Summit Audio FEQ-50 User manual

Summit Audio Model FeQ-50
Four-Band Parametric Passive Equalizer
Summit Audio, Inc.
P.O. Box 326
Gardnerville, NV 89410
[phone]
email: [email protected]
Operation Manual

Model FeQ-50 4-Band Passive, Parametric Equalizer
2
Introduction
Introducing the FeQ-50 four band parametric, passive
equalizer from Summit Audio. The focus of the FeQ-50 from
the very beginning has been the sound. Passive circuitry
excels at rich harmonic content and phase coherency,
resulting in a musically satisfying sonic experience.
Each of the four bands has six switch selectable frequencies
and 14dB of fully sweepable cut or boost. The low and high
bands can switch between peaking and shelving filters, the low
mid and high mid can switch between narrow and wide band-
widths. Also included is a switchable highpass filter fixed at
30Hz with a gentle 6dB/octave rolloff to reduce rumble. I/O
includes a total of four simultaneous outputs, -10dB and +4dB
vacuum tube out and –10dB and +4dB solid state out. Like all
of our other half-rack sized products, the FeQ-50 has an
internal power supply and 3 year warranty.
DANGER!
HIGH VOLTAGE
IMPORTANT: Check
the bottom sticker
to make sure the
FeQ-50 is manufac-
ture for the voltage
used in your country.
This is done at the
factory or by a
qualified service
center only.

Model FeQ-50 4-Band Passive, Parametric Equalizer
3
Introduction
Features
• Fully passive design (no amplifier in filter circuit)
• Four frequency bands
• ±14dB cut and boost
• Six switch selectable frequencies per band
• Separate, bypassable high pass filter
• Master bypass
• Four simultaneous outputs, both vacuum tube and solid
state
• Internal high voltage power supply
• One 12AX7A/ECC83 vacuum tube
• 3 year warranty
• Hand Crafted in the U.S.A.
Carefully unpack the FeQ-50 and it’s power cord. Save the
carton and packing material for possible future use. Before
powering up the unit, read this manual and observe the
cautions for HIGH VOLTAGE .
Important Warranty Information
For your 3 year warranty, register your FeQ-50 on line today
at www.summitaudio.com .

Front Panel
4
Summit Audio, Inc.
Front Panel
Low Band
The Low EQ band can be set for either a peak or shelving
response and can boost or cut by up to ±14dB. The center
point of the filter band can be set to any of six frequencies:
33Hz, 60Hz, 100Hz, 150Hz, 270Hz, or 410 Hz.
Low-Mid Band
The Boost/Cut controls can boost or attentuate the chosen
frequencies by up to ±14dB.
The Bandwidth (Q) is slightly less than 2 octaves in the
narrow setting and slightly more than 3 octaves in the wide
setting (maximum gain).
The center point of the filter band can be set to any of six
frequencies: 390hz, 470Hz, 560Hz, 680Hz, 820Hz, or
1kHz.
Hz Hz kHz kHz
Passive EQ
270
150
100
60
33
0
+14-14 +14-14 +14-14 +14-14
000
410 680
560
470
820
1K
390
3.3
4.75.6
2.2
1.5 7.28.2 10 12.5
18
IN
ON POWER
BYPASS
5
1.2
FeQ-50
OFF
HPF
Hz
270
150
100
60
33
0
+14-14
410
Boost/Cut
Freq.
Select
Peak/Shelf
Boost/Cut
Bandwidth
Freq.
Select
+14-14
0
Hz
680
560
470
820
1K
390

Model FeQ-50 4-Band Passive, Parametric Equalizer
5
Front Panel
High-Mid Band
The Boost/Cut controls can boost or attenuate the chosen
frequencies by up to ±14dB.
The Bandwidth (Q) is slightly less than 2 octaves in the
narrow setting and slightly more than 3 octaves in the wide
setting (maximum gain).
The center point of the filter band can be set to any of six
frequencies: 1.2 kHz, 1.5 kHz, 2.2 kHz, 3.3 kHz, 4.7 kHz
and 5.6 kHz.
High Band
The High-Mid EQ band can be set for either a peak or
shelving response and can boost or cut by up to ±14dB. The
center point of the filter band can be set to any of six
frequencies: 5 kHz, 7.2 kHz, 8.2 kHz, 10 kHz,
12.5 kHz, or 18kHz.
Bandwidth Control
On the two mid-bands, the bandwidth control sets the Q or
width of the bell-shaped response curve. The bandwidth
circuit employs a “proportional Q” design, which results in a
wider bandwidth at low boost/cut settings and a narrow
bandwidth at high boost/cut settings.
Peak or Shelving Response
The Low and High EQ bands can be set for either peak or
shelving response. In shelf mode, for example, the High band
continues to boost or cut frequencies above the center
frequency. In peak mode the High band creates a bell-shaped
response curve.
Boost/Cut
Bandwidth
Freq.
Select
+14-14
0
kHz
3.3
4.75.6
2.2
1.5
1.2
Boost/Cut
Peak/Shel
f
Freq.
Select
kHz
+14-14
0
7.28.2 10 12.5
18
5

