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Palomar 300a question?

R

radioman24

Active Member
Jul 19, 2009
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34
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okay i knew a local radio operator who ran a palomar 300a base amp the case was chrome and the amp had to be driven hard he would use a rci 2990 to drive it and on am it would peak at 900 watts on on ssb almost 1200 watts, any idea what tubes would be in this amp? also ever see these amps on ebay or anywhere else for sale?

Dan
 

radioman24 said:
okay i knew a local radio operator who ran a palomar 300a base amp the case was chrome and the amp had to be driven hard he would use a rci 2990 to drive it and on am it would peak at 900 watts on on ssb almost 1200 watts, any idea what tubes would be in this amp? also ever see these amps on ebay or anywhere else for sale?

Dan
Click to expand...

6lq6,6kd6,6lf6,8950

Old tubes,a little expensive nowdays :cry:
 
I suppose you could drive one hard if you wanted to, but it's not a requirement. In the high position you can drive one with up to 10 watts. In the Low position you can drive it with up to 100 watts. Those wattage numbers seem a bit exaggerated to me. I have one sitting here if you're interested. It functions 100% and will put out an honest 350-400 watts PEP. The fan is a bit noisy when you first turn it on, but that's pretty common with these older amps. PM me of you're interested in it...
 
i've had a couple of 300a s over the years and never saw numbers like that.guess he has some magical tubes in it ...I don't think he getting that many watts from that amp..he must be seeing a lot of dirty rf messing with his meter
 
Out of a chrome top 300A, new 6LF6s, I could get 750 easy. 1000-1100 if I drove the living shit out of it.

That was when I could go to Thrifty's and get tubes..... When they ran out, I started doing the Radio Shack thing, they where in the same strip mall..... And they replaced them for free until they caught on to getting raped for sweep tubes that way.

To see those numbers, you need to drive it with 45-60 watts on high power... Yeah, hit those first two tubes with half of their output power.

As soon as tube supplies dried up, and the tubes hit 10 bucks a piece, I hit the amp with a radio only. I also replaced 1 power transformer in it, and upon that, drilled vent holes on the bottom of the case (a mesh), put LARGE feet on it and put a 5 inch fan on the top drawing air out.


Want to hear something even more crazy? I knew a guy that drove a Messenger AM30 (45 watt modulator) into a PAL 350MDX (1X8950 into 3X8950s) on low into a PAL 350MDX on HIGH...! Yup. Hitting a single 8550 with 45 watts wasn't enough, he hit a single one with about 600. This was Sodbuster in the 80s, in San Diego. With a Cobra 2000 in his El Camino. Loud, yup. RF Parts LOVED him, new tubes about weekly.


--Toll_Free
 
That was when I could go to Thrifty's and get tubes.....
Click to expand...

Hahaha....Ya I remember those days, the great big tube center just to left of the door, big console tester on top with a whole tube cabinet below just stock full of every kind of tube you wanted....
I used to run a 300A with a JB 12 in front of it and even that was not healthy for it....and great tip on the fan for the external supply....they should have at least drilled hole in the thing top and bottom.
They were great to sit a cup of coffee on stayed warm that way....

73
Jeff
 
Wow...I would never try to push one that hard...especially now days with the price of tubes...lol. I pushed mine to 400 watts right after I got it just to see if it would do what the paperwork said it would. I rarely run it, but when I do I only push it to around 200 - 225 watts. Most of the time I have no problem making a contact with just the radio so it just sits there idling and keeping the radio room warm. :D
 
what would you sell your palomar 300A for ? would it just hook up to a yaesu ft 747 used as a base station with the HD yaesu power supply? Just curious and would it really splatter or does it have the ab bias circuit?thanks and just wishful Xmas shopping

Oil2Gas
 

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