Back in the October 2002 issue we noted that we intended to
produce a replacement module for the very popular ETI-480 amplifier
module which was published back in December 1976 - 26 years ago.
In the same note we stated, somewhat controversially, that the
ETI-480 was a dog of an amplifier and that it was not a good
performer, even by 1976 standards.
Having made that outrageous statement (to some readers, at
least), we had to come up with the goods. Fortunately, we were
pretty confident that we could, and we are pleased to state that
this new module is even better than we had hoped.
It uses the same power output transistors as in the ETI-480 and
just one more low-cost transistor has been added to the overall
component count. Kit cost should be about the same as for the
ETI-480.
But the SC480 is as modern as tomorrow -
with performance to match.
The transmogrification of an amplifier. Many
readers will recognise the venerable (26-year-old!)
ETI-480.
Performance
Output Power |
50 watts into 8Ω 70 watts into 4Ω |
Music Power |
77 watts into 8Ω ;105 watts into 4Ω |
Frequency response |
-1dB at 14Hz and 70kHz (at 1W- see Fig.1) |
Input sensitivity |
0.875V for 50Ω into 8Ω |
Harmonic distortion |
<.05% from 20Hz to 20kHz; typically
<.003% |
Signal-to-Noise Ratio |
-114dB unweighted (22Hz to 22kHz); -119dB
A-weighted, both with respect to 50W into 8Ω |
Damping factor |
>140dB at 100Hz & 1kHz, with respect to 8Ω
and without PTC thermistor |
Protection |
fuses plus "Polyswitch" PTC thermistor |
Stability |
unconditional | |