Headphone Amp for Portable CDP

Since many of the better headphones IE Sennheiser HD 580 + 600 etc have impedance greater than 100 ohms, and most portable CDP have low output level to conserve battery consumption, an inexpensive headphone amp is needed for best sound. What amps are members using for under $400 retail?

Popular models include Creek OBH 11, Musical Fidelity X-Can 2, Grado RA-1 (battery powered) and various models from Headroom etc. I own Sennheiser HD580 cans and would like to run from portable CDP at home, any suggestions or recommendations for amp?
I use the HeadRoom Little but with a twist. I run the portable CDP first into a TDS Passive Audiophile unit and then into the Little. I recently saw the TDS unit for sale on Audigon for less than 50% retail and if you picked up a used Little, you would be under your $400 limit.
SM I do own a TDS Passive Audiophile now, and could not even
for a second think of removing it from my main system, but
I like your thinking! I am hoping to buy new/used amp for
$300 tops and was wondering how the Creek,MF,and Grado units
compare to Headroom units available for $300?

Any thoughts
The Grado RA-1 fits nicely into your price range and is excellent at driving Sens. Headroom will let you buy two amps and then return the one that comes in second during your audition. X-CAN is also good, and is superior to Creek at least with my gear, but I think the Grado is the best under $1K.
I enjoy my original version of the X-Cans with my 580s but the Audio Alchemy HPA-1 that I have is even better. It contains the Headroom circuit. The thing is class A and runs hot enough to grill toast on but the sound is quite liquid and defined. Super cheap used to boot. Good luck.
I use the Grado amp with a portable player, but with Grado phones. I thought I remembered the general consensus was that the Grado amp was not as good with the Sennheiser phones as with their models. I personally have not tried the combo. Good luck.
I run the Grado amp on both Grado RS-1's and Sennheiser HD 600's and it sounds great on both. The nice bonus is its portability (plus the conversation factor on airplanes!
I have a pair of Sennheiser 600's that I use with a portable CD player on the road paired with a Headroom Air head which was about 179$??? It's unbelievable to me how good the sound is for the money compared with the 18000$ main system. Great detail and resolution, good bass and non fatiguing sound...couldn't say if its that circuit headroom uses or not but it sounds good for the money. Also they were very helpful without being too self promoting.I also have an antique sound labs headphone amp that I've only used a few times at home that's not bad either but I just never use it when I am home. I read recently that the grado amp was designed by the same engineer who made the famous marantz tube amp and preamps. The idea was to make the grado combos sound similar which made me want to try it for that reason alone since the grado could travel as well. If you're interested in trying the antique sound labs amp let me know maybe we could work something out.
Happy Shopping
I run the RA-1 with a Panasonic sl-ct570 portable and Grado SR-80 phones. The sound is amazing. The RA-1 is a very neat little piece that is addictive on looks alone. I also have the Headroom airhead ($100) which is good, but not as good as the Grado - but hell, it's 1/3 the price. Although I've heard that the Grado will drive Senns I think you're better off going Grado with Grado, and take advantage of the built in synergy. Battery life with the grado's is about 50 hours. Headroom's new amps will have a 3 way gain setting which could be fun. They'll be out in a couple of weeks I hear.

If you don't care about the power cord, I listened to the Creek side by side with the Grado and it was very close, the Grado was a bit smoother(with Grado Phones) so that's what I went with.
Thanks for all the helpful advice!

I purchased demo Creek OBH 11 amp from my man JD at Audio Advisor, will use Headroom's mini/RCA portable connector cable to hook-up my portable to Creek, then my Senn HD580
will be driven by Creek amp. After hour and early morning
listening has new lease on life now!