D I O... P A P E R
The secret behind the Zen Triode output transformers is that they are patterned
after the older Peerless iron that was hand-scramble-wound for ultra wide
bandwidth and flat response. If you are familiar with the any of the all time
great vintage tube amps you already know the Peerless output
transformers were a large factor.
Our transformers are also
hand scramble wound using a winding topology that evolved from several prototypes. The air-gapped
made from top grade USA made grain- oriented-silicon-steel - the heart of
any transformer. The better the core the less of it you need and the lower
the saturation. In contrast transformers made in China do not have the
same quality steel and suffer as a result.
Add to that the fact that I choose to locate them on a
different plane than the power transformer and at the opposite end of the amp
where no field is present. Instead of using end-bells the chassis is
used to shield it.
I also choose a single 6 ohm tap because I found
the single tap prototypes sounded better than the multi-taps, something about
the unused taps. The primary impedance is 9800 ohms with 2850 winds. This
makes the el84 and SV83 tubes couple more power as the speaker impedance drops.
Max power is at 2 ohms.
If you measure the current and voltage on
an SE84C Zen Triode Amp with a
1KHZ sign at 2 volts you will find the current output actually exceeds the
Many people think transformers have to be huge to be good, but
its all in the quality of the steel.
rather unique feature of our output transformers is that they
float. They have no reference to ground. This is
difficult to do in all but the most stable amplifier circuits.
Now there is a big fuss
is over COBALT transformers
There is no evidence that "cobalt" transformer
will sound better than our transformers in a Zen Triode Amp. What it has going for it is a catchy
name, high cost, low availability, and it's the hot topic over in
Magnaquest/Bottlehead land. I'm sure it's good, as is nickel, but after reading
all the chit chat about it on the Internet I recognize that it's being largely
overblown. The majority if not all are done without air-gaps necessitating a
parafeed design. We went through all that three years ago and concluded that
parafeed does not sound better to our ears. It does however perform better
which brings us down to the brass tacks of building amps that excel in
performance (ie. parafeed, constant current, etc.) or simpler "zen" like designs
that to our ears sound better (but perform worse). Take your
The main advantages that nickel has over steel is less
saturation. There are two ways to deal with saturation. A) use nickel or
"cobalt", or B) just size the damn things 3 times bigger than they need to be so
they don't saturate. Our transformers do not saturate until somewhere between
15 and 20 watts. Now depending on the amp we build, that is between 3 and 10
times oversized. You can be sure that if someone is using expensive core materials like
nickel or cobalt they aren't likely to oversize the transformers.
will point out that transformers in general induce distortions
and therefore not using one is better than using one. Output
transformerless amps (tube) are often great sounding amplifiers,
however they are also finicky about speakers and have many other
disadvantages. We feel the transformer is a major key
to why most people think tube amps sound better than solid state.
The transformer couples the output stage to the hostile
impedance of the loudspeaker in a synergetic way not possible
way of doing things in the high power high-end audio world is
to build high power amplifiers with high dampening ratios so
that they will better control the speaker and be less effected
by the feedback voltage generated by it. On the other
end are speakers with high power ratings, low efficiency and
complex crossovers that attempt to show the amp a less hostile
impedance curve. Basically put, amps that are less effected
by (can't feel) the speakers, and speakers that are less effected
by (can't feel) the amps.
In a great
high fidelity tube system the output transformer makes the speaker
aware of the amp, and the amp aware of the speaker. The
two work together, reacting to each other with any given passage
of music. This is call synergy. It is made possible
by output transformers. The best vintage solid state amps
I've heard from the 60's and 70's used output transformers.
transformers are not a bad thing.
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2007 2008 by Steve Deckert