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226akamark
Posted on Thursday, October 30, 2003 - 4:17 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I have here a LDO (Long Distance Operator) base amplifier. It has 4 - 8950 tubes, 1 driving 3. Anyone know what the output should be? Haven't checked to see what tube conditions are in, all I know is no output, and buzzin' in amp. Light and tubes light up, fan goes on, but no output. Considering have it put in shop, think it would be worth it? Thanx for any comments or suggestions.
Mark / 226
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Kc0gxz
Posted on Thursday, October 30, 2003 - 11:34 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

226akamark

If it needs new tubes, good luck in finding them. The CAN be had but they are VERY expensive now since that aren't made any more.

Jeff, kc0gxz.
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Crafter
Posted on Friday, October 31, 2003 - 2:45 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Same amp basically as a palomar skipper 300. Usually 250 to 300 watts. Dont drive it.
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226akamark
Posted on Friday, October 31, 2003 - 9:28 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Ok, thanx guys. I'm going to have the tubes tested next time I'm up in a town where they have a tester. This little 2-horse town is about 50 miles away from anyone that has one, but they do specialize in repairing old tube amps. I read an article that the tubes could be changed to the el509/el519 with some work. Might be something to consider if I really am interested in getting it repaired. Oh yeah, Crafter. I think that is the problem about over driving it. Back when I knew even less than i do know, I hooked up my 2970. I use to think the more in, the more out. Some have to learn the hard way.
73's
Mark / 226
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226akamark
Posted on Friday, November 28, 2003 - 8:03 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hi all,
Took me long enough to get back on here, but the thing is up and going again. For one exception, the preamp. Save that on for another day. Thanx to Joe for sending me the schematic on this thing I found the right value resistor that was burned.
Anyway I would like to know A good input wattage to use on an old amp like this one. And if anyone think the 4 watt dead key, and 12 watt PEP on sideband is too much for it.
I'm using a 142 GTL, and as far as I can see there's been no limiter that's been clipped or anything. Just a channel conversion, and sliding clarifier conversion. Only says about 80% modulation.
Thanx for your input, 226 / Mark
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Bigbob
Posted on Friday, November 28, 2003 - 1:40 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Don't go over that or poof,also back your dead key to 2 watts,less heating of the driver tube,let your swing do the driving.Bigbob
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226akamark
Posted on Friday, November 28, 2003 - 5:01 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Alright Bigbob,

Got it at 3 watts now, because my swr meter don't work in my 142 with any less than that. I'll back it down though. Did notice a little squeel in it lately now and then tuning it in, don't know if it's in the jumpers or what. Guess I got some more switchin' around to do for now. Thanx for your opinion though, it's much appreciated. 73's, 226 / Mark

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