I don't know if it's a marketing gimmick or not, but as good as the 401HR is, the 401au is better IMO.
I have heard the 401HR in comparison to the Butler 2250 and to me it's a toss up. They both are very nice amps. I think the Moscode has a slight edge in tonal balance and overall presentation, especially sound staging and high end frequency reproduction. However, if you need a little extra power the Butler might be the better choice.
I have heard the 401HR in comparison to the Butler 2250 and to me it's a toss up. They both are very nice amps. I think the Moscode has a slight edge in tonal balance and overall presentation, especially sound staging and high end frequency reproduction. However, if you need a little extra power the Butler might be the better choice.