what do you think about this one:
Do see a fair amount of specifics in the PDF: http://www.nixiekits.eu/Downloads/MiniHeadphoneAmp_Aufbauanleitung.pdf And the stuff up on that site looks pretty good & solid to me.
I've too many tube hybrid headamps, so won't be trying one, but the idea of a SMPS (555-based) HV seems interesting to me. I'd tried to get something like it going using a modded off-the-shelf nixie SMPS but could not get around some noise issues... Probably could have cleaned it up but it became more trouble than it was worth (for me).
Do see a fair amount of specifics in the PDF: http://www.nixiekits.eu/Downloads/MiniHeadphoneAmp_Aufbauanleitung.pdf
Schematic is on the last page of this build manual.
I ordered the combo of both the amp and vu meter. They come well organized with PCB's and parts seperated in to little bags keeping them tidy. The build of the VU meter was very easy and took about 1.5 hours from start to test run. I decided on the stereo EM83 VU tube and the green glow is very pleasing.
The headphone amp was more time consuming to put together for me since it had been a while since I soldered. I also wasnt trying to assemble it "fast" but to look nice when completed and to not make any mistakes. I have to say that the kit went together very smoothly. The case and presentation is very nice and it looks great sitting on my desk. Now to the sound. It's rich and buttery. I'm very impressed with the amp and the sound produced. Plenty of power to drive some power hungry open air headphones. The low end bass and mids sound fantastic.They look great sitting side by side and the LED's with the glow of the tubes is great in low light. The price may be a little more than other kits out there but I'm very happy with it over all and the matching case makes them look great. I would reccomend to anyone interested in a very nice tube PCB headphone amp.
Torn between resurrecting an old thread, and starting a new one when there's a perfectly decent existing one...
I recently bought a pre-built one of these (in a very tasteful mirrored blue) and will write a full review at some point when I've had a proper chance to burn it in and listen to a wider range of music. There seems to be a dearth of reviews of these little amps out there on the net, which is a great shame - because they are really great little amps, and they come in at a sensible price for those of us in Europe who would probably get clobbered by import duties and taxes if buying American-sourced (or the more expensive Chinese) valve headphone amps.
Despite the lack of reviews, the information on Juergen Grau's www.nixiekits.eu website was enough to make me very interested, and I pinged Juergen a few emails with some questions about the amp and some of the design decisions he'd made in the design - which he answered very promptly, courteously and in good detail. That was enough for me to take the plunge - amplifier ordered on Saturday evening - arrived on my desk at work on Friday morning. It was a long day - waiting to finish my work, get home, fix a meal, and PLAY!
My pre-exising rig comprises of an Arcam CD62 CD player feeding into a Bravo V2 headphone amp, and driving a pair of venerable Sennheiser HD420SL headphones. A setup which gives very enjoyable, relaxed listening - though the (stock) Bravo is a bit reticent in the treble department. The Sennheisers are due an update (my wife has bought me some Sennheiser 598s for Christmas - but I'm being patient) - but I'm very familiar with the sound they produce - so for me at least, they are a known quantity.
Swapping out the Bravo and putting in the Nixie was a revelation. The soundstage was immediately improved - breadth, depth and solidity - instruments had a real location and presence. And then there was the detail... not detail in an intrusive "hi-fi" sense, but genuine realism - a sense of coherence and air in the recordings, and not in a way that gets in the way, but quite the opposite - that simply lets me enjoy the music. I was listening to a CD of Ulrich Schnauss (I don't recall which) last night - and it's a recording which I find hard to listen to sometimes - there's almost too much going on and it's difficult to unravel the threads sufficiently and hear the music - the Mr Nixie amp opened it up enough to make the difficult passages comprehensible and even enjoyable. I could try to describe the quality of the bass, the mids and the treble, but I don't really listen in that way, but what I can say is that what I hear through this amplifier (from good recordings, at least) is engaging, believable music.
So in a nutshell, I think it's a great little headphone amp - the miniature Russian valves look really cool. The only downside is that they're not really amenable to tube rolling, but when the amp sounds this good, I ask myself, why would I want to? I'd rather spend the time just enjoying the music.
I'll post up some pics and further thoughts when I get the chance.
Thanks for resurrecting the old thread. Otherwise I never would have seen your posting
Actually, it's the opposite. They are specifically not microphonic - they were designed by the Soviets for military applications, and ruggedness and non-microphony were very much part of the design requirement.
Here's a link you may find of interest...
However I believe that these tubes are used in some Neumann microphones which use a small valve amplifier integral to the microphone housing to boost the signal for use with long cable runs - such as in concert halls and the like.