top of page

Welcome to Decware



2.3 WATTS x 2  or  6 WATTS x 1


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

The Zen Triode Amplifier


Video Review of the Amp


This is the amplifier design that I started DECWARE with in 1993. It's been over 25 years since that first amp and now there are many thousands in service around the world -- each one has been hand built here at our shop.  The SE84UFO25 is everything we've learned in that 25 year period applied to this ageless design with simply stunning results.  This amplifier is one of my favorite children.  A child that teaches the father.


Steve Deckert - DECWARE / High Fidelity Engineering


25th Anniversary Zen Triode Amplifier


  • 6P15P-EV output tubes driven by a 7DJ8 or 6N5P dual-triode.

  • 2.3 watts RMS per channel or 6 watts in mono into the most difficult loads.

  • 3 independent tube-regulated power supplies - one for each audio tube.

  • Vacuum-tube rectification - brute force power supply that is oversized by 261%.

  • Pure Class-A single-ended triode operation for absolute perfection in linearity.

  • Zero negative feedback for absolute perfection in timing and sound-stage depth.

  • Decware Ultra Fidelity Output (UFO) ultra wide bandwidth output transformers.

  • Runs speakers between 2 ~ 16 ohms with Hi /Lo impedance switch for each channel.

  • 24K Gold-plated components with black oxide hardware and your choice of knobs.

  • No circuit boards so magnetic fields are in 3D space where we can control them.

  • Analogue bias meters, one for each output tube to show you real-time current draw.

  • High-mass .125 steel powder-coated and baked chassis for low microphonics.

  • African Padauk hardwood with Janka hardness of 1,970 lb is standard for this amplifier. 

  • Lifetime warranty to the original owner on parts and labor. 


The SE84UFO25 uses individual voltage-regulation tubes for both the input stage and each tube in the output stage.

This approach cleans the high voltage power beyond what is possible with external power re-generators. In fact it's like listening to batteries with bottomless current. 

This approach is not possible in other amplifiers because VR tubes are rated at around 30mA and most output tubes draw well over that! Luckily the Zen Triode amplifier uses an output tube that draws only 25mA making this unique opportunity possible.

All of this makes the power supply a little more complicated than our other models... In fact there are only 2 resistors and 1 capacitor in the entire signal path of this amplifier. Everything else you see (pictured right) is the power supply.


There are additional benefits as well. The are three types of voltage-regulator tubes that can be used. Each one has its own voltage drop and corresponding number. So by changing the voltage regulator tube you change the voltage feeding the input tube which changes how it sounds. 


What this means is that if you buy an expensive input tube you will now be able to hear it with three different plate voltages instead of one. The sound goes from dreamy and euphoric to tightly focused and highly accurate. This ability to hear three different sounds from the same input tube when combined with use of the input-tube's bias switch doubles it to six different sounds.


This unique voicing tool has proven legendary over 25 years with only two sounds and now there are six. Since dream tubes sound like heaven in some gear and like crap in other gear it is logical to assume it's the operating points that determine the sound. The reason for this is the differences in voltage and current from one piece of equipment to the next relative to what the particular tube prefers best. The Anniversary Zen Triode lets you find that magic operating point for any input tube by ear with these 6 operating points so you know when it's perfect.

What sets this amplifier apart?

It pushes the sonic envelope farther than anything else we've made.  It is the result of taking the original amplifier design that started Decware over 25 years ago and applying everything we've learned in 25 years to create an Anniversary Edition just to see how good can this design can actually sound when you no longer worry about the point of diminishing returns and just go for it. 


There is an entire design log in our forums, a diary of sorts, that shows what happened during listening trials... and what I experienced during the 6 months before it's release...

One of the takeaways is imaging and resolution that will actually melt your face off in a real listening room. So if you are one of those audiophiles who is lucky enough to create a serious dedicated listening space with engineered treatments the differences between this amp and other reference gear becomes impossible to ignore and extremely difficult to beat.


The design maintains a purist and minimalist approach which is why it only has one pair of input jacks and why those jacks are located less than one inch away from the input tube.  

If you plan to run the amp without a preamp and need more sources we have a silver-contact switch box available. Also if you plan to run balanced signals to the amplifier we have a balanced input transformer. These two compatible items are our models ZSB and ZBIT, both available on this site.

