Once in a while I get emails with the very same questions:

My power meter shows only 20 W watts in SSB. What’s wrong with my TS-590S?

My amplifier needs 90 W for full output power, but with my TS-590S set to 100 W, I only get 60-70% of the full output. Can you help me?

(Add random question about TS-590S output power)

Here is a short list of things to check, if you think the output power of your TS-590S is weak:

  • Check the power cable and supply voltage. My original power cable, which came with my TS-590S back in 2012, was really a mess. The fuse holders were crappy, the junctions between the twin-leads and the single-leads were crappy and the crimp contacts within the connector were crappy. The result was a voltage drop of 2.4 V on the power cable at 100 W output power and 13.8 V on the power supply. So the supply voltage within the TS-590S was only 11.4 V, which resulted in a massive power drop-off. Since then, I use a self-made power cable with a cross-section of 10 mm² (about 7 AWG), power lugs at the power supply, soldered contacts within the connector and no fuse holders. The voltage drop is now below 200 mV, even at full output power.

    Power Cable
    My TS-590S power cable

  • Check your SSB audio setup. Use this HowTo of G3NRW’s TS-590 Resource Page for proper settings.

  • Don’t think the speech processing can give you 50 W average power in SSB. Please read my notes about the efficiency of the TS-590S speech processor.

  • Make sure, you have a TS-590S with the Kenwood ALC modification.

  • Please be aware of the fact, that the internal power meter of the TS-590S is too slow to show the voice peaks in SSB transmissions. This is a really poor implementation of a power meter, but that’s unfortunately a shortcoming TS-590S(G) users have to deal with. Buy a good peak and average reading power meter to see the peaks and your average output power. I’m using the Telepost Inc. LP-100A.

  • If your TS-590S (not TS-590SG) still has low power issues, let a Kenwood Service Center check the TX section. First models might have a wrong factory alignment with too low bias current for the amplifier FETs. In the first place, a low bias current may cause higher TX IMD products, but if the TX section is misaligned in general, a power drop-off may be possible as well.