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Clean Signals from C Class!!!
- Thread starter 15minigrass
- Start date
Don't know. Not my forte. My suspicions are it's a C class, but I don't know.
Well, here's your answer:
No matter with whom I've spoken over the air, or whether overseas or nearby, I have only been told I have clear clean audio. And the recording seems to say the same. Ironically, only after I revealed this setup have I been told I was crackly. I am only saying that either folks who were supposed to know of these things of which this thread speaks were lying to me, or were too kind to tell me the truth as they heard it, or the ability to discern the difference is not so readily apparent in some cases.
This is not an argument, just a statement relevant to the discussion.
Well, here's your answer:
No matter with whom I've spoken over the air, or whether overseas or nearby, I have only been told I have clear clean audio. And the recording seems to say the same. Ironically, only after I revealed this setup have I been told I was crackly. I am only saying that either folks who were supposed to know of these things of which this thread speaks were lying to me, or were too kind to tell me the truth as they heard it, or the ability to discern the difference is not so readily apparent in some cases.
This is not an argument, just a statement relevant to the discussion.
That's not so ironic. Didn't cbradiomagazine do this test once?
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Yes, but mine wasn't a test. I have used this setup frequently and never said how I generated the wattage and received positive comments, most of them unsolicited.
Don't get me wrong, I prefer good audio to loud audio any day.
The point is, not once previous to my post on this thread when I've used the C class amp in line has anyone ever told me it was less than optimum. I have talked to so many HF rigs I can not keep count, and in every case I was told it sounded very good with clean smooth audio. I did not ask how I sounded, but the reports were volunteered.
I just wanted to see whether the test videos were the standard of audio testing, or whether the standard broke down in some cases. I have been told but once I sound bad, and I trust the person who told me so. No problem there. Take a look at my DX lists for January and February 2012 to see how many times I've been in touch with folks. Fully 90% of those contacts were made with that setup . . .
I am not championing the C class amp. Coincidentally it is what I have.
The irony was not that someone told me it wasn't a good transmission, but that no one seemed to notice until after I posted here.
Don't get me wrong, I prefer good audio to loud audio any day.
The point is, not once previous to my post on this thread when I've used the C class amp in line has anyone ever told me it was less than optimum. I have talked to so many HF rigs I can not keep count, and in every case I was told it sounded very good with clean smooth audio. I did not ask how I sounded, but the reports were volunteered.
I just wanted to see whether the test videos were the standard of audio testing, or whether the standard broke down in some cases. I have been told but once I sound bad, and I trust the person who told me so. No problem there. Take a look at my DX lists for January and February 2012 to see how many times I've been in touch with folks. Fully 90% of those contacts were made with that setup . . .
I am not championing the C class amp. Coincidentally it is what I have.
The irony was not that someone told me it wasn't a good transmission, but that no one seemed to notice until after I posted here.
You sounded really nice on 385 when you were talking skip one day. I couldn't get back to ya due to heavy QRM Homer.
Thnx everyone for the replies, I guess its how you set it up that the signal gets distorted or not. Aloha, James
Thnx everyone for the replies, I guess its how you set it up that the signal gets distorted or not. Aloha, James
Just my observation but It has been my experience that most communicators do not really know what good audio is. Most of them think that if the station is loud and not covered up by QRM then it sounds good. I have heard some truly awful sounding stations on both CB (especially) and on ham as well get told that they are sounding great when in fact distortion or splatter is plainly present. The usual problem with this is that once told they sound great most operators refuse to listen to anything different.
2ct004 (Homer) in qso with 68na555 (Norman)...3GP - YouTube
Certainly should! Clearly shows how a class C amplifier CAN sound better than Mack's rain in spain test even using Bobs AB-1 board.
Now Mack, can you honestly say the video you posted was not skewed in anyway to show bias towards how bad a C class amp could sound? Remember you are not under oath and you do not have to reply, ahhh nevermind we all know the answer.
