 koitsuPremium,MVM
join:2002-07-16
Mountain View, CA
kudos:19 | reply to dellsweig
Re: Undersized Power supplies from Linksys. Do people realise just how much power _FIVE_ amps is? I don't even have full-blown 2U rackmount servers with 6 disks that pull that much.
This sounds like utter nonsense. All one of these tools has to do is purchase a kill-a-watt unit (I have two), hook it up, and run it through tests over a 24-48 hour duration.
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Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer. |
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 dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1
 ·Vonage
| said by koitsu:Do people realise just how much power _FIVE_ amps is? I don't even have full-blown 2U rackmount servers with 6 disks that pull that much. This sounds like utter nonsense. All one of these tools has to do is purchase a kill-a-watt unit (I have two), hook it up, and run it through tests over a 24-48 hour duration. Did you bother to read the thread I refered to??
Have you read the datasheets for the devices being discussed??
Do you undderstand that a devices will DRAW as much power as needed - if the PS only supplies 1 Amp and the chipset needs more - well - I assume you know all this already  |
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| reply to koitsu
The amps being talked about are on the 12VDC side not the 120AC side so they are almost 10 times more than what you measure with a kill-a-watt meter. My guess is that 5 amps is overkill but 1 amp is not quite enough. |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
| said by Automate:The amps being talked about are on the 12VDC side not the 120AC side so they are almost 10 times more than what you measure with a kill-a-watt meter. My guess is that 5 amps is overkill but 1 amp is not quite enough. Exactly |
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| reply to koitsu
said by koitsu:Do people realise just how much power _FIVE_ amps is? Sure, around 30.242 × 10^18 electrons per second. 
It seems high but the supply voltage needs to be considered, at most dellsqeigs router is likely pulling less then 2 amperes of power, or put differently a reasonable 24 watts at most. P(watts) = V(volts) x I(amperes)
If it was drawing 5 amps at 120 volts (which it is not even capable of), he would have a desk sized space heater (and fire) 
said by dellsqeigs :
The before and after views are telling - and as you can see from the dd-wrt thread - others are seeing and quantifying the same. Accton' products (a certain Spanish company resells with the end user agreeing to certain promissory obligations) tend to get very flakey at lower power. In their case it’s not the lack of power, it’s what happens if AC power is briefly interrupted to the adaptor. The DC voltage drops low enough to lock-up the processor, but not low (or long) enough to reset it. The router jams till it is reset.
Linksys is saving a few bucks by using what likely is a lower cost adaptor. As long as the hardware is good (Linksys’ stuff general is), and it will take a 3rd party firmware (Linksys’ versions are poor), I would be happy to spend a few bucks and upgrade the adaptor to really make the router work. |
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koitsuPremium,MVM
join:2002-07-16
Mountain View, CA
kudos:19 | Thanks folks. An EE-savvy friend of mine reminded me of the calculation formulas used for wattage and so on; 12V @ 5A is a heck of a lot less power than 120V @ 5A.
Said friend and I both read the dd-wrt.com thread, and it seems the majority of the focus/reports are coming from people who are intentionally increasing their transmit power way beyond the default scope of the router. For example, the OP is transmitting at the equivalent of 1.2W (yes, 1.2 watts). That's pretty major compared to the default these units come with, pushing ~45-60mW.
Can someone please clarify if this is truly a problem for the WRT* customer base as a whole, or only those who want higher signal strengths?
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer. |
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 Bill_MIBill In MichiganPremium,MVM
join:2001-01-03
Royal Oak, MI
kudos:1
 ·WOW Internet and..
·Comcast
1 edit | Like Koitsu implies, there is much more to it that 1 current rating.
These power bricks are notorious for hype and snake oil, as well as ripple and bad transient response. There's a zillion little measurements in the power supply industry that may or may not be sensitive by the design of the unit (router) itself.
But I don't doubt for an instant Linksys may be using something just "good enough" because of cost. I believe the claims, just not some of the reasons. What may be needed is a *good* 12V@1A power source - not simply more current rating. |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
1 edit | said by Bill_MI:Like Koitsu implies, there is much more to it that 1 current rating. These power bricks are notorious for hype and snake oil, as well as ripple and bad transient response. There's a zillion little measurements in the power supply industry that may or may not be sensitive by the design of the unit (router) itself. But I don't doubt for an instant Linksys may be using something just "good enough" because of cost. I believe the claims, just not some of the reasons. What may be needed is a *good* 12V@1A power source - not simply more current rating. Bill
I did nopt test under stock linky firmware but as I remember, stock linksys sets 28Mw for the transmit power.
Just for grins - I looked at my signal (from my wrt310N) with the stock PS and my 5a PS and compared signal quality, stability and overall data throughput (IPERF) at the 28Mw setting.
With the 5a ps - I got close to 10% improvement in Snr, less noise as well as the same improvement in overall signal strength.
Under the stock PS - I would see IPERF graphs where my data transfer would drop significantly for a second - I assume retransmissions or signal loss. With the 5a PS - I no longer see this.
I know its hard to believe that Linksys would go cheap on the power supply - but I have seen it with my own eyes... |
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Bill_MIBill In MichiganPremium,MVM
join:2001-01-03
Royal Oak, MI
kudos:1 Reviews:
·WOW Internet and..
·Comcast
| Hi Dellsweig, I'm not doubting such tests. What I'd like to know is that same improvement may be realized using a better 12V@1A supply, too.
