Because of changed living conditions, I will have to make use of my old, but hardly used headphones again. They are AKG K400's
They will be used with my hi-fi set: record player, cd player, radio-tuner, cassettedeck and integrated amp.
The amp (Sonneteer) has no possibility to connect headphones directly, the CD player also not. The only possibility to connect headphones in my system is my Teac cassettedeck (yes, I am THAT old.... ).

That's why I started a search for a decent headphone amp to feed my AKG K400.

I made a (short)list, based on price and lots of reading here and elswhere:

Budget:
Pro-Ject Headbox II
Firestone Cute Beyond

Some more €€...:
Pro-Ject Headbox SE II
Creek OBH-21 or 21 SE
Graham Slee Novo
Meier Corda Swing

or even €€€...:
Heed CanAmp

I have no idea which one would work best, could you advise me...?

I've not heard all of them and have never heard the K400's, but I'll try and offer what I can.

First off is to decide how much each improvement in sound is worth to you. Will cheap and good sound do, or will you pay more for very good/great sound? Next is do you anticipate upgrading the amp anytime soon.

I bought a Creek OBH-11 as a stop-gap when I had to give up my speakers for a little while and got a better amp when I knew I was going to be stuck with headphones for a few years. If you are like me then you will start looking for something better than the cheaper amps after a little while.

Quote:



* - I've only heard on extended demo in shop.

If I was in your position I would get the GS Novo or CanAmp and depending on your budget I would look at the GS Solo. The CanAmp feels much more expensive, better built and looks nicer than the GS amps. That said the GS amps are very well built and are smaller.

Thank you Stoin!
In the meantime I eliminated some amps from my list, but of course also added (only ) one new candidate.

Here is my short(ened) list:

Graham Slee Novo
Meier Corda Swing
Heed Canamp

and added: tubes....

Little Dot Mk3 (or Mk4...?).

Anyone with a good advise for me here?

I think any of the amps on your shortlist should make you pretty happy they are all well regarded and the two that I have heard are both very nice sounding. The problem with audio gear is that there are always a few products that will do what you want and picking between them is usually incredibly hard.

Good luck with your decision making and hopefully the one you get will serve you well.

It took me quite some time to decide, but I just ordered my headphone amp. Not one of my shortlist though. It will be an OTL, made by a small Polish firm: White Bird Amplification. ( www.white-bird.pl ) They only produce head amps, and only OTL's. I am afraid they are rather not known abroad...   The website is only in Polish, but is nevertheless interesting, I think. Have a look under "produkty".
 
The pictures and descriptions will be clear anyway.
 
 It will be the HPA-03 Reference (yes, on a budget  , 700 zl. = about € 180,- or $ 240,-).
When it arrives I will let you all know how it makes my old K-400's sound!

Almost 3 weeks ago my WBA HPA-03 Reference arrived.Yes, the production took a month, the guy builds them on order....
After unpacking, my first move was to connect it to the line out of my Sonneteer amp and switch power on. The next step was selecting a number of bass-heavy songs on "Anouk is alive", a great live rock cd, and connect my AKG K-400.
And than let it play... a few hours at low volume, the next few hours at medium volume and about 24 hours at high volume. This should be enough, I thought, for the "resurrection" of the K-400, bought in 1994 but still as new, not more then 20 hours and not used for at least 13 years.
The White Bird tubes also got used to labour life this way...
 
And now... how does it sound after a few weeks? Who says K-400's have no bass? A serious, solid and tight fundament, clear and open mids and great airy highs without harshness (OTL amp...?) The soundstage is also pretty good.
Music just "flows". It is fun when it is to be fun and intimate when it is supposed to sound intimate.
This combination sounds great, mainly with my favorite menu: jazz. Extremely musical, fluid, lifelike. Listening to "Jazz at the Pawnshop" (vinyl) I just got shivers... Sara K, Norah Jones: stunning!
This AKG handles classical music well, it doesn't get lost in complex big orchestral works. Rock sounded surprisingly fullbodied and controlled. With BASS...!!!
 
The old K-400, fed by an unexpensive OTL just sings and is in my view a real stunner!