Hey Homer, I just stumbled across this video, (congrats on the great contact into Belfast!) you were also captured here and I can hear the class C biasing a little in your audio, but the harder class C is driven the harder it is to detect audio distortion so if you have to run a class c amp on SSB, please turn your mic gain up not down. I've even heard guys running a loud fan in the foreground to keep the transistors turned on to help keep the notch distortion almost undetectable.
Also, class C is usually OK sounding on AM if you aren't demanding more than 30% of it's output capability for the carrier.
One thing that's good to do is pick up a good quality heavy-duty manual antenna tuner like a Dentron MT-2000A and put it in line 2nd to last, just before the SWR/watt meter, so when you tune through it you add about 20-30db of harmonic filtering.
MARK 68CT1970 I QSO WITH 2CT004 - YouTube
Also, class C is usually OK sounding on AM if you aren't demanding more than 30% of it's output capability for the carrier.
One thing that's good to do is pick up a good quality heavy-duty manual antenna tuner like a Dentron MT-2000A and put it in line 2nd to last, just before the SWR/watt meter, so when you tune through it you add about 20-30db of harmonic filtering.
MARK 68CT1970 I QSO WITH 2CT004 - YouTube
I don't think that harmonic filtering is gonna help much.
The problem is in the biasing that forces the transistor to overdrive purely for the sake of more watts and a loss of linear amping. Once that is allowed to occur by design, no amount of filtering is going to put 'humpty dumpty' back together again . . . lol . . .
The problem is in the biasing that forces the transistor to overdrive purely for the sake of more watts and a loss of linear amping. Once that is allowed to occur by design, no amount of filtering is going to put 'humpty dumpty' back together again . . . lol . . .
Overdrive?
If you're running, say, 2 2879 transistors good for about 100w pep each, or 200w pep/pair @ 12vdc that would provide 50w carrier and 200w pep AM without ever over driving, however it would be about 55% efficient class AB, 75% class C which runs cooler and requires less current for the same output.
The reason for the class C distortion is the fact the transistors switch off until a small percentage of their power is demanded so they lose that small percentage across the notch between the positive and negative half of the sine wave, causing a gritty sound like the edge of a piece of cardboard dragged across 40 grit sandpaper.
Over driving them only adds to the nasty edgy class C sound on AM if too much carrier is demanded because the transistors are saturating.
The carrier on AM keeps class C sounding clean on AM because it keeps the transistors on so the audio has a clear path to flow instead of like SSB where there is no carrier and the audio does the work of turning on and keeping on the class C transistors, losing some of the clarity across that notch.
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This thread makes me want to buy the P3 panadapter for my K3 so I can post pretty pictures of what various signals look like.
My credit card and wife are all pissed off at you guys now!
if you do buy it, don't forget to post the pics all over the cb section, especially in threads talking about amplifiers ^^ ab v c^^ or tweaking radios ^can not stand it^or even better in the NPC <<More audio>> or whackpack <<More audio>>threads.
although i'm not so sure they would be pretty pictures, come to that i'm not so sure a pan adaptor would have the range to cover the bandwidth of shit eminating from abused cb transceivers.
DXman
Yes, that's 3100 degrees F. Nine yrs of hard work.
Look fellows, I didn't start this thread, and I have no dog in this race. What I did was stick my neck out so there could be more room for discussion. I heard the test and could clearly tell the difference in the audio samples. I offered the recording of my setup over the air for the simple reason that it was quite distinctively different and asked for opinions of what and why.
I am almost exclusively a SSB user, and I have no trouble with the need to run a clean station. However, there must be consistency in the presentation of the debated material in order to have a hope for informing and convincing people like me who believe only what can be substantiated. I appreciate the answers.
I can take the using of my samples: I encourage it. I was only trying to make contacts and someone recorded my QSOs, so there is absolutely no prejudice in the results contained in them which makes them objective materials.
I am almost exclusively a SSB user, and I have no trouble with the need to run a clean station. However, there must be consistency in the presentation of the debated material in order to have a hope for informing and convincing people like me who believe only what can be substantiated. I appreciate the answers.
I can take the using of my samples: I encourage it. I was only trying to make contacts and someone recorded my QSOs, so there is absolutely no prejudice in the results contained in them which makes them objective materials.