Front Panel
6
Summit Audio, Inc.
High Pass Filter
To reduce rumble or sub-audio frequencies, you have the
option to enable this virtually transparent highpass filter. The
frequency is fixed at 30Hz with a gentle 6dB/octave relief.
Bypass Switch
This switch bypasses all the passive EQ sections, but NOT
the tube output stage which allows you to use the FeQ as a
tube enhancement device to add warmth and natural sound
to your digital recordings even when you don’t need the EQ.
The FeQ-50 can also be used to convert -10dB (consumer)
level signals into +4dB (professional) level.
Important - Please Read!
The FeQ-50 contains a vacuum tube which
generates heat.
Do not block the cooling holes on the top of the
FeQ-50 and always allow adequate ventilation when
mounting the unit in a rack enclosure.

Model FeQ-50 4-Band Passive, Parametric Equalizer
7
Rear Panel
Rear Panel
A.C. Receptacle
The FeQ-50 is factory wired for either 100, 115 or 230
Volts AC. Before connecting AC power make sure the FeQ is
wired for the voltage used in your country.
XLR Line Level / 1/4” Line Level Input
The Neutrik combination jack accepts either a balanced XLR
or balanced 1/4” phone plug. The balanced XLR input is
designed for +4dB line level input signals. The 1/4” input is
designed to accept -10dB input levels only.
Note: You can use all
four tube and solid
state outputs at the
same time for added
versatility.
XLR Balanced Tube Output
This is a +4 dB balanced, low impedance XLR output connec-
tion compatible with professional recording and audio equip-
ment. The tube output provides a warm, natural tube sound.
-10 BAL. +4 BAL. -10 UNBAL +4 BAL.
TUBE
MODEL FEQ-50 20W MAX
SUMMITAUDIO.COM -10 BAL.+4 BAL.
SOLID STATE PUSH
FUSE
115V USE 250-MA FUSE 220V USE 125MA FUSE

Basic Operation
8
Summit Audio, Inc.
1/4” TRS Balanced Tube Output
This is a -10dB, balanced 1/4” output designed to interface
with your recording device, compressor or EQ.
XLR Balanced Solid State Output
This is a +4dB, balanced, low impedance output connection
compatible with professional recording and audio equipment.
The Solid-State output provides a clean, low-noise signal.
1/4” TRS Balanced Solid State Output
This is a -10dB, balanced 1/4” output designed to interface
with your recording device, compressor or EQ.
Basic Operation
Setting up a Parametric EQ
1. Turn up the gain on the band you are working with. This allows
you to easily hear the effect of the filter.
2. Switch in the Narrow ( ) bandwidth setting.
3. Adjust the Center Frequency to “zero-in” on the frequencies
you wish to boost or cut.
4. Now that you’ve found the frequency you want, set the Gain to
a more conservative value.
5. Widen the Bandwidth, if desired, to create a more natural
sound.
6. Adjust the other bands as needed.
Important: For
proper operation of
the FeQ-50 (or any
vacuum tube device
for that matter),
allow the unit to
warm up with power
on for 15 minutes
before use.
Important: Do not
block the cooling
holes and allow
adequate ventilation.

Model FeQ-50 4-Band Passive, Parametric Equalizer
9
Applications
Applications
Dual-Output Mic/EQ Channel
The FeQ-50 in conjunction with the Summit Audio 2BA-221
provides you with a world-class mic preamp and passive EQ
channel. As a bonus, you can record both the tube and solid-
state outputs of the FeQ-50 on separate tracks.
-10 BAL. INSERT
SUMMIT AUDIO INC. CARMEL, CA USA
MIC
FUSE +4 BAL.
SUMMITAUDIO.COM
MODEL 2BA-221 20W MAX
OUTPUTS
OUT
IN IN
STACK
INPUTS
2BA-221
+4 Output
Mic. Input
Tube
Out
Solid-State
Out
Microphone
FeQ-50
-10 BAL. +4 BAL. -10 UNBAL +4 BAL.
TUBE
MODEL FEQ-50 20W MAX
SUMMITAUDIO.COM -10 BAL.+4 BAL.
SOLID STATE PUSH
FUSE
115V USE 250-MA FUSE 220V USE 125MA FUSE
To
Recording Device
or Line Mixer
To
Monitor System
Microphone Channel

