OWNERS MANUAL for Model SE84UFO3 PAGE 15
The Zen Triode Amplifier, model SE84UFO3 is the mono incarna?on of
the 2 waI stereo amplifier that started Decware in 1996. This amp
design set the benchmark extremely high and with 20 years of
improvements it con?nues to haunt even the best sounding high
dollar amplifiers made today.
The design is based on geing an audio circuit as simple as possible
with respect to parts count and lay it out in such a way that eliminates
circuit boards and as much connec?ng wire as possible. In this spirit
an amplifier circuit consis?ng of only 1 capacitor and 2 resistors in the
signal path was laid out in such a way that primarily only parts leads
are used to connect to each other reducing the solder nodes
drama?cally. The en?re tube amp is actually far simpler than even a
single op-amp.
To maximize the poten?al transparency of this approach, proprietary
wide bandwidth interleaved air-gapped single ended transformers are
used to ensure no transparency is lost in the output transformer itself.
Addi?onally, a triode circuit is used which is linear under a wide range
of speaker loads so that it requires no fidelity robbing nega?ve
feedback.
To ensure 2 waIs can drive difficult speaker loads the primary
impedance ra?o for the output stage is much higher than normal so
that when a speaker’s impedance starts to dip down, the point where
many tube amps loose ground, the reflected impedance to the output
tube plates also drop puing it more into the tubes happy zone
crea?ng a condi?on where the amp puts out more power instead of
less.
The result of this thinking is that the amp can drive virtually any
loudspeaker load with a good frequency balance and ?ght bass
response. This even includes magne?c panel speakers and
electrosta?c loudspeakers. The only considera?on with the amplifier
is how loud it will play with the given efficiency of your loudspeakers.
Ideal loudspeakers for this amp are speakers rated in the mid to high
90’s. Example, 94dB 1w/1m works well in even larger spaces.
(con?nued on next page)
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Design Notes
