Well...about the RA1. First of all, I am by trade an EE. I no longer work as such, but I know what I see.
So yeah, that's my RA1....
It is very basic, I know. But there also some interesting design choice, for example the coating each small "box" has. No one sees it, yet they done it (I bet manually). Batteries have a cloathed box. And that big cap is actually an input cap, not even the power supply. You could say it is fancy cmoy in a mahangony box, but then why go the extra mile and do all these things nobody see? Plus I bet they selected all the components very carefully and by listening. No cmoy which I heard sounded remotely like this.
But all that does not matter, how does it sound? I have to add, the I have in house right now the Trafomatic Head 2, the the TMP Ant (with external PSU), and the Enleum 23-R. I also had the Tor Audio Balanced, the Pathos Inpol Ear.
For Grado (and strictly for Grado) the RA1 is at the same level as the Enleum (with different presentation) and better then any other on list. I was suprised too!
It simply makes the music involving, an experience, no just pretty sound. It can be raw, but in the absulte postive way. Because it is at the same time smooth, but much more direct as the Enleum. It is really like a Grado Headphone in amp. An example is this track:
Enleum + whatever headphone: nice, sound, for sure, but why would I listen to the end of this track?
RA1+GS3000e. Magic. The notes have such attack, dynamic...you are just there, you are almost part of the performance. Much bigger space too. You feel every note, the energy, the intention behind them. Captivating. I listend to this album (2 hours!) the 4th time in the last two weeks. It's like a Tarantino movie feeling, hard to describe. Yesterday I showed this track to my wife too. First with the Enleum + HEMP. Then with the Enleum + GS3000e and then RA1 + GS3000e. She also had an immidate reaction to the third combo. I tried to explain before this "magic" for her. She just said: yeah, I understand, totally. Much-much better the the others.
With the the other amps I wouldn't have listened to this song a single time.
Now, the RA1 ist not universal. It is just for Grado and for me it is best with GS3000e. Then also very good with the classic RS1 I have. HEMP...somehow not. Meze Liric was absolutely terrible wrong with it. Plus it has way too much gain, you use the pot very down low, which often leads to channel imbalance. But for the price you can have it (if you use a Grado) it is absolutely unbeatable I think.
And I am not exactly alone with this...