Chapter 4:Waxing Philosophical
4.1 When to EQ?
UT Twin87
Twin-Circuit Condensor Microphone
11
Owner’s Manual
Version 1.0 as of 11/15/2021
Additional Support
Visit www.unitedstudiotech.com for additional
support.
UT Twin87
Twin-Circuit Condensor Microphone
10
Owner’s Manual
Version 1.0 as of 11/15/2021
Additional Support
Visit www.unitedstudiotech.com for additional
support.
Chapter 2: About the UT Twin87
2.1 Recreating Two Classics
Chapter 2: A Bit of History
2.1 In the beginning...
The updated ‘Modern’ version of this
design was introduced in 1986, and
featured many design updates which
were simply not practical to imple-
ment in the original version. One
such update was the inclusion of an
RF filter to help the mic perform in
-
side of broadcast facilities or in loca-
tions with a high amount of RF activ-
ity. Another feature added was the
inclusion of a voltage boost circuit to
provide a constant and higher polar-
ization voltage to the capsule, mak-
ing up for any shortcomings caused
by direct polarization from phantom
power. A ‘golden reference’ speci-
men of this design was also studied
as a basis for the UT Twin87, when set
to Modern mode.
Both the vintage and later editions
of this microphone have become a
modern classic and a go-to for cre-
ating clear, articulate, punchy vocal
tracks that cut through a mix, across
many different styles of music.
The circuit design of the UT Twin87
is no gimmick or mere emulation of
the attributes of a classic microphone
- it is a faithful and meticulous rec-
reation of two distinct circuit paths,
which took several years of research
and prototyping to get just right. We
meticulously analyzed both circuits,
teasing out the subtle differences
between the two. Those differenc-
es were subtle; yet real and quan-
tifiable. They mainly related to the
two different methods and voltage
levels by which the capsule was po-
larized, as well as subtle differences
in component values and tolerances
within the de-emphasis and High-Z
sections. We implemented both of
these distinct layouts faithfully, onto
their own boards, and selectable by
switch. From there, we follow that se-
lection with a faithful reproduction of
the amplifier section from the classic
design, followed by an output trans-
former section of our own design, but
inspired by the larger incarnations
of the ‘87 output transformer. We
developed our output transformer
specifically to be large enough and
wound in such a way as to provide a
silky output without any real restric-
tion of the low end or dynamic range.
There has definitely been much dis
-
cussion over the RF filter utilized in
the later ‘AI’ versions of the classic cir-
cuit. While the need to have such a
filter in high-RF environments is not
disputed, some have claimed that
the mic will sound more open and
natural without this filter, all oth
-
er things being equal. Others have
claimed that the difference is in-
audible. We do agree that if you do
not NEED the filter engaged, then it
is probably best to go through the
least amount of circuitry;, hence the
RF filter on the UT Twin87 ships from
the factory in the ‘off’ position. We
wanted to do more than provide this
filter if you need it; however, we also
wanted to make it sound good. We
ever so slightly played with the filter
curves and used much nicer compo-
nents than are often found on such
filters (WIMA audio grade film caps
and wirewound inductors opposed
to cheaper ceramic caps and more
generic components), so that this fil
-
ter, when engaged, would, with luck,
provide a sweetening effect rather
than be detrimental. We believe we
have accomplished this, and the fil
-
ter, when engaged, will provide just
the ever slightest top end emphasis
and sweetening, while putting subtle
‘bookends’ around the audible fre-
quency range. Keep in mind that this
filter technically operates FAR outside
of human hearing, and thus its ‘sec-
ondary effects’ on the sound you do
here are going to be extraordinarily
subtle. In the end though, this still
makes for a very interesting sonic ex-
periment.
2.2
GETTING THOSE SUBTLE DIFFERENCES RIGHT!
2.3
TO FILTER OR NOT TO FILTER…
1967.
Solid-state transistors are
changing the world with
their reliability, portable de-
sign, heat dispertion, power
requirements, and cost. Initially designed as a solid state replace
-
ment for yet another discontinued tube model; the classic FET
microphone became a classic unto itself and has remained a work
-
horse of commercial studios since its release. Known for its cutting
edge, focused sound and tight voicing; it became a new standard
for lead vocal capture. In a new era of electrified instrumentation,
it became known as a “must-have” microphone that was used on
countless recordings. It’s popularilty lead to a production that ran
from 1967 to 1986.
Most highly regarded were specimens of this mi-
crophone produced in the first production runs, in the late 1960’s.
It was a ‘golden reference’ unit from this vintage that served as the
basis for the UT Twin87 design, when set to Vintage mode.
CHAPTER 2:
ABOUT THE UT TWIN87
2.1
RECREATING TWO CLASSICS
U
T
Twi
n
87