Merz Electric SVS OTL

October 2026

Here is an amplifier that I’m very excited to bring to my page, and that was sent to me this summer by the designer and builder Craig Merz. One of several unique designs that Craig builds at Merz Electric in Roanoke Rapids, North Carolina, this unusual power amplifier is a single ended OTL called the Model SVS. Built around the big Russian 6C33C tube, Craig’s design extracts 2 watts of clear and precise audio. An ambitious task to tame the mighty and difficult hand grenade sized Russian triode! But the result is exceptional. This is an amplifier that gets out of the way and lets the music and all of its impact, especially vocals, shine through. And Dear Reader, this was a case of knowing that it was right within the very first moments of hearing it. I don’t think there is much info out there yet about this wonderful amplifier, so I’m happy to be the first in what will surely be a long list of accolades.

So far I’ve owned two previous OTL (Output Transformer-less) amplifiers; Bruce Rozenblit’s Transcendent Sound Mini Beast and Roger Modjeski’s exceptionally fine sounding OTL-1. And now the Merz SVS makes a third. And of the three, this is the easiest to live with from a sense of all day or extended listening. OTL sound is usually very clean and crisp with mega detail and a sense of seeing into the recording. It can be exhilarating and immersive and even startling in its speed and detail retrieval. But it rarely feels relaxed. The Merz SVS OTL gets relaxed. And yet it still seems to have all of the OTL-ness of the other two I’ve owned. A rare thing I suspect.

An absolutely unique looking amplifier weighing a mere 10 pounds, the Merz SVS sees into the recording, with each part presented on its own little island, highlighted and very present. Vocals especially are somehow promoted by the amp and come forward centered and right out into room. It’s got a definite flavor; this is not boring or dull in any way. On a track like Diana Panton’s version of Quiet Night, Quiet Stars the layered performance is close to flawless. Paul McCartney’s voice on his new track Days We Left Behind clearly reveals his age and wisdom and the emotional transference is powerful. Natalie Merchant’s voice is engulfing. On Allison Russell’s Joyful Motherfuckers the opening slap of the guitar is almost startlingly realistic. Both vocals sound crisply defined and full of life and emotion. Her French is delicious. Just a spectacular portrayal of a simple take like this. The SVS makes this type of relaxed program material sound fantastically real and present, and engaging as hell. And all with no drama. There has been no hum or hiss or naughty issues of any kind in the 50-60 or so listening hours that I’ve put on the amp so far.

The SVS lacks its own volume control unfortunately, so it needs a preamp. I’ve tried several; my trusty Bottlehead 6AV11, a Schitt Saga passive and a Luxman LX-38 integrated used with it’s pre-out functionality. Overall, I got my best sound with the passive Saga preamp, and I feel like I’m hearing what the Merz really does without any embellishment. Although at only 2 watts the dial on the passive is often almost (but not quite) wide open. Configured this way the Merz has a lot of space and placement, with deep bass and the clear insightfulness appropriate to an OTL. The OTL sound is about purity, and having a powered preamp cluttering that up defeats the purpose I think.

A product like the Merz SVS OTL certainly resides in an outer suburb of the hifi world. With an abruptly industrial look, only 2 watts per channel, and using a tube that puts out a fair amount of heat (although overall the amp runs quite cool), the SVS is certainly not going to be for everyone. But for those who explore the possibilities of 1 or 2 watts on an efficient speaker, this is perhaps the best value for dollar current production amp that I’m aware of. And in all honesty, if the SVS had an onboard volume control it could probably replace most any of the single ended amps that have come through my room. Recently I’ve been coveting a Toshi Kurashima 2A3 integrated that will appear in more detail on these pages next year, thinking perhaps that it could be the one Reference to hold on to and settle into for the long run. But fidelity-wise it could very well be a wash between the Kurashima and the Merz SVS. There are some flavor differences of course, but the Merz is certainly not playing second fiddle. With long lines and multi-year wait times on amplifiers like the Decware that I’ve recommended in the past, the Merv SVS is a solid choice that I would not gamble against in a back to back shootout. If you can provide the right speaker, this is sound quality that you will be very hard pressed to better in any meaningful way. Thanks to Craig Merz for the chance to review a masterpiece. Super highly recommended.

This amp has an absolutely uniue look. This is a big, rich sounding amplifier! An OTL that has a bit of syrup, what’s not to love?

RCA 5963 input tubes.

The unconventional looks of the Merz SVS have definitely grown on me, and with the bright glowing 6C33C tubes it has some real in the room presence and gravitas. Being able to lift and move it so easily is also a big plus. 40 and 50 pound monsters have somehow become a norm around here and the light weight is almost a revelation.

The 6C33C is such a fascinating tube and it’s hard to argue with the cool looks. In a previously owned single ended amplifier I found the 6C33C to sound dense and powerful, like a boxer. And while not hard in any way, it wasn't quite as emotionally engaging as I like. In the Merz SVS the 6C33C is more nuanced and a little less saturated, and overall a little lighter on its feet. More like a gymnast.

Here with both the Yamamoto A-08S and Toshi Kurashima 2A3 integrated, both equipped with end game old stock tubes. The SVS holds its own in this company, what more can be said?

I recently acquired a Luxman LX-38 Ultimate integrated amp, and have used it for a few days as a preamp feeding the SVS, and that has worked very well. But the Luxman has a lot of inherent dimensionality and richness to its presentation, and it changes the sound of the SVS into what ultimately sounds very much like the Luxman’s own power amp, unsurprisingly I guess. In the end I liked the Merz SVS best with a Schitt Saga passive.

I’ve enjoyed the Schitt Saga more than some of the other Schitt products I’ve owned so far. The Saga, especially with the tube engaged, has a nice open sound, and once I got used to the annoying switched volume control its been reliable and seems to get out of the way. With the tube engaged I guess it’s not completely passive though. On a side note, I’ve been using the Metrum NOS DAC pictured here for about 5 years now and I see no need to replace it.

The Merz SVS is top shelf sound for sure. My amp isn’t going anywhere!