Decware x ZMF Reference OTL

Decware x ZMF Reference OTL (Release date – end of April 2023)

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A huge thank you to Zach from ZMF for letting me spend some time with the OTL amp from Decware x ZMF!

This amp is one beautiful piece of equipment. This is something you would purchase just to look at. From the wood, to the VU meters, it is gorgeous. The amp feels very well built, which I wouldn’t expect anything less from either Decware or ZMF, and has quite a bit of heft to it.

It uses 1 x Input/Gain tube: 6922/E88CC (currently installed), 2 x Output/Driver tubes: 6N6P (6Н6П) (currently installed), 1 x Rectier 5U4 (currently installed).

This unit has 4 inputs (two 6.35mm and 2 XLR headphone outputs). You can plug 4 headphones in at once, so if you want to have a listening party this is the amp for you. I did not notice a difference in sound using just one headphone and switching between the 6.35mm and the XLR headphone outputs.

It outputs 1800MV in cathode resistor mode and 2000mV in cathode bypass mode. The switch right above the volume knob is what controls that. I noticed in bypass mode (moving the switch towards the volume knob) there was an increase in gain and a little more dynamics compared to the cathode resistor mode (moving the switch away from the volume knob).

It has 2 sets of RCA inputs as well as a set of RCA pre outs (closest to the transformer). The RCA inputs have little knobs near them that allow you to adjust the gain of the line in.

This OTL adds that layer of luxuriousness/lushness over the entire sound. It gives everything more of a thickness, especially the low end while not impacting any of the detail. It gives you everything you want in a tube amp without losing any clarity and transparency. This amp is a very easy listen. Just press play and get lost in the music.


Gorgeous looking amp and it sounds like it has a nice feature set as well. What headphones did you test on this bad boy and what was your favorite to pair with it?

Edit: And, of course, thanks for sharing!

I tested the ZMF Atrium open and closed, ZMF Verite open, Meze Elite, and Focal Clear MG. All the ZMFs sounded great but my favorite with the amp would be the Verite Open. It added that smoothness with a little thicker low end which I thought the Verite benefitted from the most.

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What dacs were you able to test with it, and anything at a similar level you could make a comparison to?