So where do I begin? I say this because my file with my impressions was lost when my  Dell computer took a dump a while back. I have since transition to an 21.5 iMac so I am having to do a new write up of the Isabellina HPA ( http://www.redwineaudio.com/products/isabellina_hpa ) and the Signature 30.2 ( http://www.redwineaudio.com/products/signature_302 )
 
My first Isabellina HPA was purchased in the summer of 2009 right after they became available and I enjoyed its sound tremendously. So much that I sent it back to Vinnie to have it modded to provide power to a Wadia 170i a combo that brought a lot of smiles and good times. Note: I had Ken of ALO ( http://www.aloaudio.com/ ) build me an IC to provide the power from the Isabellina HPA to the Wadia 170i.
 
However, at the time I chose to move into a different direction and sold that set-up. This was a decision I soon regreted, specially when I got my first AKG K1000. So off I went and bought a second Isabellina HPA and it is my source to the Signature 30.2 which I use with both my AKG K1000 and an Stax SRD7/Pro modified by Birgir (spritzer) which in turn drives an Stax Lambda Pro also tweaked by Birgir.
 
Currently I am feeding the Isabellina HPA via an USB cable from the iMac, I have found no difference in sound perhaps an slight advantage to the USB in smoothness and in the ability to draw you in to the music. This may be placebo or not, suffice is to say it is my preferred method. Needless to say I am using Apple Lossless files and iTunes. BTW, I am using a pair of Signal Cable’s Silver Resolution with silver bullets 2 feet long between the Isabellina HPA and the  Signature 30.2. You can read more about them at: http://signalcable.com/silverresolutionanalog.html
 
I do not expect this to be a full impression report since honestly the best evidence of how much I like the sound is in the fact I re-purchased the unit. Not only that but currently I am in the process of securing the funds to upgrade the unit to an Isabella w/ Isabellina and HPA. However there are some elements of the sound presentation that I will discuss, hopefully they will provide a frame of reference and although I realize we all hear differently and have different headphones, music, and expectations it will be useful.
 
There are certain words that come to mind when listening to dynamic headphones via the headphone out of the Isabellina HPA. These are: Engaging, from the first note the sound grabs you and does not want to let you go. I guess another way of saying it is Musicality, the sound is very pleasing and its presentation makes you want to stay tuned for the next song and then the next song until you realize  you have been there for hours. I could go and use all the words you see in reviews/impressions like punch, detail, clarity, impact, soundstage, depth, etc. Although they all apply I truly feel that engaging and musicality cover it.
 
Next would be the Signature 30.2 and that is one beast of an unit. It is hard to imagine that such a simple design can deliver so much but those two 12 volt SLA batteries can provide a lot of amps when needed for a music transients. I find the K1000 response is extremely fast yet it never gets harsh or wanting. Similarly for the Stax energizer, which I was extremely surprised how good the Lambda Pro sounds. The word that first came to mind was involving. Yes, I am sure a Blue Hawaii and other high end amps would sound better but I do not have one so I can not compare them.
 
Here are some pictures.