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Adding SSB Delay into an amp
- Thread starter iceman78
- Start date
it wouldn't be complacated , but that's a class c amp to begin with. They usually don't sound very good where SSB is concerned. But what the hey ! they been doing it for decades on the class c units. Go figure ? must be a selling point thing ?
I suppose it has become a quality thing for me over the years. To many times over the years I've heard the differents between class c and ab where SSB is concerned and it tends to be like night and day as far as quality sounding is concerned. (and cleanliness of operations) Quality is one thing , sounding any way you want is another. Class c will work on SSB all the same.
I suppose it has become a quality thing for me over the years. To many times over the years I've heard the differents between class c and ab where SSB is concerned and it tends to be like night and day as far as quality sounding is concerned. (and cleanliness of operations) Quality is one thing , sounding any way you want is another. Class c will work on SSB all the same.
I can't answer the question posed either. But I know that 'Fatboy' will mod their amps for SSB before you buy them - for an extra $50.
Maybe you could email them and ask them - I'm sure they could give you that info. You already own one of their amps - right?
You can't expect it perform the same way on AM once it has modded. Class C biasing of the pills isn't the same as the bias used for SSB. A little like buying a Ford and trying to turn it into a Chevy. If you want a Chevy; buy one...
Maybe you could email them and ask them - I'm sure they could give you that info. You already own one of their amps - right?
You can't expect it perform the same way on AM once it has modded. Class C biasing of the pills isn't the same as the bias used for SSB. A little like buying a Ford and trying to turn it into a Chevy. If you want a Chevy; buy one...
You might try putting an electrolytic capacitor across the relay coil. Watch the polarity.
You'll have to experiment with values.
You'll have to experiment with values.
Yeah the most common value is the 1000 uf, I installed a variable delay on one of my experimentals which works well but I would have to open it up to be sure of any values.
Not to be critical, but actually while this will work, it is *NOT* the best way.
Here's why: The keying transistor already has to engergize the relay coil. Hard work. But having to charge up a 1000uf capacitor is also hard work. If you really want to get technical you could check out the time constant of the circuit, but really, this is a band aid approach.
Now, let's also hope that whoever built the amplifier put a doide across the relay contacts to prevent a spike as the amplifier is unkeyed. The effect of the magnet coming back at the coil can cause a pulse that can also take out the keying transistor.
If you really want to do this correctly, you should add the delay to the base of the keying transistor. You will need a small value electrolytic. Polarity is dependant upon what transistor is used. (PNP or NPN)
Usually about 22mf, but in reality it all depends upon the keying transistor used. This causes the keying transistor to remain in an "ON" state after the current has gone away from the rectifiers / diodes that are sampling the RF. It can also help prolong the life of the keying circuit as well, as some are designed poorly, and the keying transistor is actling like a switch, turning on and off quicker then the eye can blink, but obviously too fast for it to affect the relay.
Here's why: The keying transistor already has to engergize the relay coil. Hard work. But having to charge up a 1000uf capacitor is also hard work. If you really want to get technical you could check out the time constant of the circuit, but really, this is a band aid approach.
Now, let's also hope that whoever built the amplifier put a doide across the relay contacts to prevent a spike as the amplifier is unkeyed. The effect of the magnet coming back at the coil can cause a pulse that can also take out the keying transistor.
If you really want to do this correctly, you should add the delay to the base of the keying transistor. You will need a small value electrolytic. Polarity is dependant upon what transistor is used. (PNP or NPN)
Usually about 22mf, but in reality it all depends upon the keying transistor used. This causes the keying transistor to remain in an "ON" state after the current has gone away from the rectifiers / diodes that are sampling the RF. It can also help prolong the life of the keying circuit as well, as some are designed poorly, and the keying transistor is actling like a switch, turning on and off quicker then the eye can blink, but obviously too fast for it to affect the relay.
Although the delay is an important part, more importantly, your power transistors need to be slightly biased to work properly on SSB. This usually involves adding a power resistor and a diode to the circut. Google for the schematic of any amp that has SSB capabilities and you'll see how it's done. If your not electronics savy, it can be a challenge. Just adding a delay alone will not work.
Did you ever get the 1x4 set up for side band, and if so what did you do to the amplifier? Just wandering what the outcome was.
Ice has not logged in in over 5 years.
As has been said already, you can add a delay to the relay but this will not address the lack of bias.
If it is a comp style class c amp it's going to sound crunchy on SSB.
73
Jeff
As has been said already, you can add a delay to the relay but this will not address the lack of bias.
If it is a comp style class c amp it's going to sound crunchy on SSB.
73
Jeff
Hey Longrider, a Fatboy, Davemade and most other linears meant for max AM wattage are not suitable for sideband. The circuits are optimized for max AM wattage, but the distortion this causes on sideband will make you sound terrible.
Over the years, a lot of linears have been sold with a switch marked "SSB", connected to a delay capacitor. It holds the relay closed between syllables and prevents it from chattering on SSB. The real issue is the rest of the amplifier's design. Costs more to make it sound clear on sideband, and there's a double whammy. Making it sound clear reduces efficiency. This in turn reduces the max power you'll obtain. Amp builders have every incentive to push their designs to the last possible Watt. Making them sound good on sideband will work against that result. The guy who shows the most Watts gets the sale. Not the guy whose amp design sounds best.
That "SSB" switch on a great many amplifiers is a pure fraud.
73
Over the years, a lot of linears have been sold with a switch marked "SSB", connected to a delay capacitor. It holds the relay closed between syllables and prevents it from chattering on SSB. The real issue is the rest of the amplifier's design. Costs more to make it sound clear on sideband, and there's a double whammy. Making it sound clear reduces efficiency. This in turn reduces the max power you'll obtain. Amp builders have every incentive to push their designs to the last possible Watt. Making them sound good on sideband will work against that result. The guy who shows the most Watts gets the sale. Not the guy whose amp design sounds best.
That "SSB" switch on a great many amplifiers is a pure fraud.
73
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