Actually, I'd love to see that test watching voltage level at the router power connector with an oscilloscope. After all... 12V@1A is 12 watts! |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
| said by Bill_MI:Hi Dellsweig, I'm not doubting such tests. What I'd like to know is that same improvement may be realized using a better 12V@1A supply, too. Actually, I'd love to see that test watching voltage level at the router power connector with an oscilloscope. After all... 12V@1A is 12 watts! Someone on the dd-wrt forums used an analogy to audio speakers - where not enough power causes audio distortion - or clipping. I wonder if we are seeing the same here with the radio carrier??
I dont own a oscilliscope so I cant do that kind of analysis but the analogy makes sense
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Bill_MIBill In MichiganPremium,MVM
join:2001-01-03
Royal Oak, MI
kudos:1 Reviews:
·WOW Internet and..
·Comcast
2 edits | reply to dellsweig
Re: Undersized Power supplies from Linksys. That's not a bad analogy. I don't know what the current demand looks on these routers but under-powered power supplies will coincide current demand with voltage dips. 12V may dip to 9V if it's really bad. "Distortion" means it's not a solid 12VDC. That's what a scope would easily see.
There's also the possibility the 12V@5A supply you're using is supplying more like 13, 14, 15VDC when lightly loaded - but the performance benefit comes with it. I don't know the power distribution but most modern switching power handlers are pretty tolerant over a large voltage range (it may never blow something but I could never say that fact is assured).
Anyone got a DC meter and can get on that voltage may be telling.
EDIT: Dellsweig, is that power supply "heavy"? The picture tells me is is NOT a linear supply with a heavy transformer but a light one which is surely a switcher type. Most are these days. A properly designed switcher type will often have better regulation, too. What about the original?
IRON = heavy transformer = linear supply
Light = switcher = poor design can cause problems but usually better and surely "green". |
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| said by Bill_MI:EDIT: Dellsweig, is that power supply "heavy"? The picture tells me is is NOT a linear supply with a heavy transformer but a light one which is surely a switcher type. Most are these days. A properly designed switcher type will often have better regulation, too. What about the original? IRON = heavy transformer = linear supply Light = switcher = poor design can cause problems but usually better and surely "green". i can tell you the ac adapter that came with my wrt54gl weights practically nothing. if my volt meter didnt die on me a few months ago id be glad to give ya numbers. |
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 peter_mPremium
join:2005-07-13
Canada, QC | Has anyone tried it on a WRT54GL ? |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
| said by peter_m:Has anyone tried it on a WRT54GL ? Just tried my 12V 5A supply on my WRT54GL - G Ap.
Saw a 10% improvement of WLAN to WAN speeds - still not as fast as my WRT310N for the same test.
Saw increase in signal quality and strength - about 10%
During WLAN to LAN IPERF file test - I saw less drops in the graphs - more consistent transfer
I think I will order another one of these for my WRT54GL - nice to see the same type of improvement as I have been seeing with the WRT310N |
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peter_mPremium
join:2005-07-13
Canada, QC
3 edits | Excellent and thank you Dellsweig.
Going from the stock 1 amp to 5 amps sounds a little extreme. Are you able to measure how many amps the WRT54GL is drawing under load?
It might make for a physically smaller and more economical PSU...
Peter |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
| said by peter_m:Excellent and thank you Dellsweig. Going from the stock 1 amp to 5 amps sounds a little extreme. Are you able to measure how many amps the WRT54GL is drawing under load? It might make for a physically smaller and more economical PSU... Peter I am strictly making observations on performance - I would not attempt to give you the electrical details.
As for size - the power blocks linksys (and other vendors) supply are a real pain - they generally dont fit on a power strip. The PS I picked up uses a simple yankee cord to the strip. Also - there is no downside to having sufficient power available - thats not to say that a 2a supply would not be fine - this is just what I purchased. |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
1 edit | reply to peter_m
said by peter_m:Excellent and thank you Dellsweig. Going from the stock 1 amp to 5 amps sounds a little extreme. Are you able to measure how many amps the WRT54GL is drawing under load? It might make for a physically smaller and more economical PSU... Peter Yet another SUCCESS story by upgrading the powersupply
»www.dd-wrt.com/phpBB2/viewtopic.···start=75
This is such a no-brainer - I wonder why EVERYONE isnt running out and doing this?? |
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dellsweigExtreme AerobaticsPremium,MVM
join:2003-12-10
Campbell Hall, NY
kudos:1 Reviews:
·Vonage
| reply to peter_m
said by peter_m:Excellent and thank you Dellsweig. Going from the stock 1 amp to 5 amps sounds a little extreme. Are you able to measure how many amps the WRT54GL is drawing under load? It might make for a physically smaller and more economical PSU... Peter Peter
On the dd-wrt forum - power supply thread
»www.dd-wrt.com/phpBB2/viewtopic.···start=75
There is a graph showing signal and noise at 2A and at 5A
This shows that even 2 amps is not enough
HTH |
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koitsuPremium,MVM
join:2002-07-16
Mountain View, CA
kudos:19 | reply to dellsweig
said by dellsweig:said by peter_m:Excellent and thank you Dellsweig. Going from the stock 1 amp to 5 amps sounds a little extreme. Are you able to measure how many amps the WRT54GL is drawing under load? It might make for a physically smaller and more economical PSU... Peter Yet another SUCCESS story by upgrading the powersupply » www.dd-wrt.com/phpBB2/viewtopic.···start=75This is such a no-brainer - I wonder why EVERYONE isnt running out and doing this?? Because not a single person has taken the effort to bring any of this to light with Cisco/Linksys. Until that happens, most customers are going to take this with a grain of salt.
Someone will need to get in touch with the right folks (specifically engineers) at Cisco/Linksys to discuss it, and have something done about it. If there's no response, keep trying other methods of contact.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer. |
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