new tung sol kt 120

I run Sonic Frontiers SFM-160s, which use four KT-88/6550s per amp to produce 160w. My current situation has Gold Lions in the amps. Great sound.

I exchanged e-mails with Chris Johnson re: the KT-120s. While an increase in power of about 10% is common in SF gear (which of course was not designed to take full advantage of the KT-120s), Chris felt the major benefit in his equipment was the LT reliability. The SFM-160s really push the four KT-88s hard and I do have tubes go a bit more often than I would like. With the KT-120s, the LT reliability issue is much better.

I have not tried this, as I recently re-tubed with matched quads of Gold Lions. Plus, I am very happy with the sound.

wow, i cant believe more people have not tried this tube, I was hoping that there would be more information on it.

From my understanding, the tubes are only recently available on a large scale. Chris J just started to carrying them.

Folks, beware that the KT-120 draws 1.8 Amps heater current per tube, as compared to the KT88 1.6A spec.
A stereo push-pull amp with four KT-120 tubes will draw 800 additional milliamps from the heater winding. The amplifier's power transformer will run hot and possibly fail in the long run.

I think this may be an excellent tube for a new design buit around its strengths.

IMO one can safely try KT-120s only on conservatively designed tube amps with over-specified power transformers that run cool and that use self-bias / cathode bias.

Fixed bias amplifiers need to be modified before one installs KT-120s, so this rules out most USA-made muscle push-pull amps.
I hope this helps.

Casouza,

Help me better understand "self-bias/cathode bias".

My Sonic Frontiers monoblocks use four KT-88s per amp. I have a knob on the amp that allows me to select one of these four tubes. Using a screw driver, I can turn a shaft with a slot in it to adjust the bias using a meter.

Is this a fixed bias amp?

Thank you.