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An article that explains where we're coming from.


of these

2 watts do anything?

Survives a Train Wreck!



  M O D E L   S E 8 4 U F O

  2 watts per channel stereo or 6 watts mono

Hand Crafted in the USA and sold Factory Direct with a
L i f e t i m e   W a r r a n t y  !

Read the full review in this issue of Tone Audio, just click here. "For those who adhere to the 'first-watt' theory of HiFi, here’s a bonus: the Decware Zen amplifier gives you two. Yep, two watts per channel single-ended triode. I must admit they are pretty big watts, as I had no problem driving my reference GamuT S-7’s to a more than reasonable level. (The S-7’s have a rated sensitivity of 89db at 1 watt and a retail price of $42k per pair.)"

"What really sets the Zen apart from all the moderately priced tube amplification I've heard is its incredibly lifelike tonality and bass control."

-Jeff Dorgay, Tone Audio Magazine

  • It's Hand Crafted directly by Decware - A notch above mass-produced retail.
  • A signal path featuring a mere 2 resistors and 1 capacitor.
  • Decware's highly interleaved UFO output transformers made in the USA.
  • It's a class A SET amplifier that can handle dips down to 1 ohm.
  • 7 revisions spanning 16 years.
  • Direct feedback from 6200 customers creates a highly evolved product.
  • Cryo-treated film and foil beeswax capacitors 15 years in the making.
  • Point-to-point wired with no circuit boards in our Zen Dream Shop.
  • Designed by audio guru Steve Deckert

Built in USA with USA parts and labor...  Not mass produced but rather lovingly crafted by some of the worlds best.

If the amplifier were offered in the retail market, which it's not, the retail price would be $2500.00

If you're new to Decware or don't know owner/designer Steve Deckert, or how he started Decware in 1996 with this very amplifier, then when you do, you'll quickly understand why the sound quality of this amplifier is simply untouchable for what it is.

Well OK, you can touch it...

The Zen Triode Amplifier (SE84UFO) is an SET which means Single Ended Triode. It uses a single EL84/6P15P output tube per channel driven by a 6922/6N1P dual triode. The two stages are connected by one capacitor giving the entire signal path a parts count of only 4 components; A capacitor, a transformer and 2 resistors. The amp is built point to point with only 11 solder nodes between your source and your speakers. In addition to this extreme simplicity, there is also no negative feedback. The resulting transparency would be impossible from any solid state design and even most tube designs.

This circuit features a floating output stage that can be series or parallel strapped into mono making it easy to have more power by simply adding a second amp.

The amp features a pair of inputs that are selected via a silver contact toggle switch located at the front.  There is also a volume control on the front that can be used for volume when running direct with no preamp, or can be used as a gain control when being run with a preamp.

The amp also features a self biased output stage which is 100% stable making bias runaway and premature tube failure obsolete.  It eliminates tedious adjustments making the amplifier virtually maintenance free. 

UFO stands for Ultra Fidelity Output transformers. These proprietary Decware transformers push what's possible in a boutique output transformer design with a high degree of precision and the very best steel yielding a bandwidth 5 times wider than human hearing so that the response in the audio band becomes ruler flat.

Worried about 2 huger than life SET watts not being enough power?

The SE84UFO employs a unique floating output transformer scheme where the negative speaker wire is not tied to chassis ground. That means when the amp is bridged, both channels may either be series or parallel wired. In series, both channels work as one and transparency is preserved.

So with no sonic drawbacks to running the amps in mono, you can expect 6 dB of additional power rather then the expected 3dB. This is thanks to the power increase the amp has when it sees half the speaker load from being series bridged.

We have successfully driven hundreds of different loudspeakers ranging in efficiency from 90 to 100dB 1w/1m. On 90dB speakers it works nicely in smaller rooms or for late night out of body experiences.

96 dB speakers will for example make your Zen Triode amplifier sound as loud as a 70 watt amplifier running 84 dB speakers.

When these amplifiers were first released in 1998 there were a minimal number of present day "high efficiency" speakers to choose from that didn't break the bank... Fostex, Lowther, Klipsch and a few others.  Today companies like Decware, Omega, Zu and dozen of others all make speakers that are around 94dB or higher and that's all you need to rock out with a Zen Triode Amp. 

If you own regular hi-fi speakers that you've always loved and are afraid this may not drive them - understand two things: A) It will drive them louder than you're expecting and B) you can bridge these amps into mono for up to three times the power.

JUNE / 2015

The SE84UFO features a switch to go between 4 and 8 ohm speakers as a result of the UFO high bandwidth output transformers that now come standard inside every Zen Triode Amplifier.  This switch can be operated while listening to music and it is recommended to do so as both settings will work on almost every speaker.  The correct setting is the one that sounds the best to you.

Your amp is shipped with hand selected premium quality N.O.S. 6P15P-EV output tubes rated at 5000 hours. These Russian military spec tubes are the top grade of what we came to know in this country as the SV83.

NOTE: You can also use EL84's in this amplifier without adjustments of any kind however you'll find the 6P15P-EV's to be unparalleled in speed and detail. The reason for this is because the 6P15P-EV is actually a video tube as opposed to an audio tube. This gives it much wider bandwidth than a normal audio tube and that results in great SPEED.

We think these small bottle tubes are some of the best sounding and best quality available today. Of course, with the nearly as good sounding EL84 options out there, you can have a different sounding amp just by changing output tubes.

