This was an interesting article! I'm always curious about how the Berning designs compare with mainstream OTLs.
However, I've found that in testing components, often the devil is in the details. So much so, that the shootout might not be as conclusive as it seems.
In the shootout, was the Berning kept far away from any steel or iron objects, such as other components? Was it sitting on a steel shelf, or near a steel frame of a component stand?
I have the ZH-270. I have noticed--and Dave Berning has confirmed--that it is sensitive to nearby magnetic objects. This is why the case is made of aluminum.
You can try an experiment: wave a steel bookend or something like it over the amp and notice how the sound closes down! (This is true for many components, but perhaps the ZH-270 is especially sensitive because it has so little iron and steel in it to begin with.) You will get the best sound if you keep the amp well away from any steel.
Also, I have found that the sound changes depending on where you place the amp. On the floor, between two large floorstanding speakers, it didn't have the same tight bass control that it does when on a heavy wood table near a supporting wall; frankly, it was a bit boomy. Placed on the table, the boom went away! Further, although it sounds fine on its ordinary rubber feet, placing it on carbon fiber cones seems to change the sound, making the midrange clearer, I think, although this is something of a matter of taste perhaps.
I've tried a couple different power cords...they don't seem to make that much difference, although it is noticable. Interconnects and speaker cables had *much* stronger influence on the sound. Sometimes, I wonder if the cables make more of a difference that the amp; the changes are that large. (I'm comparing $300 vs. $500 silver interconnects. Not the most esoteric wires, but both well-regarded.)
Were the differences between the Tenor and the Berning something which could be accounted for by differences in their interaction with the cables used? Did you check if different cables changed the results? One cable might suit the Tenor better than the Berning. It's at least conceivable since the differences I've heard among cables are significant.
Did you use a preamp in the test? By virtue of it's most ingenious feature--a volume control and A/B switch--the Berning can dispense with a pre-amp and and extra pair of interconnects. Now, this may be "cheating" in a test against another amp which requires a preamp, but if you only need two inputs, the Berning let's you go direct, which can only improve matters. And save significant $. Was this advantage realized in the shootout?
Although Berning's power supply is rated to work with as little as 100V, I've noticed that at that level, power is significantly reduced, and sound suffers even playing at moderate levels. (I live in Japan, where 100V mains is standard, so I use a step-up transformer.) Run with 115V, the sound is much more dynamic and natural. Are you sure that mains voltage was to spec when you ran your shootout? It is not uncommon for it to sag during the day.
However, I've found that in testing components, often the devil is in the details. So much so, that the shootout might not be as conclusive as it seems.
In the shootout, was the Berning kept far away from any steel or iron objects, such as other components? Was it sitting on a steel shelf, or near a steel frame of a component stand?
I have the ZH-270. I have noticed--and Dave Berning has confirmed--that it is sensitive to nearby magnetic objects. This is why the case is made of aluminum.
You can try an experiment: wave a steel bookend or something like it over the amp and notice how the sound closes down! (This is true for many components, but perhaps the ZH-270 is especially sensitive because it has so little iron and steel in it to begin with.) You will get the best sound if you keep the amp well away from any steel.
Also, I have found that the sound changes depending on where you place the amp. On the floor, between two large floorstanding speakers, it didn't have the same tight bass control that it does when on a heavy wood table near a supporting wall; frankly, it was a bit boomy. Placed on the table, the boom went away! Further, although it sounds fine on its ordinary rubber feet, placing it on carbon fiber cones seems to change the sound, making the midrange clearer, I think, although this is something of a matter of taste perhaps.
I've tried a couple different power cords...they don't seem to make that much difference, although it is noticable. Interconnects and speaker cables had *much* stronger influence on the sound. Sometimes, I wonder if the cables make more of a difference that the amp; the changes are that large. (I'm comparing $300 vs. $500 silver interconnects. Not the most esoteric wires, but both well-regarded.)
Were the differences between the Tenor and the Berning something which could be accounted for by differences in their interaction with the cables used? Did you check if different cables changed the results? One cable might suit the Tenor better than the Berning. It's at least conceivable since the differences I've heard among cables are significant.
Did you use a preamp in the test? By virtue of it's most ingenious feature--a volume control and A/B switch--the Berning can dispense with a pre-amp and and extra pair of interconnects. Now, this may be "cheating" in a test against another amp which requires a preamp, but if you only need two inputs, the Berning let's you go direct, which can only improve matters. And save significant $. Was this advantage realized in the shootout?
Although Berning's power supply is rated to work with as little as 100V, I've noticed that at that level, power is significantly reduced, and sound suffers even playing at moderate levels. (I live in Japan, where 100V mains is standard, so I use a step-up transformer.) Run with 115V, the sound is much more dynamic and natural. Are you sure that mains voltage was to spec when you ran your shootout? It is not uncommon for it to sag during the day.