Hello, I was directed to this thread by mironathetin who had found that I own both the Earmax Silver and the Leben CS300 and is asking for my point of view. I think that both are very good amps but with a clear advantage for Leben if you compare. Still they share many characteristics and I regard them as having a similar sound profile. Both capture the essential musical content and avoid the fallacy of being super-detailed. Both are fun and satisfying to listen to. You can adapt the sonic profile for both by changing tubes so it is not easy to exactly describe how they sound. The advantage of Leben is that it is more controlled and gives more weight and power to the presentation. It feels more present with better soundstage. With regard to the difference in size the Earmax keeps up surprisingly well, although the advantage of the Leben is very clear. The differences in size and cost are also great. Earmax was intended as a portable tube amplifier!
Michael was worried about the Grado RS-1 with Earmax Silver. I tend to agree that RS-1 sounds best out of a portable. Because it sounds good there (also compared to many other headphones) I also imagined that it had a potential to sound magnificent with the right amp. I have to say that I had to give up here, the RS-1 doesn't scale well and doesn't improve much by better amplification. HD650 is quite different here, it sounds boring and lifeless with bad amplification and improves to a very high level of reproduction with a good amp and source. So, at least for my taste, the RS-1 is the problem. IMO, IMHO etc. But I know some Head-Fiers like Grado and with Earmax Pro or Silver. Maybe some other output tubes will match better.
I mostly used my Earmax with HD650 and K701 and I think they have good synergy with the amp. Tuberolling can really help because it is difficult to find tubes that fit both headphones equally well. I tried it shortly with my HD800 and there I felt that the Earmax is not the amp to go for, it did not sound bad in any way but did not keep up to the potential of the headphone.
The main difference between the Silver and the Pro is that Silver has more power and also is more suited to low impedance headphones. HD650 works well with both headphones but Silver has a little more power and control. K701 is very sloppy in the bass with Pro but sound great with Silver. As I understand it, Earmax Silver is close in construction to Earmax Anniversary (discontinued since many years) except that Anniversary was delivered with selected NOS tubes.