The input tube is a single 6N1P, 6922 or 6DJ8/7DJ8 - your choice. 6N1P's have the warmest tone, 6922's have the best dynamics, 6DJ8's have the most air and micro-detail with a touch less bass. Again, a powerful tool for voicing your amplifier to your particular tastes.

The rectifier is  5U4G,  also
compatible with 5AR4, 5Y3GT, and some 274B. Many owners of this amp like using the 274B however not all 274B tubes are completely compatible, so we ship the amp with one that we know IS. Each rectifier change will also make audible differences in the sound and performance of the amplifier.

This amplifier 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 WILL be happy to check it out for you and service it if needed for a very reasonable rate.

We also have a support forum with many people who own this amplifier who's experiences you may benefit from.

Tone Audio Magazine called it the Best Watts You'll Ever Buy ...  and CNET's Steve Guttenberg says:

"Trust me on this; you'd be amazed how good a few watts can sound, and when they're matched with the right speakers, micro power amps can definitely play loud enough to annoy your neighbors. You're skeptical? I don't blame you, but Decware amps are sold with a 30-day money-back guarantee, and the company wouldn't have lasted 15 years if it didn't have lots of satisfied customers. Business is so brisk there's usually a 30-day waiting list for new customers."

You may read all of the Zen Triode reviews here - going back over 15 years and customer comments like this:

"Hi Steve,

Hope all is well with you and your family?
I have been very fortunate to have picked up an Se84CKC amp over here in the UK.

Wow......I can't believe how great it all sounds.
I have owned all sorts of power amps in the past, 300b, 45,EL34 but your amp surpasses them all. I quite liked the 45 monos but they never went loud enough even though I have Khorns. No such problem with your amp however and as you quite rightly say the speed and attack is amazing out of a mere 2 watts! I agree with your opinion of the output valves, I always enjoyed the El 84's as being a very sweet sounding valve in the days when I had a Leak stereo 20 and these Russian valves are a step up......really remarkable.

I am so glad I took the chance on your products and now have a complete set and am very happy. Vinyl is my preferred medium and I am really enjoying revisiting my favourite albums. It's incredible what is stored in those grooves.

Anyway,I really appreciate Decware's philosophy and continuing efforts to provide guys like me with the chance to own top notch sound at very reasonable prices....long may it continue!
Kindest regards"


Model SE84C

C / Manufactured from 1998 to 2008 and was retired at serial number 1000.

This unassuming little gray box (about the size of a toaster) set the benchmark for all Decware amplifiers that followed. This was the original Zen Triode Amplifier.

SE84C+ / Manufactured from 2008 to 2009. The chassis was stretched an inch, the larger world voltage power transformer became standard. The thickness of the steel chassis is doubled and the paint is changed to high gloss black powder coat.

The volume control was moved from the rear to the front. A second set of input jacks was added with a silver switch so you can run 2 sources.
Current model SE84C+ for 2010

SE84C+ / Manufactured from 2009 to 2012. The front mounted switches were moved slightly to make room for an upgraded volume pot.  Binding posts were upgraded. Finish was changed to a high gloss piano finish in white. Internally this amplifier now uses the CCE mod which stands for "Christmas Comes Early" and deals with improving the operation of the output tube suppressor grids.

SE84CKC / Manufactured from 2013 to 2015.  Known as the "SuperZen" the chassis has been improved again with a 1930's typewriter finish. By far the best sounding version to date due to a re-voiced front end. Each amp now comes standard with cryo treated beeswax caps. We named this update the CKC mod which stands for "Christmas Keeps Coming" which can be seen in the model number.
SE84UFO / JUNE 2015. Taking everything we've done to date the only possible thing that could be improved is the actual thing that made the amp sound so much better than it's competition... the output transformers. Decware SET output transformers set this amp apart with the ability to drive a dead short, and maintain flat response out to 20kHz. Now with our upgraded UFO wide bandwidth transformer standard equipment, it makes this amplifier simply untouchable.


This amplifier requires no adjustments or maintenance other than changing tubes every couple years. It is a self biasing design and self balancing meaning even unmatched tubes can be used without ruining the sound.  The SV83 (6P15P-EV) or EL84 output tubes wired in triode were chosen over 300B, 2A3, 45, and other triodes for having the best sound and imaging.

Weight   17 lbs. ea.
Dimensions   8.0" H x 6.125" W x 12.0" D
Circuit type   Single ended Class A Triode
Power output   2.3 watts  RMS 
Input voltage   2.0 volts for full output
Noise / Hum   Less   than 1.5 mV
Response   20 Hz ~ 80 kHz
Feedback   ZERO negative feedback used
Rectification   5U4G / tube rectification
Output tubes   SV83/6P15P-EV or EL84/6BQ5
Signal tube   6N1P or 6922 or 6Dj8 or 7DJ8
Transformers   Decware UFO
Biasing   Self-Biasing
Resistors   precision WW/MF by DALE, VISHAY
Signal Cap   Cryo Treated Beeswax Film and Foil with Silver leads
AC cord   Removable power cord
Consumption   65 watts 
Input jacks   RCA type 24K Gold / Teflon
Output jacks   5-way binding posts accept 12 gauge
Speaker dB/1w   89 dB minimum / 96 dB is ideal
Warranty   Lifetime to original owner

  (pdf format).

Watch what happens when designer Steve Deckert goes to take a picture of his new SE84UFO amplifier!

(warning some mild swearing in this video)

  2 watts per channel stereo or 6 watts mono

Hand Crafted in the USA and sold Factory Direct with a
L i f e t i m e   W a r r a n t y  !