Treasure KT120-Z CB Cobalt Blue Bottle (GF-Select, Quad)

Please note that the KT120-Z has now adopted a cobalt blue glass enclosure to provide better heat dissipation through the glass enclosure. The new model number is called KT120Z CB – Cobalt Blue bottle. The transparent blue glass allows you to see tube glow but not overly bright to distract listener. See picture below of tubes in action..

Below review is based on the ‘black bottle’ sample tubes provided at the time of review. The glass enclosure change in the tube design will not affect the tube sound in a critical way.

The KT-120s are broken-in now.  The bass is more than there.  Everything sounds excellent.  I have to finish a Synergistic Research review and then I’ll get on this one.  I have no desire to reinstall the Ayon Audio KT-88s if that tells you anything.  It will be a five star review. Thanks, Mike Girardi

Reviewer for stereotimes. Read full review here.


This new addition to the Treasure GF-Select series is to meet the market demand for a warm, lush, and rich sounding KT120 compared to the clinical sounding TungSol KT120.

The KT120-Z CB is of 11cm (4 1/3″) height from bottom of base to top of glass, and diameter of 5cm (2″).


Below pictures are for the KT120-Z  compared to a typical KT88 tube:

Suggested Break-in Time:

Please note: This tube requests extended break-in time to sound to the best. Recommended 150hrs.

Special Note when placing an order: 

As our KT120-Z CB has stronger plate current than some TungSol KT120 tubes, some amps with auto bias circuit plus auto shut-off protection circuit may wrongly take the high plate current as false internal short, so the amp may shut down automatically into protection mode. This doesn’t mean the tubes are defective – strong current is a positive thing in new tubes.

When placing order, please make sure to select the ‘bias mode’ as either ‘Self bias with auto shut-off circuit’ or ‘manual bias’. In general, manual bias amp can accept higher plate current tubes (the higher plate current will also allow tubes to have longer aging time). We will select tubes based on this information provided so that the tubes shipped to you will best suite your amplifier.

All KT120-Z tubes for the time being will be shipped out of Grant Fidelity Canada office, tested on Amplitrex AT1000, and run active on an amplifier for 8 hrs before shipping. Please kindly allow us extra time to selecting and shipping your tubes after the above mentioned process.

Stock Status: 

In stock now for immediate shipping from Canada to worldwide. 

This model comes with additional 90 days warranty on top of our regular tube warranty. Buyers have 180 days from purchase date for warranty against any manufacturer defects. We hope this gives you extra confidence in experimenting the ‘anti-TongSol KT120’ sound 🙂 


Please select:

Price: $495.00

Comments are closed.