?
»www.parts-express.com/pe ··· =320-301

THD of 10% at spec'd power? Yikes!!!

Subaru
1-3-2-4
Premium Member
join:2001-05-31
Greenwich, CT

Subaru

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bit confusing but I saw this for one of the higher wattage models

"I am sorry about the confusion, the higher the output, the higher the distortion is. To keep the distortion down, just use it at a lower volume.
Age: 35-44
Technical Knowledge: Professional"

My receiver would be controlling the level but out of a 3 hour movie the speakers may only get used for maybe 3 min at the most.. and that's pushing it.

aurgathor
join:2002-12-01
Lynnwood, WA

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Did you look into used laptop power supplies?

Subaru
1-3-2-4
Premium Member
join:2001-05-31
Greenwich, CT

Subaru

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I had a hard time finding the required power output and amps on a laptop power supply.. plus I rather not have a cable snake all over the place, with the switch power supply inside a wooden box I can connect everything internally and wire up the jack for power.
public
join:2002-01-19
Santa Clara, CA

1 recommendation

public to mackey

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to mackey
said by mackey:

Personally I'd spend the extra couple bucks and go with a Mean Well (such as this one) over a no-name knockoff; we have a dozen or so Mean Well's at work and I can't say I've ever had one fail. Whichever one you get, make sure to check the derating curve listed in the datasheet.

MeanWell is Wallmart class crap. Many do not even have pfc front end.
I have several Artesyn 24V/20A 500W with pfc available.

mackey
Premium Member
join:2007-08-20

mackey

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You're joking right? I've purchased no-name power supplies right from China; THOSE were walmart class crap. Mean Well is decent for what they cost and easily 10x better then walmart class crap. Sure you can spend more and get stuff like active PFC, but also offering a budget line does not mean all models are crap. Whether a particular MW model has PFC is listed right there in the specs so you can simply specify that in your search if that's something you need.

I can't say I've heard of Artesyn before. A quick google search only turns up a handful of direct-from-china large order quoting sites...

/M
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

lutful

Premium Member

said by mackey:

Mean Well is decent for what they cost and easily 10x better then walmart class crap.

I have used and recommended MeanWell power supplies and inverters for many years. They are quite OK and Digikey carries them for a good reason.
said by mackey:

I can't say I've heard of Artesyn before.

Artesyn is actually an excellent but premium brand. They compete with companies like Vicor and TDK-Lambda and are targeted mainly at telecom/industrial systems.
public
join:2002-01-19
Santa Clara, CA

1 recommendation

public to mackey

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to mackey
said by mackey:

You're joking right? I've purchased no-name power supplies right from China; THOSE were walmart class crap. Mean Well is decent for what they cost and easily 10x better then walmart class crap. Sure you can spend more and get stuff like active PFC, but also offering a budget line does not mean all models are crap. Whether a particular MW model has PFC is listed right there in the specs so you can simply specify that in your search if that's something you need.

MeanWell IS generic China crap. It may work long enough if you derate it.
Some models are better, but you should not specify any of these for industrial grade products.
public

public to mackey

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said by mackey:

I can't say I've heard of Artesyn before. A quick google search only turns up a handful of direct-from-china large order quoting sites...

Many power conversion vendors including Artesyn were acquired by Emerson Network Power.
public

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said by Subaru:

I had a hard time finding the required power output and amps on a laptop power supply.. plus I rather not have a cable snake all over the place, with the switch power supply inside a wooden box I can connect everything internally and wire up the jack for power.

If you want something small and inexpensive, I also have 12V/6A supplies. Two in series will output 24V/6A, and fit into tight space.

SmokChsr
Who let the magic smoke out?
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join:2006-03-17
Saint Augustine, FL

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Click for full size
TDA 7492 THD spec
said by Subaru:

"I am sorry about the confusion, the higher the output, the higher the distortion is. To keep the distortion down, just use it at a lower volume.

I guess this is revealing as to what is now considered good audio. A Manf that speced a amp to 10% THD would have been laughed out of the industry 20 years ago. 0.5% was one given by the then considered junky amps, with 0.2% being generally considered a decent device. I guess they figure with all the digital crap who would ever notice.

From the Spec sheet that amp would only be rated for 20W in my way of thinking. Looks like the amp is actually only capable of about 23 watts, before it starts clipping. I guess 50W is about when the magic smoke comes out.
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

4 edits

lutful

Premium Member

said by SmokChsr:

... with 0.2% being generally considered a decent device. I guess they figure with all the digital crap who would ever notice.

I actually posted links to several ultra-high performance audio amplifiers (all digital) in that FM tuner thread after you made similar thought provoking comments.

NAD M2 direct digital amp boasts less than .004% THD today. »nadelectronics.com/produ ··· mplifier

FYI 0.005% THD was achieved back in 2006 by a Zetex digital audio amplifier IC. Above THD graph from a good article on DDFA: »www.diodes.com/_files/fr ··· 5508.pdf

Subaru
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Greenwich, CT

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23W watts would blow the speakers off my wall by then

I'm sure you all know what front height speakers are for? That's all I need the amp for.

SmokChsr
Who let the magic smoke out?
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join:2006-03-17
Saint Augustine, FL

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said by lutful:

I actually posted links to several ultra-high performance audio amplifiers (all digital) in that FM tuner thread after you made similar thought provoking comments.

I know... yes, proper digital audio is very very good.. But what's being given is the average consumer is NOT that audio.. It's pure junk. but it has to be great because it's "Digital"

Remember it takes 1.5Mbps to deliver a good stereo audio. The BW just isn't there yet.. mp3's are "digital" but they ain't good audio!
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

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lutful

Premium Member

said by SmokChsr:

I know... yes, proper digital audio is very very good.. Remember it takes 1.5Mbps to deliver a good stereo audio.

You can have even gigabit rate sampling of the analog (or digital) audio input and there are ways to eliminate power supply switching noise by synchronizing the switching and data conversion clocks.

Anyway we can discuss this "digital analog" topic in a new thread some day since it cropped up in a car radio thread and now audio power supply thread.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

1 recommendation

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said by SmokChsr:

I know... yes, proper digital audio is very very good.. But what's being given is the average consumer is NOT that audio.. It's pure junk. but it has to be great because it's "Digital"

Real "proper" audio, in my opinion, requires a 12AT7 in the front end and a couple of 6L6's running push-pull on the back end connected to a nice large output transformer.

Of course if one wanted to run a magnetic cartridge, one might add a 12AX7 to the mix...

Subaru
1-3-2-4
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Greenwich, CT

Subaru

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Anyways we found a source for a 24V 6 A power supply.. thank you
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

54067323 (banned) to lutful

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to lutful
said by lutful:

You can have even gigabit rate sampling of the analog (or digital) audio input

Why would one want to "sample" a digital signal?
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

1 recommendation

lutful

Premium Member

Click for full size
said by 54067323:

said by lutful:

You can have even gigabit rate sampling of the analog (or digital) audio input

Why would one want to "sample" a digital signal?

Two reasons for gigabit rate "over-sampling" of digital audio input ... as explained in specs of a random ($199) audio amplifier from Amazon.

Please argue about this in a dedicated thread.