Amplifier Power Req's.

[thedood]

Can anyone suggest if a 20 amp PSU will be enough to run the average 250 watt amp? What does it mean when someone refers to an amp as a 2 pill or 6 pill? Thanks!

[Deleted User 14541]

Pill is a slang term for transistor...usually a 2sc2879. A 2 pill has 2 transistors. A 20 amp supply might run a 250 watt amp if the PS rating is conservative...not all power supplies live up to their rating and some will exceed it. If you already have the 20 amp supply it wont hurt to try but if you're buying one I'd go at least 30 amps. If you plan to run a radio on it too go a little bigger.

[thedood]

Thanks for the reply. I already have the psu. Its a pyramid. I also have a 12 amp pyramid I use to power my radio. Would prefer at this point not to buy another psu because I want to make some antenna improvements which are going to be kind of costly.

[MDYoungblood]

A Pyramid 20 amp probably does 12 to 15 amps continuous. A 20 amp is marginal to say the least, even on low power, you will be able to tell if the amp chatters on transmit, if so just don't use it and get a bigger supply, you can find 50 amp supplies for a good price these days. Like 543 said, any RF transistor is nicknamed a "pill".

3's

Greg

[thedood]

MDYoungblood thanks for the info.

[Deleted User 14541]

Keep an eye on the power supply temperature. It may run hot under heavy load.

[Crusher]

That 20A supply will power a 1 pill nicely. Even a pyramid 35a supply is barely enough for a small 2 pill. Not to mention it has a very low duty cycle. For the 2 pill, pick yourself up one of the megawatt power supplies and done. Can be had for about $60. Will hold a 2 pill with 2879's nicely. The 400 version of the megawatt or similar. You will be happy

[kskev]

That 20A supply will power a 1 pill nicely. Even a pyramid 35a supply is barely enough for a small 2 pill. Not to mention it has a very low duty cycle. For the 2 pill, pick yourself up one of the megawatt power supplies and done. Can be had for about $60. Will hold a 2 pill with 2879's nicely. The 400 version of the megawatt or similar. You will be happy

Hey all, as I was reading this thread, I too may have a too small of a power supply for my DX 250 HDV linear amp!
I have a Yaesu power supply model FP-1023 which puts out 13.8V @ 23A continuous with a 25A limit.
So.... guess that's a little shy of what I really need to run this DX 250??
Crusher suggested a 400 version of the megawatt or similar.
Is this what is being talked about....

S-400-12
36 amps 41 amp peak
13.8 VDC
$60.00

So my question from everyone is for $60 I think this a possible best rout to go, or will the current power supply be ok?
What do you all think?
Thanks all!!!!

[1206FL]

No the current supply will not be enough. Get the megawatt s400. Save your yaseu power supply for a 100 watt radio. JMO.

[kskev]

Thanks!
Ordered the Megawatt s-400-12 and should be here tomorrow!

[1206FL]

Good deal. You will most likely want to turn the voltage up to 13.8-14.2vdc. Its the orange pot at the left front of the supply. Move slowly and in small increments. Doesn't take much to get it to where you want it. And then enjoy.

[kskev]

Thanks all (Crusher and 1206FL) for the advise in getting the Mega Watt S-400-12, I can tell a difference in running the TS 250 HD,
And 1206 FL, I did put the meter on it and turned it up to 14.0 volts (kind of right in the middle of what you suggested)
NOW, I don't know if you guys are running one of these power supply's, but what does one do with it? I mean it's not like the other power supply I was running had a switch on the front and just flip it on when needed. And having it sit on my desk next to the TS 250.
This power supply comes with an off/on switch in the cord about 12" down from the unit itself.
SO, if you are using one of these power supply, how do you have it set up with your shack?
1) Fabricate a different power switch, closer to the unit itself?
2) Leave it on all the time?
3) Kind of put it behind all the other equipment with a switch to turn it on/off somewhere where its easy to get to?

Its just seams a little awkward having it sit there next to the TS 250 with the wires coming out the front like that and the on/off switch so far down the cord!
God, sorry, just realized I'm rambling ........ sorry! TOO much caffeine today!
Anyways,how do you guys set up one of these Mega Watts in your shack?
Thanks!!!

[1206FL]

I used a small piece of industrial Velcro and mounted the switch for the supply right behind my equipment. Just mount it where it's easy to get to for your setup. Heck I leave my supply running for days without turning it off. I turn off all my equipment and use 6 plug extension cord with fused protection. But if you want to turn the supply off all the time, the Velcro works well. Just get the good stuff made by 3m, the industrial type Velcro. You can even mount it to the supply itself. Hope this helps and glad you like the supply.

[1206FL]

And don't sweat the questions. I did the same thing! Only stupid ones are the ones not asked!

[1206FL]

You can get the Velcro a Walmart or Home Depot. Like I said, get the 3m stuff, it's got good holding capability and the sticky back part is just that, sticky!

[kskev]

Good Idea!
Thanks, Will check into the Velcro!!!

[Crusher]

I upgraded power cord, used SO 12/3. Ran 5 feet from switching supply. Then installed metal box with light switch. Use the nice metal cord feed thrus that have rubber bushing in center. It is a compression fitting/ cord strain relief. Then ran another 4-5' to receptacle. Can turn off and on as you like. I think those cords are a little sub standard. Or you could get fancy. Put in a larger case and install with a toggle switch on from to turn power off and on. Then you could even install volt and current meters if you really wanted to make it fancy. Just run terminals out front or back. If you didn't want to run posts, you could run one of the small 60-75a Anderson disconnects for the low voltage side. Lots of possibilities. Just have to be creative

[kskev]

Thanks Crusher, all good suggestions!

[1206FL]

You are right Crusher the supplied wire isn't very large lol. I am using the s400 and stock wiring, no heat or issues that I am aware of. I don't run anything very long and I am pulling right at 23-25 amps from my Icom 746 at 13.80vdc I do have some larger wire with the plug already on them, just need to make a switch box and get a good switch. Thanks for the info as well Crusher. Hope all is well. I know you been busy!!