The Zen
High Fidelity Engineering Co.
www.decware.com
DESIGNER'S NOTES
:
Steve Deckert, High Fidelity Engineering Co.
While we've been enjoying the success of
our our Zen Triode amplifiers this past 4
years, I have personally talked to every cus-
tomer (over 1000) before and after his or
her purchase of an amplifier. This feedback
about how our products are received in the
real world (vs. a lab bench and reference lis-
tening room) has brought about tremendous
insights as to what works well and what
doesn't. Before, during and ever continuing
are a whole family of secret Zen amps that
no one knows about - an ongoing experi-
ment that results in prototype after proto-
type.
In these prototypes, as mentioned in the
previous page, there are several different
tubes. Sticking to just the popular triodes,
we have found that we can make some very
impressive sounding amplifiers with them.
We have learned that the signatures com-
monly associated with particular tubes are
predominately effected by the design of the
amplifiers using them... point being that
stereotypes where tubes and or tube amps
are concerned can be misleading.
During these cycles of R&D that we go
through, we're not afraid to experiment with
off the wall tubes because we frankly don't
care about anything other than the final re-
sult, the sound of the amp.
Our very first amplifier was the original Zen
Triode Amp that used the EL84/6BQ5 output
tubes. These are pentodes that can be wired
in triode. The SV83 tubes is a special version
of this made for Video applications such as
Radar Displays in the Russian Military. Be-
cause it was a video tube it had some special
qualities not found in the EL84/6BQ5 tubes
that we were simply not too blind to recog-
nize. Sventlana, who makes the tube, con-
tacted all the major tube amp manufactures
suggesting it might be a special sounding
tube to base an amplifier design around. Not
one of them listened.
The appeal in designing around these small
envelope tubes comes from years of listen-
ing to them in a wide variety of amplifiers
throughout the 60's and 70's. I recognized
these tubes had speed that many larger
tubes did not, and I always enjoyed them.
Of the larger envelope tubes, the big brother
of the EL84/6BQ5 was the EL34. It has the
narrowest envelope of any output tube, and
was used in just as much gear in that time
period. Like the smaller one, I noticed it too
always seemed to have better speed, and
tighter bottom end than the larger valves.
The EL34 also has a unique feature in that it
is the only pentode made that can be wired
in true triode for lack of internal jumpers be-
tween the grids. This gives you limitless pos-
sibilities for how you combine the grids and
plate to accomplish triode operation. With
exhaustive research I have found that it is in
this key part of the tube that you can control
the depth and dimensionally of the resulting
soundstage.
In true triode it sounds like other triodes,
with an immediacy and presence triodes are
famous for. In Zen triode (get it), holo-
graphic imaging and huge soundstage along
with more attention to harmonics can be ex-
tracted. The EL34 makes it possible to take
this a level deeper which I feel I've been
able to do.
In audio it's hard to pay Peter with our rob-
bing Paul. Everything is a tradeoff it seems,
and it's hard to have both. There are things
that I really like about the pure triodes, and
being a soundstage fanatic, there are things
that I really like about pentodes wired in tri-
ode, especially EL34's. So to have both, I
designed an amp that has both.
