Tube buffer?

I built runeight's bootstrapped buffer which is a unity gain buffer designed around the 6922. It works as it was designed to. I actually built an early version of the final design and it does not have the servo. If you want more info on this buffer, I would post on the other forum or pm me..dB

edit - I use it as a buffer between cdp / amp not to drive headphones as a Szekeres would be used.

http://headwize.com/projects/showfil...=cmoy5_prj.htm
This is very good headamp,
http://headwize.com/projects/showfil...bender_prj.htm
This I like beter - the same on my favorite 6n1p
If you feel, you realy need only buffer, try only White cathode follower output stage. For low impedance phones this is the best OTL topology.
Zigis.

The only tubes that will come close are things like the 6AS7/6080. They are still not quite there, but they have so much power that the inefficiency of a highish output impedance is not the end of the world -- you just lose a lot of power as heat which is not a big deal. There are, however, two (or three) primary problems with the design: 1. these tubes just are not that great sounding, 2. there is a big electrolytic in the signal path on the output , and while you may be tempted to use a low voltage highish quality cap (like a Muse or Blackgate) if the tube were to short internally, you would then have a loud bang that could blow your eardrums/head[phones and/or a high voltage across your ears which is, in my opinion, not worth the risk. There is a third problem as well, which is that cathode followers inherently don't sound that good due to 100% negative feedback -- that is, compared to a single ended design, the cathode follower will kill the sound.

But, if you want to build a high quality, cheap, single tube amp with low output impedance that is designed for Grados and that has low gain, and zero negative feedback, then look at the Less-pressivo. The Grado version, using Hammond 119DA output transformers and perhaps a single 6h30p or 6N6p is a very good amp that will frankly embarrass most of the sub $1000 amps out there that are generally recommended for Grados.

You can PM or email me and I'll be happy to get you started in how to assemble one of these, but really it's a piece of cake.

-d

cathode followers inherently don't sound that good due to 100% negative feedback -- that is, compared to a single ended design, the cathode follower will kill the sound.

White cathode follower haven't this problem, have lover output impedance and more curent. For low impedance phones 6h30p or 6N6p in White cathode follower is especialy good. Large output el caps need to be bypass with polpypropylene.
Zigis.

I have the fortune to obtain the tube buffer built by dBel84 (runeight's design). I am hearing an improvement in my system: Gamma2 Dac --> tube buffer --> M3 amp --> DT770 / 32 ohm. The tube buffer extend the soundstage, fills up the mids and make the highs smoother; without the tube buffer the combo was a bit aggressive with dance / eletronica type of music. I am not a DIY guy, but I think this tube buffer sounds really good and specs well (re: output impedance is mostly 150 ohm.....that is low enough) at the same time. Thanks for the great job,dBel84 and runeight! This tube buffer is so good that I am thinking to get another one......but I do not know who else can build one.