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Wildrat
Intermediate Member
Username: Wildrat
Post Number: 224
Registered: 12-2003
| | Posted on Friday, November 04, 2005 - 10:25 am: | 
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I know that tubes are alot cleaner than transistors. But I have a couple of questions as usual.
1) If you get a tube amp, how hard are the tubes to find?
2) The tubes cost an arm and a leg as compared to transistors don't they?
3) Is it cheaper to buy a hi-power transistor amp over a tube amp of the same size?
Wildrat
CEF674
P.S. WishI had kept my Golden Eagle tube amp I bought in early 80's rather than sell it when I was short of money. Of course the sale was worth it I got custody of my two boys and was able to give them a more stable upbringing, even if I was single, young, still crazy, and probably needed someone to still raise me. |
Moonraker
Member
Username: Moonraker
Post Number: 53
Registered: 3-2005
| | Posted on Friday, November 04, 2005 - 10:52 pm: |
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I don't know a lot about tube amps, but I know of people around here that can't use the tube type amps they have, they can't afford to buy tubes or just can't find tubes at all. If you find a tube amp you like, do some research to see if you can get replacement tubes for it and if they are in your price range. |
Tech833
Moderator
Username: Tech833
Post Number: 1081
Registered: 8-2002
| | Posted on Sunday, November 06, 2005 - 12:53 pm: |
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Some tubes are more costly than others. Also, some tubes last longer and are more tolerant of mistuning than others.
Depends on the tube type, then we can answer your question.
BTW, it is imerative that you do not push tubes further than they are designed to go (even though it is very easy to do) so that you do not shorten their lifespan. I have tubes in broadcast transmitters that run 24/7/265 for 5 years sometimes. I know one ham with a 4-1000 tube amplifier that has had the same tube in it (still doing 2KW) 15 years later. There is NO reason a set of tubes should not last many, many years of frequent use. it is all up to you.
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Chad
Advanced Member
Username: Chad
Post Number: 553
Registered: 11-2004
| | Posted on Sunday, November 06, 2005 - 8:34 pm: |
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Darn 833, your broadcat year is only 265 daze long? I was working in the wrong part of the country 
As stated earlier, research is key, make sure the tube is still in production, run it wisely and it will do well for you. You do not have to change transistors, you will eventually have to chenge the tubes. It's more expensive and you have to tune it. BUT there's a aura of pride in tube amps be it hi-fi, instrument, or RF. If you are looking for convience then tubes will not be for you. If you have patience and don't mind tuning and maintence then I would go for tubes. I would own a tube amp now but I am saving up for something else... STAY TUNED!
BTW I am listening to a tube Hi-Fi amp right now as I type
Chad |
Tech833
Moderator
Username: Tech833
Post Number: 1083
Registered: 8-2002
| | Posted on Monday, November 07, 2005 - 10:04 am: |
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The main stereo in the 833 living room was made in 1961 and has 21 tubes in it. Oh, and the main radio in my 'shack' was made in 1959 and has 26 tubes in it.
I guess a broadcast year differs fromm the normal year. Ha ha!! Obviously a typo. However, that might explain why commercial breaks seem to take so long....
My advice on tube RF amplifiers is to research the tube (will not give web addy, but you can always search for a tube manual spec sheet online). Look at the mfg.'s plate dessipation value and figure that the RF power from that tube should be about double that number. DO NOT run your amplifier beyond that power level (no matter what the amp maker says it can do) and you will be just fine, your tube(s) will outlast you.
Yes, it is true, an Ameritron 3-500Z amp might be able to do the full legal limit, but that tube is only rated for 1 KW output, tops. Your tube will not last long running it as hard as the amp will go. The reason tubes will run far beyond their capabilities (unlike transistors) is what makes tubes a superior hi-fi means of amplification- Tubes have a LOT of headroom, and a 'soft' clip. Yes, they will go past their rated output, but THAT is when you begin to strip the cathodes and severely shorten their life.
Tuning by the wattmeter is O.K. if you have no other means, but tuning for minimum plate current is always the best way to go. Then, make sure your putput is below the tube's maximum recommended rating and dip the plate again.
Nuff said by me. You guys have the floor now. |
Wildrat
Intermediate Member
Username: Wildrat
Post Number: 232
Registered: 12-2003
| | Posted on Monday, November 07, 2005 - 12:22 pm: |
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Thanks! |
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