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All DECWARE products are made in the USA

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Hand made in the USA and sold customer direct with a lifetime warranty!
Available in 120 or 240 volts.

Make Your Source sound twice as good as it does now!

The Secret
to the Z Stages
ability to make such a giant difference in the sound quality of your source... is its gain

By turning it up to 4 or 5 volts and then turning your
or amplifier down to compensate, you will add great weight, punch and overall power to the presentation... the kind that's just not possible with a standard 2 volt source.

If that wasn't enough, it also has a switch on the front that gives you two distinct signatures - one is a more laid back setting, the other a more aggressive setting... it's like having two different sounding stereos at the flip of a switch.

And the final icing on the cake is the tube itself.  Since no two brands of 12AU7 sound the same, you can do a little tube rolling and find something that personalizes the sound of your rig even more.

So you want a better sounding source?

Take your present source somewhere and have it tweaked, modded or upgraded for maybe a 10% improvement...


Buy a brand new source that costs twice what your present one did and hope for a 25% improvement...


Keep your present source and add a ZSTAGE to it for the biggest noticeable difference in sound of all three options, by far.


The ZSTAGE is a single-ended triode stereo gain stage.  It uses a single tube operating in class A with no negative feedback.  It accepts any standard 2 volt line level source like a CD player or DAC and has a variable output via the front mounted gain control.  It can also be used as a purist tube preamp where multiple inputs are not needed. 

Designed for 24/7 operation it is always on, and always warmed up and ready.  The lower voltages that make this possible aren't even enough to get the tube hot to the touch.  It does however greatly lower odd-order distortion and increase even-order harmonics making everything sound better.


The ZSTAGE features a black powder coated steel chassis with a standard IEC connector and removable power cord.  No circuit boards, Hand Made and Available in 115/230/240 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 slightly warm operating temperature for best sound, the ZSTAGE 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 output 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 and drive most amps directly.

A font mounted switch allows you to adjust the operating points on the tube causing two different signatures; One is extra dynamic and full, the other is more laid back sounding. A valuable voicing tool to find the best compliment to your system, it also lets you hear any tube you put in it sound two different ways.

A very good description of how to use this and what it can do for you can be found in the owner's manual.


A final advantage to using a ZSTAGE is the simple fact that you can tube roll with your choice of   12AT7's or 12AU7's.  Each of these tubes have a different signature as does every brand of each tube so you gain tremendous control over how your system sounds by voicing it to your tastes.  Since the tube sticks out the front it can be easily changed at any time.  Expect about 5 years on the tube before replacement.  All tubes come with a 90 day warranty. The unit will ship with a 12AU7 because it's generally the best sounding of the two.


The ZSTAGE is self biasing so you NEVER have to set or adjust the bias for the output tubes.  It is a maintenance free design.


Of course there are no circuit boards and no Chinese parts evident by the lifetime warranty.

Internally the ZSTAGE uses top grade resistors and poly film & foil capacitors on each channel.  The output level control is made by ALPHA, internal wiring by MOGAMI. Voltages are low for tube gear so the tube lasts for many years. 

The purist signal path consists of 1 resistor and 1 film & foil capacitor and a perfectly straight solid copper ground between the jacks and the tube.

inside view


This amplifier is hand built in the USA by DECWARE / High Fidelity Engineering C0. 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.


You may read reviews on our products here.


Weight   7 lbs. ea.
Dimensions   2.5" H x 6" W x 11.0" D
Circuit type   Single ended Class A Triode
Gain   Adjustable from 0 to 15 volts with a 2 volt source (17.5dB Gain).
Input voltage   5 volts max
Output Impedance
<1000 ohms
Input Impedance
47 K ohms
Noise / Hum   -80db V / -62db V
Response   10 Hz ~ 90 kHz
Feedback   ZERO negative feedback used
Rectification   UN4007
Signal tube   12AU7 or 12AT7 
Transformers   Decware
Biasing   Self-Biasing
Resistors   precision WW/MF by DALE, VISHAY
Signal Cap   Polyurethane Film Caps or Beeswax Foil Caps
AC cord   Removable power cord
Consumption   13.5 watts at the outlet
Input jacks   RCA type 24K Gold
Output jacks   RCA type 24K Gold
Warranty   Lifetime to original owner


ZBOX - Tube buffer stage that has no gain.

Works to enhance any CD player or DAC
with a standard 2 volt output

Rear View

1280 high res image



Hand made in the USA and sold direct to the customer with a lifetime warranty!
Available in 120 or 240 volts.

Customer Comment ~ August 2014


I picked up the ZSTAGE last night from UPS. I got it hooked up immediately (I read the owners manual many times over after I placed my order), and my first impression-and my wife’s-was WOW! This ABSOLUTELY fixed my volume problem! She told me “Wow! Now you get that same elegant sound and more of it”. She is right on the money.

I have been playing with it last night and this morning-doing a little “riding the gain”, which seems to me that you can tailor the high and low end. If I crank up the Z and also crank up the SE34 I can get low end that is HEAVY but it seems that I lose a little on the high end. I have the Z about 3/4, maybe a tad more, and the SE34 about 1/2 way up and, well, the volume is plenty and everything sounds balanced.

What really was a surprise was that by turning up the ZSTAGE and using very little volume on the SE34, so listening at lower/normal volumes, the sound is complete-it is not lacking on the low end at all, which it usually would be at low volume in my opinion without the ZSTAGE.

As a side note, I still had some weird distortion problems that I thought were related to grounding issues with the turntable. Here is the strange part-I took the Clearaudio cartridge off the turntable and put on a different one I had around and the problem totally disappeared. I think something has gone wrong with the cart. I was using.

I am totally happy with the ZSTAGE! Now I can listen at volumes that I want and I think my whole system sounds better at lower volumes as well.

Seriously, why wouldn't’'t everyone want to run one of these? You don’t lose anything and you gain so much (no pun intended) that I don’t get why everyone wouldn't'’t use one. I will be holding off on a Torii or ZMA at least for a little while now, but I will tell you one thing for sure-I will only be buying audio gear from you from now on. My next amp will be coming from you. I will also be getting more interconnects from you. I’ll be getting everything that I can from you. And yes, when I make the jump to a MC cartridge, I’ll be getting the step up from you too. My wife actually said last night, after seeing the interconnects you sent, “Those are cool. Why don’t you have more of those?"

Thank you for all of your help! Now, since I took the day off to specifically play with this since I knew it was coming, I am going back to playing some records! I know this email is probably a little garbled and possibly hard to understand, but I am really excited.

Thank you!