Finding the Oppo ha-2 is nice, but out of my price range, trying to find a warm SS portable amp, for low impedance Grado cans, do not mind if it's out of my iPhone's headphone jack, I'm just looking for something that could warm up my Grado's slightly. I am a treble rebel, for sure, and I love the strings and guitars out of the Grado's but at times, I would prefer slightly more warmth. Any recommendations are appreciated, budget of about $100, more than happy to buy used.
The thing is the reason why I'm saying you transmit a digital signal is because the iPhones are generally neutral,
but their distortion pattern may be to lean out; hooking up a high impedance amplifier input to that same output off a phone can result in the same problem, and the
amplifier will just end up
amplifying that same signal - as opposed to deliberately changing it, in which case instead of
amplifier it would be more apt to call it a
euphonic boombasticator - and therefore still give you a still thin/bright sound, but this time maybe the increased current will preserve bass hits better. It would probably be easier to achieve your goals by getting an RS2e and use the closed earpad on it, or something like the Garfield earpad cover.
However that is way over your budget even if you sell the SR325, and even then you'd likely want to have it recabled (you'd miss how easy it is to use that cable you have now vs the thick and somewhat stiff cable on a stock Grado), so you could probably try to track down an original Fiio E7. Not the E07, or E07K, just the plain E7 - that was warm enough to be easily noticeable.