I have heard the Elekit 300b and I think it is a very nice sounding amp, particularly for the money. I have not heard any of the speakers you are considering with that amp, or for that matter, any other single-ended 300b amp.
Heresy and the Zu are quite different sounding speakers. I find the Zu speakers to be very dynamic an exciting, but they are also somewhat lean in the upper bass region, and somewhat hard and brittle sounding (excessively "crisp"). It is tempting to think that the Elekit is the exact opposite so that they may complement each other, but, that is not often the case--usually speakers of a certain sound actually go better with amplifiers of the same kind of sound.
I like the sound of the Heresy, Forte and Cornwall and I suspect they are a safer recommendation than the Zu. They do have some of the tonal colorations common to most horn-type systems (peak in the upper midrange, a tendency to "shout" at higher volume levels, somewhat weak in very deep bass), but, horn systems that ameliorate these issues better are typically MUCH more expensive.
High efficiency speakers that go well with a single-ended 300b amp tend to be somewhat pricey, so you might consider looking for something used.
Heresy and the Zu are quite different sounding speakers. I find the Zu speakers to be very dynamic an exciting, but they are also somewhat lean in the upper bass region, and somewhat hard and brittle sounding (excessively "crisp"). It is tempting to think that the Elekit is the exact opposite so that they may complement each other, but, that is not often the case--usually speakers of a certain sound actually go better with amplifiers of the same kind of sound.
I like the sound of the Heresy, Forte and Cornwall and I suspect they are a safer recommendation than the Zu. They do have some of the tonal colorations common to most horn-type systems (peak in the upper midrange, a tendency to "shout" at higher volume levels, somewhat weak in very deep bass), but, horn systems that ameliorate these issues better are typically MUCH more expensive.
High efficiency speakers that go well with a single-ended 300b amp tend to be somewhat pricey, so you might consider looking for something used.