| Author |
Message |
    
Jlheart
New member
Username: Jlheart
Post Number: 3
Registered: 4-2010
| | Posted on Thursday, November 11, 2010 - 4:37 pm: | 
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I am driving above amp with about 5 watts in, getting about 90-100 out, and my Pyramid power supply meter says amp is drawing 20 amps. How can this be?
Thanks |
Jlheart
New member
Username: Jlheart
Post Number: 4
Registered: 4-2010
| | Posted on Monday, November 15, 2010 - 2:30 pm: |
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My question is not about the watts I'm getting out (that may be a problem with my Dosey) but how can my Pyramid indicate 20 amp draw with only a 5 watt input to the amp? Oh, and I purchased all of this equip from Copper.
Thanks, Jack |
Sitm
Intermediate Member
Username: Sitm
Post Number: 351
Registered: 1-2004
| | Posted on Tuesday, November 16, 2010 - 10:02 am: |
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The Texas Star 250 uses two 2290 finals. The texas star website rates this amp at 20 watts pep with a 26 amp max draw.
First, is this 5 watts in RMS "dead key", if so you are driving it too hard, use a 2 watt dead key. If your PEP, "swing" is near 20 watts, you will be utilizing more than 20 amps.
Remember, what you dead key isn't what you are driving the amp with, it is your modulation that is pushing the amplifier. |
Jlheart
New member
Username: Jlheart
Post Number: 5
Registered: 4-2010
| | Posted on Tuesday, November 16, 2010 - 4:30 pm: |
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I appreciate your feedback. If by dead key you mean keying the mike with no modulation, that is the way I have been measuring it. I assumed with no modulation that my radio's 5 W out was RMS. Maybe I'm wrong? Thanks. |
Audiophile73
Intermediate Member
Username: Audiophile73
Post Number: 162
Registered: 5-2004
| | Posted on Monday, January 17, 2011 - 12:35 am: |
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Maybe your watt meter is inaccurate. You could be putting way more power into that amp than you think. One option (if you don't have an extra watt meter), plug your radio into you power supply, key the mic. If you radios rf output is 5 watts you should only see a draw of 1/2 an amp or so. I'm curious to hear how you make out. Also, are these test's being done on a dummy load or antenna? |
Jlheart
New member
Username: Jlheart
Post Number: 6
Registered: 4-2010
| | Posted on Thursday, February 24, 2011 - 6:15 pm: |
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Thanks for your feedback Sitm. You got me digging and I figured it all out. First was how to drive the amp. Second was to put my volt-ohm meter on that Pyramid and realize that the voltage was dropping to 7 volts. Have since replaced it with an Astron. All is well. Thanks again. Jack |
Sitm
Intermediate Member
Username: Sitm
Post Number: 393
Registered: 1-2004
| | Posted on Friday, February 25, 2011 - 9:58 am: |
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Voltage drop can cause damage to your amp, be careful and always check your voltage going into your amp, it is as important as checking your swr. |
Jlheart
New member
Username: Jlheart
Post Number: 7
Registered: 4-2010
| | Posted on Sunday, March 06, 2011 - 4:22 pm: |
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For sure it's important Sitm. The voltage regulation on this 20 amp Pyramid was non existent from the day I got it. I hope I just got a bad one and they're not all made that way. Anyway, I'll probably stick to Astrons in the future. Didn't appear to be any damage to the amp. Now I'm on a new discovery mission. Just got an old D&A Maverick 250 tube amp (grey). Best wishes. |
