User Manual

8
[ Fig.17 ] Output signal of an amplifier, “Competitor A”. (2500W @ 2ohms)
The oscilloscope measurement on Fig. 17 shows strong
compression-like behavior on its output signal. The
output signal shows no resemblance of the input sine
wave. This behavior was not seen when the amplifier
was driven only on one channel, but quickly became
unstable when driven on both channels. We believe this
to be result of overstressing of the one power supply that
supplies power for both channels.
[ Fig.18 ] An oscilloscope measurement of amplifier model “Competitor B”.
(2900w @ 2 ohms)
Fig.18 shows that Competitor B, rated 400 watts higher
than the T5n at two ohms, seems to start out well but
quickly loses power and its output voltage drops. This
behavior was observed when the amplifier was driven
on both channels.
[ Fig.19 ] “Competitor C” - Rated at 3300W into two ohms, this amplifier
muted quickly after its limiter kicked in. (3300W@ 2 ohms)
Fig.19 shows the output signal of amplifier model,
“Competitor C”. Though this amplifier is rated at
3300W into two ohms and specified to have the highest
power of all the amplifiers in this comparison, the
oscilloscope trace shows contradicting results. Its limiter
kicked in, drastically dropping output voltage. Though
not apparent on one still image of the measurement, it
took a few seconds for the output voltage to recover,
only to have the limiter activated once again shortly
afterwards. This behavior repeated for the entire
duration of this test.
These results show that different amplifiers behave
differently under low impedance operation. The results
of the comparison also prove that actual performance of
an amplifier cannot always be predicted from its catalog
specifications. Because there are no industry standards
for amplifier specifications, paper comparison of figures
such as output power is not very practical.
3.3. Explanation of results of listening test
using music source
We conducted the above experiment using a music
source. To replicate a more realistic setup, we replaced
the dummy load on one channel with four loudspeakers
connected in parallel. To reduce interference between
the four loudspeakers and also to reduce stress on our
ears, we verified our results from one reference
loudspeaker; the remaining three loudspeakers were
placed in a remote location.
The results of this listening test were basically