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Author Topic: Linear, Solid State vs. Tube?  (Read 47339 times)
KX2T
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Posts: 1101




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« Reply #90 on: January 07, 2015, 05:42:17 PM »

As far as IMD when you look at how many hams want that HiFi audio running 3-4Khz wide just so they can use a little more bandwidth is something I just don't get, SSB is not HiFi orientated but AM is so that one cause of IMD, another cause is overdriving a SS radio's alc were if you just add a small bit of processing and then lower the alc down below the red lines on most of the rigs out there you will still have the so called punch you want without getting the exciter dirty going into your amp. Then the fact that if you do not have to drive the exciter at the full 100W to drive the amp you will in most cases wind up with a cleaner signal. Having good audio is one thing but taking up more space then you need on the dial for that HiFi audio seems IMO a waste of time and space. There are many on these forums who black ball 12V finals in SS rigs that don't seem to realize if drive at lower power levels they are much cleaner as far as there IMD spec.
BTW Dan nice install on your verticals and I bet you buried a bunch of radial under them as well Wink.
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K6AER
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Posts: 5743




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« Reply #91 on: January 07, 2015, 09:41:49 PM »

An Amplifier, no matter how linear, will not clean up poor IMD presented at the input. This is right up there with negative loss coax.
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W9FIB
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« Reply #92 on: January 08, 2015, 03:11:02 AM »

An Amplifier, no matter how linear, will not clean up poor IMD presented at the input. This is right up there with negative loss coax.

In my simplified understanding, if the radio itself puts out garbage, the amplifier will just make it bigger.
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73, Stan
Wisdom is knowledge you gain after you know it all.
KX2T
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Posts: 1101




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« Reply #93 on: January 08, 2015, 06:36:18 AM »

I Have seen tests on rigs at 100W that are not the best and lowering that radio to lets say 50-60W will improve IMD performance. Then if many of these amps don't need 100W for full power you will be fine, most SS or ceramic tube amps can easily be driven with between 40-60W to obtain its full power out. So the point being if you clean up the garbage going in there is no issue's. You guys seem to hump a dead horse about IMD way to much on these forums.
Now if an amp needs the full 100W and the exciter is dirty at the 100W level like driving a pair of 3-500's, you will end up with IMD issues
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