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300a power supply's for sale?


There are two different models and the only way to know which one your amplifier needs is to look inside at the rectifier. One uses a two leg voltage doubler and the other uses a full wave bridge. Plug the wrong transformer in and you'll either have half the needed plate voltage, or worse yet, double! This information is something I learned from NomadRadio in another thread.
 
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Yes I am waiting for it to arrive. To see which one it requires.i read you can change which power supply the amp can use. It's getting rebuilt when I get it. I was just seeing if any are out there (power supply)
 
Way too often, a 300A found in a house cleanout or estate basement sale looks like it has some value, and gets sold. Has a power cord, so it must be the whole unit, right?

The transformer is unmarked, heavy and gets ditched with other hard-to-identify trash before anyone can object.

How many times does the amplifier change hands before someone asks "where is the rest of it?"

But lost power supplies are the rule. Much more rare that a shiny RF deck gets thrown away, and the black unmarked transformer makes it to market.

Gotta wonder what's the proportion between surviving RF decks and transformers. Two amps for every one transformer?

Three?

Got me wondering if this doesn't provide a use for old 350Z amplifiers. Find a box, make a cable with the Jones plug and put the transformer from the 350Z in it.

You would have to change the HV circuit in the RF deck to a bridge rectifier. The doubler circuit seems to be the more-common setup we see in the RF deck.

But finally, something the 350Z is good for, maybe? As an organ donor.

73
 
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I dont have the amp yet. Not sure why I bought it. Crazy i guess. But finding a power transformer might keep busy so i dont buy another broken amp. And I still have the other four to fix. Need to quit buying for a while.
 
Way too often, a 300A found in a house cleanout or estate basement sale looks like it has some value, and gets sold. Has a power cord, so it must be the whole unit, right?

The transformer is unmarked, heavy and gets ditched with other hard-to-identify trash before anyone can object.

How many times does the amplifier change hands before someone asks "where is the rest of it?"

But lost power supplies are the rule. Much more rare that a shiny RF deck gets thrown away, and the black unmarked transformer makes it to market.

Gotta wonder what's the proportion between surviving RF decks and transformers. Two amps for every one transformer?

Three?

Got me wondering if this doesn't provide a use for old 350Z amplifiers. Find a box, make a cable with the Jones plug and put the transformer from the 350Z in it.

You would have to change the HV circuit in the RF deck to a bridge rectifier. The doubler circuit seems to be the more-common setup we see in the RF deck.

But finally, something the 350Z is good for, maybe? As an organ donor.

73
 
I think that's all that is in that box I have another 300a with the supply. I'm going to look inside it. Thanks.
 
300 Volts is a bit too hot. I explained the math in another post just now.

Each 6.3-Volt heater draws just under 3 Amps. Put six of them in parallel and you need 18 Amps.

Pretty sure this is why Palomar wired them as three series pairs. Cuts the current demand for the heaters down to 9 Amps.

For Antek's transformers, I really prefer the grid view of all their toroid transformers.

[URL]http://www.antekinc.com/grids/[/url]

There is a big gap around the voltage needed for every size over 300 VA. Since John's ratings are for 50 Hz, you can pull another 20% more power from them at 60 Hz. You can comfortably round this off to 400 Watts from his "300VA" part.

Only viable choice I see is this one: [URL]http://www.antekinc.com/as-3t275-300va-275v-transformer/[/url]

A 40 bucks plus shipping, that's a reasonable as it gets.

This 100 VA 12-Volt transformer: [URL]http://www.antekinc.com/as-1212-100va-12v-transformer/[/url] should take care of the heater supply. At $21.60 plus shipping, can't see how to go wrong with that.

The two of them together are cheaper than any single transformer would be. But you'll have to fabricate an enclosure and install the cable.

Expensive part, cheap labor to install. Cheap parts take expensive labor to adapt them.

Six of one, half-dozen of the other, pretty much.

Oops. Spoke too soon. Just checked RF Parts and they no longer list the transformer for a six-tube base amplifier. Oops.

They sold that one for years, but not any more.

Oughta look to see if ICA Manufacturing has a cabinet the right size for two Antek toroid parts.

73
 
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It's just that the rf decks are plentiful and cheap without a power supply. Me being a newbie think I can come in and do something you haven't which is find a power supply that works
 

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