Designed with a fully-floating output stage the amplifier can be run in mono by series connecting the output jacks.  This approach avoids the dreaded parallel bridging smear common with most stereo amps when strapped into mono.  Transparency is protected with no audible trade-offs and 3 times the power. So if you get one of these amplifiers, fall in love with it but wish it had more power, get a second one.

As a bonus, this design when bridged into mono with nothing more than a custom cable set can be run as fully differential balanced amplifiers which often takes things up another notch!


25th Anniversary Zen Triode Amplifier


You may choose from several kinds of wood base for your amplifier.


The standard finish is African Paduke.  You may also order Cherry, Maple, Oak, Walnut or custom woods for an additional charge.  Custom finishes or exotic woods make the purchase non-refundable and will be quoted upon request.



Knob types: ebony, gold, black chicken head, cream chicken head, walnut



This amplifier comes with a hand-selected tube compliment.  The large tube in the middle is the 5U4 rectifier.  The small signal tubes to the left and right of it are a 7DJ8 and a 6N5P.  Only one is used in the amplifier at a time, but they both sound different.

Directly to the left and right of the signal tubes are a pair of the 6P15P-EV output tubes.  Both are rated at 10,000 hours and have gold grids and thicker glass.  The amplifier can only use one pair at a time.  The other pair is a spare set.

In the top left are a pair of OA3 voltage regulator tubes that plug into the rear of the amplifier.  These regulate the voltage for the output tubes.

In the top right are a set of 3 voltage regulator tubes.  One is an OA3, one is an OC3 and short one is an OD3.  These set/regulate the high voltage for the input tube.  Each one creates a different sound from the input tube.  Between these three regulators and the two input tubes you have 6 possible sounds.  For example, the OA3 has the strongest and tightest presentation with either input tube while the OD3 has a seductive dreamier effect on the input tubes.  The OC3 is right in the middle.

The 6 possible sounds from the input stage is doubled by the input tube bias switch.  The switch adds gain and punch in one position and a more balanced laid back presentation in the other.

The little thing in the center at the top is an input tube pin straightener.  No self-respecting tube audiophile should be without one.

In the center of the bottom between the dragons is an 8 pin socket saver for the rectifier tube.  If you're exploring the world of rectifiers you will be stunned how much they effect the sound of the amplifier and therefor may want to try several.  The socket saver keeps the amplifier socket from wearing out during your tube rolling adventures.


The 6 empty holes at the bottom are for your personal selection of input tubes in case the two we supplied are not enough ; )


Weight 17 lbs. ea.

Dimensions 8.0" H x 8" W x 16.0" D

Circuit type Single-ended Class A Triode

Power output 2.3 watts  RMS x 2 or 6 watts RMS x 1

Input voltage 1.5 volts for full output

Noise / Hum -79 dBU / -58 dBU@120HZ

Flat Response 10 Hz ~ 80 kHz

Feedback ZERO 

Rectification 5U4G / tube rectification - or 47uf compatible substitues.

Output tubes SV83/6P15P-EV or EL84/6BQ5

Signal tube 6N5P or 7DJ8 and compatible with 6N1P or 6922 or 6Dj8 

Voltage regulation tubes: OA3, OC3, OD3

Transformers Decware UFO wide bandwidth 

Biasing Self-Biasing / Cathode Biased

Resistors precision WW/MF by DALE, VISHAY

Signal Cap MIFLEX or VCAP copper foil

AC cord Removable power cord

Consumption 65 watts 

Input jacks RCA type Gold / Teflon

Output jacks 5-way binding posts accept 12 gauge

Speaker dB/1w 89 dB minimum / 94 dB or higher is ideal

Warranty Lifetime to original owner


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 20 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 our support forums.




Manual is in a .pdf format

If you want to know everything there is to know about this Anniversary amplifier, you can read the whole storey in the design log which can be found in our support forum.  It takes you through the design of the first prototype and the subsequent listening tests as they happened over several months.



Return IT if not satisfied FOR A 10% RESTOCK FEE !


2.3 WATTS x 2  or  6 WATTS x 1


Made by hand in the USA and sold wholesale to the public with a l
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

Amps 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.   


Listen to one and find out what our very best sounds like!

bottom of page