Applications
10
Summit Audio, Inc.
Mixer Insert
The Summit Audio FeQ-50 can be used to add world-class EQ
to virtually any mixing board. The FeQ-50 should normally be
interfaced using the insert point on your mixing board.
Most mixing boards contain a TRS (tip-ring-sleeve) insert
point. A special TRS insert cable, as diagrammed below,
makes this patch quick and easy.
Note: Check the Insert level on your mixer. If your mixer uses
a 0db to +4dB insert point, use the +4dB input and output
on the FeQ-50 and an insert cable with XLR connectors.
To TipTo Ring
Channel
Insert
Mixer
Signal Out of Mixer
Signal Return to Mixer
Tip Ring
FeQ-50 Input FeQ-50 Output
INSERT CABLE
Signal is sent out on tip of plug and
returned to mixer via ring of plug.
-10 BAL. +4 BAL. -10 UNBAL +4 BAL.
TUBE
MODEL FEQ-50 20W MAX
SUMMITAUDIO.COM -10 BAL.+4 BAL.
SOLID STATE PUSH
FUSE
115V USE 250-MA FUSE 220V USE 125MA FUSE
Hz Hz kHz kHz
Passive EQ
270
150
100
60
33
0
+14-14 +14-14 +14-14 +14-14
000
410 680
560
470
820
1K
390
3.3
4.75.6
2.2
1.5 7.28.2 10 12.5
18
IN
ON POWER
BYPASS
5
1.2
FeQ-50
OFF
HPF
Mixer Insert

Model FeQ-50 4-Band Passive, Parametric Equalizer
11
Applications
Instrument Input Channel
For a great bass or guitar sound, add the Summit Audio
TD-100 instrument preamp and tube direct box in conjunc-
tion with the FeQ-50.
Plug your instrument into the front panel of the TD-100 and
run a balanced 1/4" cable from the output of the TD-100 to
the input of the FeQ-50. Connect the 1/4” output of the
TD-100 into the FeQ-50’s input. Connect the 1/4” output of
the FeQ-50 (either tube or solid-state) to the line in on your
amp.
+4 Balanced
cable
Instrument Preamp & Passive EQ

Applications
12
Summit Audio, Inc.
Ultimate Stereo Stage Setup
You can have the best of the tube and solid-state worlds with
this stereo stage setup. Although two amps are needed, the
two outputs of the FeQ-50 each impart a distinctive sonic
signature which works beautifully to help provide the illusion
of two players. The sound-sculpting possibilities are vast!
The Summit Audio TD-100 instrument preamp and tube
direct box provides a line level signal for the FeQ-50. The
balanced tube output of the FeQ-50 feeds a digital delay
which drives the right side amplifier. The solid state output of
the FeQ-50 goes directly to the left side amplifier.
Line input
Digital Delay Unit
Amp
Stage Left
Amp
Stage Right
Solid-State
Out
+4 Balanced
Output
Input
Low-level
Output
Input
Input
Tube Out
Stereo Stage Rig

Model FeQ-50 4-Band Passive, Parametric Equalizer
13
Block Diagram
Block Diagram
The electronically balanced input stage input goes directly
into the passive EQ sections. The low and high bands can
switch between peaking and shelving filters, the low mid and
high mid can switch between narrow and wide bandwidths.
Also included is a switchable highpass filter fixed at 30Hz
with a gentle 6dB/octave rolloff to reduce rumble. I/O
includes a total of four simultaneous outputs, -10dB and
+4dB vacuum tube out and –10dB and +4dB solid state out.
BYPASS
BYPASS
SHELF PEAK
BOOST/CUT BOOST/CUT BOOST/CUT BOOST/CUT
DIFFERENTIAL
INPUT
TUBE
DIFFERENTIAL
OUTPUT
SOLID-STATE
DIFFERENTIAL
OUTPUT
+
-
+
-
IN
IN
WIDE NARROW WIDE NARROW SHELF PEAK
HIGH PASS
LOW
FILTERS
LOW-MID
FILTERS
HIGH-MID
FILTERS
HIGH
FILTERS

Electrical Connections
14
Summit Audio, Inc.
Electrical
Connections
Input
(Combination XLR line level / 1/4” line level jack)
Balanced 3-pin XLR
(+4dB)
Pin 1 - - Ground
Pin 2 - - (+) Signal
Pin 3 - - (-) Signal
Balanced 1/4” Jack (-10dB)
Sleeve - Ground
Tip - - - - (+) Signal
Ring - - - (-) Signal
Solid State and Tube Outputs
Balanced 1/4” jack Balanced 3-pin XLR
(-10dB) (+4dB)
Sleeve- - Ground Pin 1 - - Ground
Tip - - - - (+) Signal Pin 2 - - (+) Signal
Ring - - - (-) Signal Pin 3 - - (-) Signal

Model FeQ-50 4-Band Passive, Parametric Equalizer 15
Specifications
Specifications
Circuit Topology
Tube Output: High-voltage Class A
Solid-State Output: Class A/B
Power
Internal AC Supply
15 watts
115 volts
50 or 60 Hz
Fuse size is .5 amp, slo-blo for 100/115 V
Fuse size is .25 amp, slo-blo at 230 V
Dimensions
W: 8.5”, H: 1.75”, D: 8.5”
(Two units fit side by side on a standard one-space rack
shelf. Order the SRK-100 Rack Kit from Summit Audio.)
Weight
7 pounds (3.15 kg)
Audio Specs
For current audio specifications please contact
Summit Audio at www.summitaudio.com.

Summit Audio, Inc.
P.O. Box 326
Gardnerville, NV 89410
web page: www.summitaudio.com
email: [email protected]
Please register on-line today at www.summitaudio.com.
Thanks.
Doc# 1094A00 ©2005 Summit Audio Inc. All Rights Reserved