Nikola Nikolov Single Ended EL-11

Here is an interesting little amplifier that landed on my doorstep recently, a single ended EL-11. This was made by Bulgarian-born builder Nikola Nikolov, currently living in the Baltimore area and selling his hand crafted amps on Craigslist. It was loaned to me by one of his customers to demo and provide some feedback. So in the interest of disclosure, unlike almost every other amp on this page, I do not own this one. More of Nikola’s builds can be seen on his web gallery page here.

The EL-11 is not a tube I had ever heard of, but it turns out to be quite a sleeper. A very early German pentode, the EL-11 makes 3-4 watts of power in a single ended circuit like this one, and it has a very articulate and direct sound profile. This little amp has some guts!

Sounding a bit like a mix of the 6V6 and the 2A3, this has both some pentode and some triode goodness, overall very nice. In play the word “crisp” kept coming to mind. This is not slurred and blurry sounding in any way; space and overall delicacy come shining through. Piano key strikes are clear, drums and percussion instruments have clear tones and ambience, and vocals have the “you are there” quality that good single ended amps are famous for. Overall this little amp is very clean and alive sounding, with an almost thoriated tungsten glow about it.

Unfortunately, build quality on this one is rather low; the whole thing has a thrown together feel and one has to wonder how it survived the trip through the postal service to me. But it did, so I guess that is something. Many of Nikloa’s other builds seem to be at a higher assembly level, so perhaps this is one an anomaly. Parts used here are a mixed bag, although the small RFT output transformers are probably of very high quality. They almost look like something from a microphone amplifier, the kind that these days get repurposed into moving coil step up transformers. There is a small amount of background hum, but once music is going it is not objectionable.

At any rate, build aside this amp is a success where it matters; its sounds wonderful! I would be very interested in experiencing another EL-11 amplifier built onto a stronger platform and with top-shelf parts and attention to detail. Tube amp builders take note; here is a tube that is way off the radar but is definitely worth investing some time and design into.