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#1
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#2
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Steveo wrote:
"Telspam Electronics" wrote: http://cg/spam Things must be slow. didn't he get booted off a provider for spamming? |
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#3
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jim wrote:
Steveo wrote: "Telspam Electronics" wrote: http://cg/spam Things must be slow. didn't he get booted off a provider for spamming? Rumor has it. |
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#4
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"Steveo" wrote in message ... jim wrote: Steveo wrote: "Telspam Electronics" wrote: http://cg/spam Things must be slow. didn't he get booted off a provider for spamming? Rumor has it. Very good layout PC board, that takes allot of work. Hope he sells them all day to CBers, I don't care where they go. Some of the so called BIG amps( Dave Mades, ect ) look crappy inside because the designers are not very bright.Some look like they were built in a cow barn. |
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#6
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JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having no electronic background. I have looked at many of them over the years and have found that they have major flaws such as inadequate cooling, improper tuning, and instabilities/oscillations caused by improper layout and long wires running around all over inside. Because of these issues, their owners must keep a steady stream of expensive output transistors flowing through them... if you know what I mean... LOL www.telstar-electronics.com |
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#7
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On a sunny day (22 May 2006 04:45:06 -0700) it happened "Telstar Electronics"
wrote in .com: JSF... you're right about those "big amps". They are nothing but hay-wired prototypes, mostly designed and constructed by persons having no electronic background. I have looked at many of them over the years and have found that they have major flaws such as inadequate cooling, improper tuning, and instabilities/oscillations caused by improper layout and long wires running around all over inside. Because of these issues, their owners must keep a steady stream of expensive output transistors flowing through them... if you know what I mean... LOL www.telstar-electronics.com Hi, I am reading on your website http://www.telstar-electronics.com/S...Amplifiers.htm about efficiency and conductingangle. My question, has anyone ever attemped a class D (pulse width) modulated amp with MOSFETS for 27Mc? The limit would be the switching time, say if we have 1nS switching FETS, and 37 nS period time, we use a bridge, so per 37 nS we switch 4x = 4nS We dissipate any power (not counting Rds-on losses), could we achieve 80% efficiency? There are also losses from transformer and Pi filter of course. And perhaps you would need a switchmode to get a higher operating voltage, mmm that would bring it down to .8 x .8 = 64 % + filter and other losses.... But it COULD take you into the kW range with cheap FETS? Whatdoyouthink? ;-) |
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#8
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Jan,
Sure you can run class D at 27MHz... the problem is distortion. Class D is very efficient but is really only meant for digital signals. www.telstar-electronics.com Jan Panteltje wrote: On a sunny day (22 May 2006 04:45:06 -0700) it happened "Telstar Electronics" wrote in .com: JSF... you're right about those "big amps". They are nothing but hay-wired prototypes, mostly designed and constructed by persons having no electronic background. I have looked at many of them over the years and have found that they have major flaws such as inadequate cooling, improper tuning, and instabilities/oscillations caused by improper layout and long wires running around all over inside. Because of these issues, their owners must keep a steady stream of expensive output transistors flowing through them... if you know what I mean... LOL www.telstar-electronics.com Hi, I am reading on your website http://www.telstar-electronics.com/S...Amplifiers.htm about efficiency and conductingangle. My question, has anyone ever attemped a class D (pulse width) modulated amp with MOSFETS for 27Mc? The limit would be the switching time, say if we have 1nS switching FETS, and 37 nS period time, we use a bridge, so per 37 nS we switch 4x = 4nS We dissipate any power (not counting Rds-on losses), could we achieve 80% efficiency? There are also losses from transformer and Pi filter of course. And perhaps you would need a switchmode to get a higher operating voltage, mmm that would bring it down to .8 x .8 = 64 % + filter and other losses.... But it COULD take you into the kW range with cheap FETS? Whatdoyouthink? ;-) |
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#9
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Telstar Electronics wrote:
JSF... you're right about those "big amps". They are nothing but hay-wired prototypes, mostly designed and constructed by persons having no electronic background. I have looked at many of them over the years and have found that they have major flaws such as inadequate cooling, improper tuning, and instabilities/oscillations caused by improper layout and long wires running around all over inside. Because of these issues, their owners must keep a steady stream of expensive output transistors flowing through them... if you know what I mean... LOL www.telstar-electronics.com Kind of like building an amp and running it with class C bias? You know what that means? |
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#10
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"Lancer" wrote in message m... Telstar Electronics wrote: JSF... you're right about those "big amps". They are nothing but hay-wired prototypes, mostly designed and constructed by persons having no electronic background. I have looked at many of them over the years and have found that they have major flaws such as inadequate cooling, improper tuning, and instabilities/oscillations caused by improper layout and long wires running around all over inside. Because of these issues, their owners must keep a steady stream of expensive output transistors flowing through them... if you know what I mean... LOL www.telstar-electronics.com Kind of like building an amp and running it with class C bias? You know what that means? I think some of those Amps are getting close to class D now, they drive 250 Watt amps with 5 watts in to a 50 watt driver 10- 13 DB gain then a pair of finals with 10-13 DB of gain, no bias on the base , I can just see the crap the poor transistors go through. Then they mod their radios to give SWING which does nothing but make the wattmeter swing like SSB but their no louder, but I will say it helps keep the poor finals cooler. In the new Commerical Broadcast AM transmitters their Audio is Class D audio amps driving the finals saving allot of AC power. |
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