New: KT-170

[steve]

This is the first I have heard of this tube number by Tung Sol. Claiming plate dissipation of 85 watts and
screen grid rating of 11 watts. Tube is 6" tall. Here is a link to data.

https://vacuumtubevalues.com/wp-content/uploads/2021/04/KT170-datasheet.pdf

cheers

steve

[Nick B]

Steve,

How would these values compare to something like a KT 88? Any idea if the build of this tube is likely a result of a special order by an equipment manufacturer or if TungSol built it with the assumption that equipment manufacturers will start utilizing it in their designs?

Nick

[tmazz]

Although the tubes in the KT series are plug in compatible with each other not all amps can use the higher tubes. In addition to the fact they many amps originally designed got KT 88s have output transformers that cannot handle the higher wattages put out by the KT 120s and 150s, the 120s and 150s pull 25% more heater current and many amps designed around KT 88s do not have power supplies with the capacity to provide that much heater current.

While all of the data sheets that I can find for the new KT 170s havre the heater specs redacted I would assume that would pull at least as much current as the 120s and 150s.

If you have an amp designed around 120s or 150s you might get away with rolling in 170, but I would think it is doubtful that you would get away with in on a KT 88 amp, as the 170 has more that twice the plate dissipation of an 88.

But in any case I would check with the amp's original manufacturer for guidance.

[tmazz]

I found an unredacted Data sheet for the KT-170s and the do pull the same heater current as the 120s and 150s.

https://vacuumtubevalues.com/wp-content/uploads/2021/04/KT170-datasheet.pdf

[Nick B]

Although the tubes in the KT series are plug in compatible with each other not all amps can use the higher tubes. In addition to the fact they many amps originally designed got KT 88s have output transformers that cannot handle the higher wattages put out by the KT 120s and 150s, the 120s and 150s pull 25% more heater current and many amps designed around KT 88s do not have power supplies with the capacity to provide that much heater current.

While all of the data sheets that I can find for the new KT 170s havre the heater specs redacted I would assume that would pull at least as much current as the 120s and 150s.

If you have an amp designed around 120s or 150s you might get away with rolling in 170, but I would think it is doubtful that you would get away with in on a KT 88 amp, as the 170 has more that twice the plate dissipation of an 88.

But in any case I would check with the amp's original manufacturer for guidance.

Thanks, Tom. Very interesting. Any idea if a patent would apply to the 170?

[rollo]

  Are these tubes made in China ?

charles

[tmazz]

Although the tubes in the KT series are plug in compatible with each other not all amps can use the higher tubes. In addition to the fact they many amps originally designed got KT 88s have output transformers that cannot handle the higher wattages put out by the KT 120s and 150s, the 120s and 150s pull 25% more heater current and many amps designed around KT 88s do not have power supplies with the capacity to provide that much heater current.

While all of the data sheets that I can find for the new KT 170s havre the heater specs redacted I would assume that would pull at least as much current as the 120s and 150s.

If you have an amp designed around 120s or 150s you might get away with rolling in 170, but I would think it is doubtful that you would get away with in on a KT 88 amp, as the 170 has more that twice the plate dissipation of an 88.

But in any case I would check with the amp's original manufacturer for guidance.

Thanks, Tom. Very interesting. Any idea if a patent would apply to the 170?

I cant imagine they would release a new tube to the market without some kind of patent protection. Too much R&D expense in developing one to let anyone copy it.

[tmazz]

  Are these tubes made in China ?

charles

Tung Sol is now a division of New Sensor, the same Russian company that makes Sovetk and Electro-Harmonix tubes. The are made in the Reflektor plant in Saratov, Russia

[P.I.]

  Are these tubes made in China ?

charles

Tung Sol is now a division of New Sensor, the same Russian company that makes Sovetk and Electro-Harmonix tubes. The are made in the Reflektor plant in Saratov, Russia

They also now make the Svetlana line.

Years ago I sold my beloved Cary 572SE MkII mono blocks due to the tube shortage.  If I had known that New Sensor would be producing that tube I would still have them as my main squeeze. 20 of the biggest watts on earth!

I'm looking for a pristine pair now.

[steve]

Steve,

How would these values compare to something like a KT 88? Any idea if the build of this tube is likely a result of a special order by an equipment manufacturer or if TungSol built it with the assumption that equipment manufacturers will start utilizing it in their designs?

Nick

Sorry I am late responding Nick.

Tube shape is different than 150, may or may not mean anything. Like the 150 and 120, the high plate voltage can be a cause for concern in beam/pentode mode as voltage spikes could be high enough for arcing between pins 3/plate and 2/filament. In UL or triode mode, 600 volts, I would not be too concerned.

The Chinese tried manufacturing the EL-156, but evidently a bust as I don't see it sold in the USA anymore. It also had a high voltage rating but the screen was designed for a lower voltage, so triode/UL operation was limited to a lower screen voltage, dissipation, thus efficiency.

The KT-88/120/150 has a higher screen voltage rating for more efficient use in UL/triode mode. In beam/pentode mode the high screen voltage makes the tube less efficient.

The 170 has a great cathode emission rating of 300ma, the 120 is 250ma and I believe the 88 is around 230ma.

I don't know concerning your last question of manufacturers. Years ago I tested the new tung sol
6550 and was not impressed sonically. Maybe the 120/150/170s are different though.

cheers

steve

[Nick B]

Steve,

How would these values compare to something like a KT 88? Any idea if the build of this tube is likely a result of a special order by an equipment manufacturer or if TungSol built it with the assumption that equipment manufacturers will start utilizing it in their designs?

Nick

Sorry I am late responding Nick.

Tube shape is different than 150, may or may not mean anything. Like the 150 and 120, the high plate voltage can be a cause for concern in beam/pentode mode as voltage spikes could be high enough for arcing between pins 3/plate and 2/filament. In UL or triode mode, 600 volts, I would not be too concerned.

The Chinese tried manufacturing the EL-156, but evidently a bust as I don't see it sold in the USA anymore. It also had a high voltage rating but the screen was designed for a lower voltage, so triode/UL operation was limited to a lower screen voltage, dissipation, thus efficiency.

The KT-88/120/150 has a higher screen voltage rating for more efficient use in UL/triode mode. In beam/pentode mode the high screen voltage makes the tube less efficient.

The 170 has a great cathode emission rating of 300ma, the 120 is 250ma and I believe the 88 is around 230ma.

I don't know concerning your last question of manufacturers. Years ago I tested the new tung sol
6550 and was not impressed sonically. Maybe the 120/150/170s are different though.

cheers

steve

Thanks, Steve. I appreciate your thoughts