I have been writing this forever its something between a review and impressions but more of the former
GRADO RA-1 Headphone amp
About the amplifier:
Grado RA-1 stands for Grado Reference Headphone Amplifier; my version is the one that uses two 9v batteries, which I find very handy because now I have a powerful transportable amp and the rechargable 9v batteries last for a reasonably long time (sometimes as much as 10 hours). There is also a version that runs off an A/C adapter, both have enough power to amplify about anything thats not too power hungry with authority. Theres also evidence of 9v battery versions with a very low gain, but I think those are very rare.
TL;DR:
It provides “Grado Sound” for sure, and is also made to match up with Grado headphones, but in reality is a macrodynamic focused amp that works well with a variety of headphones, it feels very random what it does to the staging but its mostly positive in a fun way.
So with this neat and light mahogany box I can give my headphones a vast array of and for grado qualities such as sense of warmth, treble control, mid-forwardness, sometimes focus on depth or soundstage size, smoothness in general and/or macrodynamic impact. It really is pairing dependant.
Build and user experience
The build is fantastic, everything is sturdy and has not a speck of rust to it, the aluminum knob is good, the amp is very light (over half a pound) and nice to handle, but very resilient:
Recently it fell of my hands from a tall height, it literally sounded like a skateboard landing, nothing broke, no dents, just a small scratch, its working perfectly and sounds the same.
The mahogany needs just a touch or two of coating to look like new, right now it has an old furniture finish.
The headphones pop while turning the amp on and off, just like on the RNHP but not as loud (AFAIK just plug the headphones after powering these amps and unplug before turning off)
When the batteries are full it has a dead silent background, as the batteries start to run out I get brackground noise, its not annoying to me, I just let it be as I find it the type of white noise that is actually not distracting and even relaxing, its quiet most of the time so that my ears digest it quickly and I stop hearing it.
Impressions by comparison
Im going to be comparing it to the popular and reference amp that is the RNHP, M0N describes it better than I could.
The RNHP is a very tough opponent, but also very good for comparisons as it has a studio-ish tuning. Will this old mahogany box be able to compete with such a modern classic? spoiler, yes.
I used Pro-ject prebox S2 DAC in every comparison (cause all my other dacs suck as of writing), its transparent, reminds me of a bit of the chord mojo.
My sonic preferences
I like bright sound signatures, I love all of the headphones used below, female vocals/piano/flute/violin and drums/percusions are the instruments I like the most, and I listen to an ample variety of common and rare music genres.
I look for, over other qualities:
Fordward and/or intimate presentations
Good dynamics (and dynamic range)
Good instrument separation and staging
Sparkly, shiny treble
Punchy bass, both the dirty/rumbly and clean/linear variations
Headphones Comparison
My scoring system is intentionally very subjective. (depends heavily on the mix & master of the songs used, and your chain):
It may be very close or very far away from your taste, use the descriptions instead of the rating for a more accurate representation of the amps’ sound.
Emu teak with bamboo cups
RNHP -Incredible detail and resolving capability, great layering, full sounding and tonally dense
RA-1 -BIG Macro dynamics focus, Huge soundstage, boomy and strong bass, smoothened treble, just very fun
My Enjoyment
RNHP: 8.7 GRADO RA1: 9.4
Audeze Sine with Nighthawk Pleather Pads
RNHP -Transparent, Scales very well, better texture, slightly better timbre, bass is sweet and organic just like candy, superb staging, enjoyable guitar crunch, uses all of the stage to create a full bodied sound.
RA-1 -More bass and midrange emphasis, sounds just as full and sweet, bigger soundstage, I didnt feel like I missed any detail (Lo-fi and Hip hop were tested, so nothing too complex).
My Enjoyment
RNHP: 8.4 GRADO RA1: 7.7
Audeze LCD X pre 2021 No EQ
RNHP -This is a very popular pairing, very detailed low end, powerful midrange, dense and fast sounding.
RA-1 -This combination sounded similar actually, almost as good, but the RNHP leads ahead with its resolving prowess and better tone.
My Enjoyment
RNHP: 9.7 GRADO RA1: 9.3
Focal Clear OG
RNHP -This is, at the moment of writing my favorite chain, it does everything in an ejoyable and extremely resolving way. Not much else to say.
RA-1 -This is a great pairing as well, amazing pairing actually as clears picky, just not legendary to my ears like the Neve combo is.
Mac’s personal Enjoyment
RNHP: 10+ GRADO RA1: 9.3
Grado Hemps (flat pads)
RNHP - A lot of people like this pairing but its not my favorite, I find its combination of frequencies not the most pleasing with these amp, although it is quite detailed and has great grado bass
RA-1 - This completely leaves the Hemps the way I like them, more macro fun focused, better vocal/instrumental timbre to my taste, it now sounds more like an actual grado.
My Enjoyment
RNHP: 8.3 GRADO RA1: 8.9
Grado RS1 (g cush pads)
RNHP - This really brings the RS1 to the 2020s, it can bring out some great detail and timbre from these classics.
RA-1 - It has great tonal synergy with the phones but I really miss the micro detail and accuracy that the RNHP provides, also it sounds less dense.
My Enjoyment
RNHP: 9.4 GRADO RA1: 9
Beyerdynamic T1.2 with ad2000 pads (makes them intimate and warmer)
RNHP - The nuance, musicality, body and detail on top, its way too pleasing.
RA-1 - Its just has not enough power or detail to make these shine, not even on the vocals. Volume is not a problem at all tho.
My Enjoyment
RNHP: 9.1 GRADO RA1: 7.5
Audio Technica wp900
RNHP - I love this combo, it has all the subtleness (?) that the wp900 need, creating a very different and special way of listening to music.
RA-1 - Still good, but with the subtle part gone it just lacks refinement, even though it sounds similar in presentation.
My Enjoyment
RNHP: 9.2 GRADO RA1: 8.3
Closing thoughts
These can sometimes be gotten for cheap, I love to have gotten one as I thought I would never use it but its a very fun amp that genuinely surprised me with how unconventional it can sound; I think you could put it beside an asgards 3 and it would definitively hold its ground with different signatures, also having a dedicated lightweight wooden portable amp just feels cool.
@NickMimi you dont rly need it, but its a cool device for sure