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5/28/2020 10:18:12 PM
Posted: 1/8/2003 11:16:30 PM EDT
[Last Edit: 1/8/2003 11:24:40 PM EDT by schapman43]
I'm trying to figure this whole thing out and I dont know all that much about electronics and electricity.  

I have a total of 9 valves that need 24v and draw 1watt when turned on.  I need a power supply that can power them.  My question is this.  Do I need seperate power supply's all at 1amp or can I use 1 power supply that can supply up to 9amp's( preferably with some overhead).

Would this work [url]http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11772&item=3105706714[/url]

What would you suggest for a power supply?

Link Posted: 1/8/2003 11:17:56 PM EDT
[Last Edit: 1/8/2003 11:19:14 PM EDT by 1GUNRUNNER]
Hardwire it directly to the main coming in the panel.

Edit to add: [:D]
Link Posted: 1/8/2003 11:21:28 PM EDT
You can use a single 9 Amp power supply to power all nine tubes at once.  Just fuse the power lead just in case.  24V at 1 Amp is 24 Watts times 9 tubes = 216 Watts.  That's a lot of power.

Notice the shipping on the item.  It's a little expensive compared to the price.z
Link Posted: 1/8/2003 11:22:24 PM EDT
Thanks 1gun but I stay away from anything with that much power [:)]

If it helps any this is what I am going to be running.
Link Posted: 1/8/2003 11:24:04 PM EDT
Sorry guys, that was my bad.  It only draws 1 watt for each valve.  So I need a total of 9 watts.  I'm sure that makes a huge difference.
Link Posted: 1/8/2003 11:27:15 PM EDT
Link Posted: 1/8/2003 11:35:11 PM EDT
Just to make sure I have this correct.  It doesn't matter how many amps the power supply has, I just need to make sure there's enough amperage to power all valves and that its at 24v?
Link Posted: 1/8/2003 11:58:44 PM EDT

That is correct (but not necessarily efficient)

Here are some equations:

Power = Voltage (V or E) x Current (I)
Power = Current(I) Squared x Load/Resistance (R)

Therefore 24volts times 9amps equals 216watts
(just as zoom said before me)

That is what you're going to need.

P.S.- Americans say "Tubes" or "Vacuum Tubes"
     Brits say "valves" [:D] just thought i'd
     throw that in there!

Reminds me of a joke I heard .....
Link Posted: 1/9/2003 12:01:25 AM EDT
Originally Posted By schapman43:
Just to make sure I have this correct.  It doesn't matter how many amps the power supply has, I just need to make sure there's enough amperage to power all valves and that its at 24v?
View Quote

Yes, you need a 24 Volt power supply.  If each valve dissipates 1 Watt of power and you have a total of 9 valves and you may opperate all 9 valves at the same time, then you need a 24V 9W power supply.

Power = Voltage * Current   (for a dc circuit)

So you will only be drawing about 0.090 Amps when all of the valve are opperating at the same time.

The power supply in the ebay link will work, but it's overkill.  You could get by with a much smaller power supply.

Link Posted: 1/9/2003 12:10:58 AM EDT
[Last Edit: 1/9/2003 12:31:01 AM EDT by sr15]
Ok, I tried to provide a couple of links, but they won't copy here for some reason.  I found couple of 24 V power supplies.  If you are interested, go here:


and type in "power supply" in the search block.

Scroll down to power supplies and select "linear" and then refine the search using 24V in the "Voltage Output" parameter (the parameter on the right).
Look for the ones around $35.
If you want an external power supply, go back to the power supplies list and select "external"
There are a couple for about $35 also.

Of course, you could probably just build one for a little cheaper.

Link Posted: 1/9/2003 3:07:36 AM EDT
It's standard procedure to double the power supply in relation to the load. For example, if your load is going to be 9 watts, get [u]at least[/u] an 18 watt power supply. You don't want to choose a PS that can just barely power the load - it will eventually become a smoke supply.
Link Posted: 1/10/2003 12:24:05 AM EDT
Thanks for all the help guys.  I almost thing I know what I'm doing now.  I ended going with this Cherokee supply
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