top of page

Welcome to Decware


Zen Triode Preamplifier

Fully Differential Balanced 


Model ZTPRE v2


Back in the late 1990s Decware's second product was a reference level line stage called the ZTPRE.  The first product was our 2 watt amplifier -- that obviously would have a limited market.  A great tube preamp on the other hand is something that virtually every audiophile can use!  

It looked this this (below) and had a remote power supply.  It was designed for the purist -- free of bells and whistles, just amazingly good sound.


Years later we developed another line stage that featured an on board tube rectified linear power supply.  It was called the CSP and is still made today in its 3rd revision.  A less expensive and tubier sound with similar transparency made it a popular favorite.


Due to its popularity we took the design to a higher level and discontinued the ZTPRE.

Shown left is the current model CSP3 that has become our ultimate line stage for RCA and doubles as a high impedance headphone amplifier.

What we didn't have was a balanced preamp.

Wanting the purist signal path possible we designed a chassis where the entire audio circuit can be point-to-point wired down the center in a width of only 3 inches!

We took a streamlined circuit from our popular CSP3 preamp and doubled it to create a fully differently balanced preamp with a total of 6 tubes.  A linear power supply for the heaters and a linear power supply for the high voltage on each channel makes this dual mono design run cool with tons of headroom.


The entire audio circuit with all 6 tubes is shown above.  Hand-built products like this are rare.  This design has no negative feedback.

The final result is a new dual mono fully balanced Zen Triode Preamp model ZTPRE with dual volume controls.  It features 6 dual triodes (6N1P or 6922), quad linear power supplies and features 1 or 3 inputs with fully adjustable outputs.

This preamp has the transparency of a high dollar passive, but animates the music in a way that passives never will.

It's like a drag car, totally stripped for performance.

For those who want to win the race... or in this case want the best sounding system.



Option 1 - Upgrade from film caps to copper foil caps.

This modification trades musicality and forgiveness for detail and more dynamics.  Which one would be preferable depends on the quality of your source.  Reference level vinyl rigs and DACs usually benefit from this upgrade, while mid-fi sources often sound better without this upgrade.


Option 2 - Stepped Attenuators

This modification features dual 48 position stepped attenuators in place of the regular volume controls.


Option 3  Faceplate / Knob colors


Choose between Red or Black faceplate with Black or Silver knobs.

DSC_0087 2.JPG

Option  4 - RCA input

You can configure one of the inputs as an RCA input vs. XLR input.  This is done by installing a transformer to create a balanced signal from an RCA jack.   This means you would have one RCA input and two XLR input on each channel.


Option  5 - Inputs

Default is one pair of inputs.  You can also have it built with three pair of inputs.

These options can be selected  and priced out in the shopping cart



Each ZTPRE ships with premium hand selected tubes that have been tested and matched in your actual preamp.  After testing they are red-tipped to show they are a reference set.


Weight 18 lbs. ea.

Dimensions 3.5" H x 17.00" W x 10.75" D

Circuit type  Single ended Class A Triode SRPP

Output Adjustable 0 ~ 25 volts into 100kOhms

Max input voltage  10.5 volts RMS 

Noise / Hum - 58 dB

Input Impedance  
100 k Ohms

Output Impedance  
600 Ohms

Response 5 Hz ~ 100 kHz +/- 4dB   20 Hz  ~ 20 kHz +/- 0.7dB

Distortion at 10.83 VRMS output into 100K is 0.4% THD

Feedback ZERO negative feedback used

Rectification Ultra Fast Recovery Bridge

Signal tubes  6N1P-EB

Biasing Self-Biasing circuit - never needs adjustment

Resistors All resistors are audiophile grade

Signal Caps  Cryo treated Copper Foil Beeswax

Filter Caps  All filter caps are premium quality 

AC cord  IEC connector provided with removable power cord

Fuse - Dual Fuse holders / one per channel / external

Consumption 109 watts at full power 

Input jacks  High Quality XLR 

Output jacks High Quality XLR 

Warranty Lifetime to original owner / 90 days on tubes


Since we don't have dealer's and we sell our amplifiers directly to the customer, our customers have a direct line to us.  As a result, Decware support is legendary for over 25 years.

Support is not only a phone call or email away at any time, but when you purchase this amplifier you join a huge family of customers who also own one and enjoy supporting each other on the:



Screen Shot 2023-11-05 at 6.37.38 PM.png

Manual is in a .pdf format



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  !

Screen Shot 2022-02-12 at 8.15.16 PM.png
Screen Shot 2022-02-12 at 8.15.16 PM.png
Screen Shot 2022-02-12 at 8.19.17 PM.png

These 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.   



bottom of page