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Welcome to Decware



Single-Ended Triode Buffer Stage

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The ZBOX has been designed as ultra transparent tube buffer stage.   It can make a massive difference in front of many solid state amplifiers - giving them a more natural sound.   It is also a great tool for people with tube amps who want to improve the sound quality of their source components.


The ZBOX is not just another buffer stage, if it were it would only make things sound marginally better.  It works by creating a starved voltage condition in the filament of the tube that in turn causes an increase in favorable harmonics and a decrease in objectionable distortion.   This makes the ZBOX not "just another magic black box" for which the audio world has seen many, but rather makes it THE magic black box.  Simply guaranteed to improve the sound of solid state source components.

The results are as follows:

  • Restores proper frequency balance though better impedance matching.

  • Improves tone and weight.

  • Relaxes and opens up the music for better detail, imaging.

  • Reduces listener fatigue.

  • Enhances the 3D effect of better recordings.

Yes, you can place a ZBOX between a preamplifier and most power amps.  

Yes, because of its volume control, you can also use a ZBOX as a purist preamp when you only have one source.


The ZBOX features a black powder coated steel chassis with a standard IEC connector and removable power cord.  Available in 120/240 volts for world wide compatibility.

The unit is designed with reduced voltages that only operate the tube at half power so there is no heat, and the tube will last twice as long.  To keep everything at the ideal luke warm operating temperature for best sound, the ZBOX is run 24/7 and has no switch.  It draws less power than a 15 watt light bulb and was specifically designed to stay on continuously.

There are a single pair of inputs and a single pair of outputs.  The input level can be adjusted with the front mounted gain control.  In cases where no preamp is used, this can be used as a volume control.


For audiophiles craving the sound of tubes in their home theater, this can be an excellent way achieve it.  This works well if you have set up your system using separate amplifiers, or if you are running a Bluray or DVD player with discrete outputs for every channel.  In these cases you can run up to three ZBOXes. to cover all 6 channels.  Fronts, Rears, Center and Sub.  This also gives you a physical knob to control volume for each set of speakers. 


The ZBOX uses the popular dual triode 12AU7 of which there are many brands.  This tube sticks out the front so you can easily change it without taking the ZBOX apart.  Typical lifespan in this product is 5,000 to 10,000 hours.  





The following options are available in the shopping cart:

  • Voltage 120VAC or 240VAC

  • Volume Control - Your choice between 20 position stepped attenuator or standard infinitely variable volume control.

  • Anniversary Mod - Film or foil bypass caps added to the power supply pending the type of signal caps you selected.  This increases detail.

  • Anniversary Mod - Tube Regulation is another major power supply enhancement that improves liquidity.



Knob types: Ebony, Gold, Black chicken head, Cream chicken head, Rosewood



Weight - 7 lbs. ea.

Dimensions - 2.5" H x 6" W x 11.0" D

Circuit type - Single ended Class A Triode

Power Supply - Toroidal Linear

Gain - 80% unity

Max Input voltage - 5.7 volts

Max Output voltage - 5 volts

Output Impedance < 1000 ohms

Input Impedance -100,000 ohms

THD - 500mV = 0.5% / 5V = 1.2%

Response - 10 Hz ~ 70 kHz

Feedback - ZERO negative feedback used

Noise - 180Hz = -63dBU 60Hz/120Hz= -73dBU

Signal tube -12AU7 

Biasing - Cathode Bias

Resistors - DALE, VISHAY

Signal Caps - Film or Foil

AC cord - Removable power cord

Consumption - 13.5 watts at full power

Input jacks - RCA type 24K Gold / Teflon

Output jacks - RCA type 24K Gold / Teflon

Warranty - Lifetime to original owner



This product is hand built in the USA by DECWARE / High Fidelity Engineering Co. It comes with a lifetime warranty to the original owner. If you purchase one second hand and ever have questions or technical problems we are happy to check it out for you and service it if needed for a very reasonable rate.

We have never sold this item as kit but that doesn't mean you won't find someone else's work inside if you buy one used.  If this is the case and the work and parts are anything less than what we would do, it will be removed and the ZBOX returned to it's like new condition at the present owner's expense.



Made by hand in the USA and sold wholesale to the public with a 
L i f e t i m e   W a r r a n t y  !

ZBOXES are hand-built to order.  There are presently lots of orders on our real time build sheet.   A 10% deposit secures your place on the list with today's date and time stamp.  Balance is due when it's ready to ship. You will be sent a final invoice with the total price including actual shipping costs by our office during your wait.  NOTE: This item is built on our accelerated build sheet that has shorter wait times.

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