kl203p ssb distortion

[drdr2014]

Need help troubleshooting kl203p issue. Friend of mine just bought this amp. It works great on AM, but is distorted on SSB. Putting about 1/2 W in and getting 75-80 out on AM, audio sounds great.
On SSB, it is distorted no matter what, tried turning down audio and doesn't seem to help. He is running it on a 330 CCA battery with a charger, voltage is staying 13.2-13.8v with amp keyed on AM.
Any suggestions? Thanks.

[MDYoungblood]

What brand of radio are you working with?

3's

Greg

[Crusher]

First thing I would ask, has he tried it without charger. May be getting AC hum.

[MDYoungblood]

Good point but I'm thinking it's not getting enough modulation causing it to sound fuzzy.

3's

Greg

[drdr2014]

Using Uniden Washington. It has plenty of audio on AM and SSB w/o amp. Audio almost sounds overmodulated, but turning it down didn't eliminate the muffled sound. Doesn't sound like an AC hum, but easy enough to check out.

[1206FL]

What is pep wattage being input on SSB? Don't see that posted anywhere? Those amps don't like a lot of drive. So maybe lower power on SSB to stock or even a bit below stock levels of 12w pep on SSB.

[Deleted User 14541]

Using Uniden Washington. It has plenty of audio on AM and SSB w/o amp. Audio almost sounds overmodulated, but turning it down didn't eliminate the muffled sound. Doesn't sound like an AC hum, but easy enough to check out.

If the battery charger isn't causing it try a different radio that hasn't been tinkered with. If it works great on AM there probably isn't an issue with the amp.

Good point but I'm thinking it's not getting enough modulation causing it to sound fuzzy.

3's

Greg

Can you go into more detail about this?

[MDYoungblood]

Good point but I'm thinking it's not getting enough modulation causing it to sound fuzzy.

Can you go into more detail about this?

When he stated driving it with a 1/2w AM, SSB sounds horrible that low but after his next post about overmodulating, I think he answered his own question. What kind of mods have been done to the Washington? Wonder what the stock microphone would sound like?

3's

Greg

[Crusher]

I wonder what mic he is using. Might need a stock mic on SSB. Not a power mic.

[drdr2014]

Quick update. Charger not the isssue, disconnected from battery and no change. Going to try a different radio next. Did hook Washington up to Magnaforce amp and no SSB distortion. Beginning to believe the issue is in the amp.

[MDYoungblood]

It's always the possiblity. I have used a KL203P and an Astron 20amp PS on my Washington driving it with 3 watts DK AM and 12/16 watts SSB, never had a problem.

3's

Greg

[Crusher]

The MagnaForce is a different animal all together. They will take the drive easily. The kl203 is a different animal altogether. That Washington if it's like my old 148, does about 12-15w on SSB. May be too much drive.