Adding SSB to AM amps - how is it done?

[ShakyMcQuiver]

Another project I've had on the back burner for a while: Adding a SSB switch to an AM amplifier.

I have a Texas Star 'Trucker 200', a 'Commander 150A' and other similar 2-pill mobile amps. None of them have an SSB function. I am curious if anyone has a schematic or procedure to PROPERLY add SSB capability to them?

I've seen the YouToob capacitor mod on a Texas Star Modulator (I actually have the V+ model). All that mod does is keep the relay open on TX. It's a cheap down-n-dirty mod that does work, but apparently it's not the best way to go about it from a few posts I could find about it. I have not been able to find detailed information on how a proper SSB mod should be done.

Yes, I know.. just go buy an amp that already has the SSB option. While that's certainly the easiest way to go, I like to tinker with the junk I have laying around and see if it can be re-purposed. All my amps work great. Just like to have that SSB capability if at all possible.

Thanks!

 

[AudioShockwav]

I've seen the YouToob capacitor mod on a Texas Star Modulator (I actually have the V+ model). All that mod does is keep the relay open on TX. It's a cheap down-n-dirty mod that does work,

No, not really.
Sure it keeps the relay closed but it sounds like garbage.
I many years ago tried that with a mod v and everyone knew instantly when I tried to use it in SSB.
Sounds like kornflakes.
Those one transistor class c modulators are just that.
On the two transistor amps you need to isolate the dc ground on the input transformer and apply some bias voltage to get them over the " turn on" threshold.
There is a thread in the amp section about adding a simple bias set-up to a RM amp that would be a good place to start.
And a better thread about bias in general stuck to the top I think.
It covers regulated bias with lots of good info.

73
Jeff

 

[Alabama Buckeye]

Am I muddying the 8 pill FatBoy waters on SSB while driving with it with a driver amp not so enabled?

What is the benefit of having an amp with SSB enabled?

"Sounded Like Kornflakes", what's that soggy flat mush?

 

[AudioShockwav]

First two threads on the top of the Amp Section.

Also good info here.
Read the link below for ssb info.

Transistor PA Bias Circuits

73
Jeff

 

[Captain Kilowatt]

There is a lot more to "adding SSB" to an amp. The switch method most often used simply holds the relay in between voice peaks but most of those amps are class C and sound like crap and spew distortion when run in SSB mode. You need to completely rebias the output transistors so the run at least B and preferably AB.

 

[ShakyMcQuiver]

Thanks for the replies... I figured there was a lot more to making it work than just holding the relay open.

Yea, it works... how well? Apparently not very! Lol.
Good info. though. I'm always trying to learn!

 

[AudioShockwav]

Yea, it works... how well? Apparently not very! Lol.
Good info. though. I'm always trying to learn!

That link about bias above is a very good read, explains why, how, and the best way to build it.

73
Jeff