Author |
Message |
Hotwire
Advanced Member Username: Hotwire
Post Number: 505 Registered: 1-2005
| Posted on Saturday, August 27, 2005 - 11:30 am: |
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Was out at the flea markets and found a good deal for 5 bucks. The Afterburner plus is a mobile linear. It has 2 tubes and all the regular features. Anyone know a little about this amp? It also makes a whining noise when its keyed but all is working OK. When I un key the noise then winds down. |
47nc
New member Username: 47nc
Post Number: 2 Registered: 8-2005
| Posted on Saturday, August 27, 2005 - 2:33 pm: |
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Looks like Hy-Gain makes it do a searc on the web for more info. |
Yankee
Advanced Member Username: Yankee
Post Number: 854 Registered: 7-2003
| Posted on Sunday, August 28, 2005 - 2:56 am: |
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Sounds like it might have an inside fan that might need a little oil, I have only heard of the transistor type of the After Burner Plus. |
Hotwire
Advanced Member Username: Hotwire
Post Number: 513 Registered: 1-2005
| Posted on Sunday, August 28, 2005 - 2:26 pm: |
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Well Yankee I opened it up to dust it out inside and there is no fan. I definatly do use a fan with it though. This sucker REALLY gets hot. I'm just not used to tube amps. Anyway I looked at the 2 tubes inside and they are both printed with RCA 6JU6. Anyone know about these tubes? I tested it on the watt meter and it was around 200 PEP. I really got lucky with the price I paid. As I use the amp the whining sound is slowly getting quieter. The relay was double clicking and found out the mic was causing it for some reason. New mic now. The recieve is very low unless I use the rec amp and that and the stanby switch just needs used.All and all after a good cleanup its a really nice mobile tube amp. Oh and one more thing....it has a label on the back thay says for 6 and 10 meter only. |
Yankee
Advanced Member Username: Yankee
Post Number: 857 Registered: 7-2003
| Posted on Sunday, August 28, 2005 - 4:15 pm: |
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Hotwire, does the amp. have plate and load adjustment controls on it? Could be that the wine is caused by the amp. being mistuned. Keep an eye on the plates of the tubes, you don't want them to be getting red they should glow a blue color when properly tuned. Also if properly tuned it shouldn't get too overly hot, and just like a transistor amp. keep the drive power from the radio down to about 2-3 watts AM. 6JU6s are a good tube, but I would prefer 6146B tubes if the wiring is ok for a pair of matched 6146Bs, try not to get any fingerprints on the tubes. Look around and see if there isn't a smaller driver tube someplace in the amp., most times a 12BY7. Sometimes the driver will be on the underside of the amp. and the finals on top. |
Slowhand
Member Username: Slowhand
Post Number: 63 Registered: 7-2005
| Posted on Sunday, August 28, 2005 - 4:39 pm: |
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The whining noise is the transistors on the back of the amp. They are switching to produde AC so the transformer can produce the HV your tubes need to operate. If it quits whining it'll quit working. |
Hotwire
Advanced Member Username: Hotwire
Post Number: 519 Registered: 1-2005
| Posted on Sunday, August 28, 2005 - 9:47 pm: |
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Thanks Yankee and Slowhand. Yeah yankee the tubes have a redish glow. I may take this amp to a tech, that is if I can find a tech who knows tubes. Still has the whine in there so I hope all is OK. My dad knows a ham tech from the good ol days, hope he is still around. |
Yankee
Advanced Member Username: Yankee
Post Number: 861 Registered: 7-2003
| Posted on Monday, August 29, 2005 - 12:20 am: |
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Hotwire: Something is not right, a redish glow is not good this tells me the amp. is not properly tuned. A redish glow will burn up those 6JU6s in a hurry. Glad to be of help, even though I haven't worked a tube amp. for maybe 20 years or more now, but you don't forget how to run one. My last one had a matched pair of 6146B tubes driven by a 12BY7. |
Hotwire
Advanced Member Username: Hotwire
Post Number: 521 Registered: 1-2005
| Posted on Monday, August 29, 2005 - 9:05 am: |
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Thanks Yankee, After closer inspection its more of an orange glow. Regardless it should be blue I will not use it until I can Have it inspected. Its real hard to find a tube tech around here. Heck its hard to find just a good tech period around here. |
Hotwire
Advanced Member Username: Hotwire
Post Number: 522 Registered: 1-2005
| Posted on Monday, August 29, 2005 - 9:07 am: |
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Oh yeah, I could not find any third tube. |
Slowhand
Member Username: Slowhand
Post Number: 64 Registered: 7-2005
| Posted on Monday, August 29, 2005 - 4:45 pm: |
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On that amp there isn't any plate voltage unless the amp is keyed up. Thats the whining noise, plate voltage being produced. If it whines when it isn't keyed up your keying circuit is messed up. The center of the tubes have to be hot to work. They should be kinda orange. It will only have a blue glow when keyed up. Even then it's sometimes hard to see, so you can't go by that. A lot of older amps used small tubes to energize the relay, usually a 110vdc. People often mistake them for driver tubes. Sounds to me like your amp is working correctly. The tubes have a orange glow in the center, which is correct. It's putting out 200 PEP, thats smoking for that little amp! I'd set it up and run it! |
Yankee
Advanced Member Username: Yankee
Post Number: 862 Registered: 7-2003
| Posted on Tuesday, August 30, 2005 - 4:12 am: |
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Thank you Slowhand. It has been many years since I've messed with a tube amp. and I'll be the first to admit if I'm wrong, and this time I believe I am. I was going by what I had remembered from about 20 years ago. Carl CEF-357 |
Hotwire
Advanced Member Username: Hotwire
Post Number: 524 Registered: 1-2005
| Posted on Tuesday, August 30, 2005 - 2:43 pm: |
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OK cool, All seems to be workig well. I get good reports. Even talked to Pat00 with it. Thanks guys!! |
Slowhand
Member Username: Slowhand
Post Number: 65 Registered: 7-2005
| Posted on Tuesday, August 30, 2005 - 4:15 pm: |
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Darn, my age is showing! |
Yankee
Advanced Member Username: Yankee
Post Number: 863 Registered: 7-2003
| Posted on Tuesday, August 30, 2005 - 9:37 pm: |
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Look at it from this point of view. Age is only a number that means you can at long last sit back and enjoy your retirement. Although retirement is not all a bed of roses, one has to think of the thorns that come with those pretty roses, known as (health problems and having to learn to live on a fixed income). No worry, you sit there with a smile and visions of January First coming and the yearly raise in your Social Security. Carl CEF-357 |