| Author |
Message |
    
Purplehaze
Junior Member
Username: Purplehaze
Post Number: 12
Registered: 4-2004
| | Posted on Monday, May 17, 2004 - 8:07 am: | 
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I bought a maco 750.. well it was keying 300 swinging.. 900... but my tubes have craped out.. i have 9 tubes it has been modififed.. they want 85.00 a tube for 8950's how much trouble would this be to convert to a 6lq6 or something?????? help.. or does anyone know a site that has them cheaper than 85.oo dollars thanks purp |
Sparkomatic
Intermediate Member
Username: Sparkomatic
Post Number: 307
Registered: 10-2002
| | Posted on Monday, May 17, 2004 - 8:43 am: |
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Not trying to be funny or anything but why would you buy an amp with all those expensive glass tubes in it? |
Pig040
Intermediate Member
Username: Pig040
Post Number: 425
Registered: 7-2003
| | Posted on Monday, May 17, 2004 - 9:41 am: |
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Because when they are working they are awesome. It is just bad luck to have the tubes go bad, I have used tube amps for years, and as long as you use the proper tuning procedure, tubes can last for a long long time. Less bleed too! |
Tech833
Moderator
Username: Tech833
Post Number: 698
Registered: 8-2002
| | Posted on Monday, May 17, 2004 - 6:06 pm: |
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It has nothing to do with 'luck'.
It has always puzzled me why many ham and illegal CB amplifiers use so many small tubes instead of 1 or 2 larger tubes. My amateur amp (home brew) uses a pair of 4-400's and will put out well over legal full power of 1.5 KW. The tubes in my amp are probably around 15 or 20 years old and still put out maximum power. They have close to 10,000 hours on them. Tubes in most broadcast transmitters I run last anywhere from a year to 5 years depending on the type and how they are run. That is 24/7! That adds up to around 8,760 hours if I am correct.
A 4-400 is admittedly pricey at nearly $200 new. However, the cost to re-tube Haze's amp is $765 and he was only getting 300 watts carrier. For $400 every 15 years or so, I can get 1,500 watts carrier with no stress at all.
Puzzling... |
Sparkomatic
Intermediate Member
Username: Sparkomatic
Post Number: 308
Registered: 10-2002
| | Posted on Wednesday, May 19, 2004 - 8:05 am: |
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Not to mention trying to find new 6LQ6 tubes plus the Maco 750 constantly had to be retuned....very unstable and annoying. I owned one in 1983.
Instead of investing heavily in an amp like that an Xforce or Davemade base would last forever and out perform the Maco. |
