In case you were sleeping:

The RKV was one of the original high quality headphone amps that were available back in the early- mid 2000's.  Headphone amp production was not as prolific as it is now, and was one of the few very good sounding options at the time.  How it compares to today's stuff I am not sure, but I remember the RKV as being very smooth, very full bodied warm sound, what some might say as being "tubey".  Its a nice amp if you can get it at a good price but I personally might pick something from today's market as headphone amps have gotten nicer.

It's nice. It's got a warm, pleasing coloration but it'll definitely smooth over details compared to the more resolving and neutral amps like a Zana Deux or the various Gilmore dynalo implementations, etc. I kinda liked how it took a bit of the harsh edge off the HD600. Also nice with the HD650 when you want to bathe in a warmer sound. Ridiculous amounts of power, so it offered superb dynamics for classical recordings - not that most headphone amps would run out of steam, but I remember classical just sounding really great on the RKV II. You'll need the optional impedanzer to run medium-to-low impedance headphones.

At the old used prices (~$700-750) it was a great nice buy for those looking for a warm sound. Been a good while since I had mine. The pricing situation may not be that nice these days.

A lot of people have heard this, as it was quite popular a few years back. I've owned two of them at various times. You need to be careful how old the amp is. The earlier ones have the transformer mounted on the board: not good when the amp is being shipped. Later versions had the transformer mounted to the chassis, which resulted in far fewer broken boards. The RKV itself will only drive headphones with 100ohm or higher impedance properly. It gets very noisy with lower impedance headphones, unless you use the Impedanzer (outbard impedance matcher).

A very nice sounding tube amp. Highs are rolled at the top, which could be why people report it as non-resolving.  If you do a search, you'll find that many people (myself included) have found a very nice synergy between the RKV and the AKG K-1000.  Also very good with Sennheisers.  If your primary headphones are low impedance, it's probably a good idea to look elsewhere.

That new silver version sure is a hell of a lot prettier than the previous gold/black - and I always thought even the old ones looked kinda cool! I agree with Hirsch, I only heard the K1000/RKV pairing for a few minutes years ago, but it sure seemed like a super match.

The RKV's, in my opinion, are a terrific amp (as long as you get it used) offering mucho amounts of power.  They're a headamp more for the "music lover" versus the "audiophile".  You'll say things like, "I don't care if this ain't neautral, it sounds so damn nice!" It'll allow you to just relax and enjoy.

The new ones, from the importer that quoted to price to me, is uber expensive.  Like three times the original's price.  Like, 3 to 4 grand range.  For that kind of money, you can definitely do better.  Too many choices.  But used, at a reasonable cost, well worth it!

Unfortunately, I don't have an Impedanzer for mine, but luckily ran across the EC/DC from Eddie Current, which seems to work similarily well.  The only thing is, with the one from AV, you could hook up the K1000 directly to the back.  On mine, I've wired my K1000's into a regular jack and am driving them from the amp, alone.  Still sounds very nice.

The new silver one is quite pretty; however, I think I still prefer the old black 'n gold models.  I've got a few amps, and if I had to let them go one by one, the RKV would be the last to go.

Im not sure if I have ever heard one, but the RKV is one of the comercial amps that still intrigues me enough that I humbly look at my bank account every time one comes up for sale.