UDO AUDIO Da Capo 75 User manual

.
... just pure and real
udo roesner amps
cook book
acoustics
roesner
udo 7
5

7
5
udo roesner amps
Spirit
1. Welcome page 3
2. Safety Instructions - dos and don’ts 4
3. Controls and Connections - Designation 5
3.1 Top Side 5
3.2 Back Side 6
4. Operation - How to get started 8
4.1 Above all - Check mains 8
4.1a Cable up properly 8
4.2 Gain Structure - Level Adjustment 8
5. Controls and Connections - Functions 8
5.1 Tone Switch - Tone Control - Hp Filter 8
5.2 Eect 9
5.3 Footswitch 10
5.4 Phantom Power 10
5.5 Phones 11
5.6 Send - Return, external loop 11
5.7 Line out 11
5.8 Aux in 11
5.9 DI out 11
5.10 Mains voltage modul 11
6. Technical Data 12
7. Jumper Position 14
8. Blockdiagram 16
manual
2

Welcome to my amps
and thank you for choosing udo roesner amps.
The  75is a two channel combo amplifier made for music
lovers, privates or professionals, that value tone and want their in-
struments sound as they really do.
In all my work in the field of acoustics and musical instruments
over the last decades I have been striving to bridge the gap bet-
ween what we wish for as „natural sound“ and the often modest
sounding reality. Technology just plays a limited role - the room,
the instrument, the own attitude, the individual idea of sound and
even the joy of playing music, everything becomes part of the
recipe to feel good and enchant with <euphony>.
With the Da Capo75 you have acquired a wonderful tool, that will
help you to perfom magic. What and how you play into it will be
played back completely relaxed, with ease and unaltered.
The handling is simple, it is clearly structured and it just does
what it is supposed to do.
Nevertheless, please take a moment to read the following opera-
ting instructions. We have taken an effort to explain the few things
you should know in simple terms so that you, just as relaxed in
dealing with „technology“, can concentrate on what is most impor-
tant: making music, best in company with others.
If you have questions, suggestions or simply wish to get in touch
with us ... with pleasure, please do not hesitate to contact us -
at <[email protected]> - we can do what we do.
Yours musically
udo roesner, 2020
character meets
Technology
3

2. Safety Instructions - dos and don‘ts
The following guidelines shall help minimize the risk of
injury by re or electric shock.
1. Read and understand these safety notes before using
the device and keep them in a safe place.
2. All warnings, instructions and additional texts on the
device are equally important.
3. The device may cause permanent hearing loss. Do not
operate it at a high volume levels or at levels that are
uncomfortable for long periods of time.
4. The device is designed for use in moderate climate and
shall be operated free-standing.
5. The device should be installed in a safe place and secu-
red against falling over.
6. The device should be installed near the socket outlet
thus disconnection the device from mains should be easi-
ly accessible.
7. The device should be located away from heat sources
such as radiators, heat registers or other products that
produce heat.
8. The device should not be installed or used close to
water or if you are wet yourself.
9. The device should not be installed or used close to
strong electromagnetic elds such as large mains trans-
formers, revolving machines, neon illumination etc.
10. Pay attention to an unhindered air circulation around
the amp. Never obstruct air vents or grilles.
11. Do not expose the device to sudden changes in tempe-
rature to avoid malfunction or damage due to moisture
condensation inside. Secure the device to dry out comple-
tely before use again.
12. In keeping with the EMV regulations cables with shiel-
ding and correctly tted connectors must be used for all
signal connections.
ATTENTION
CAUTION
RISK OF ELECTRIC SHOCK - DO NOT OPEN
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR The lightning ash with the arrow head symbol within an
equilateral triangle is intended to alert the user to the
presence of uninsolated „dangerous voltage“ within this
product’s enclosure that may be of sucient magnitude
to constitute a risk of electric shock to persons.
The exclamation point within an equilateral triangle is
intended to alert the user to the presence of important
operating and maintenance (servicing) instructions in
the literature accompanying this product.
4

13. Always use an earthed power supply with the correct
mains voltage. If you are in doubt about the power outlet
ground, have it checked by a qualied technician.
14. Do not lay signal cables parallel to power cables.
15. Protect the power cord from being walked on or
pinched in particular at plugs etc.
16. Cable up the device only when it is powered o.
17. There are no user-serviceable components inside the
unit. To avoid the risk of electric shock the unit must not
be opened. All maintenance, adjustment and repair works
shall be carried out by qualied sta only. Any unautho-
rized tampering will void the 2-year warranty.
18. Only use the correct fuses with the same current
rating and trigger characteristics as replacements. Never
mend fuses! Pull the mains plug before replacing a fuse.
Should a fuse blow again after a short while the device
needs to be checked by qualied sta.
19. Always pull the mains plug before cleaning the unit or
when left unused for a long period of time. Use only dry
cloth for cleaning. Avoid the use of detergents and do not
let any liquids seep into the unit.
20. Do not place any open sources of re, like candles, on
the device.
21. Care should be taken so that objects do not fall onto
the device and liquids are not spilled into the enclosu-
re through openings. Ensure that no objects lled with
liquids, such as vases are placed on the device.
With prudence, common sense and the courage to ask
questions you should build up and enjoy a long and inten-
sive friendship with your amp.
We will do our best to assist you. Do not hesitate to con-
tact us: [e-mail]
ATTENTION
CAUTION
HIGH SOUNDPRESSURE LEVEL
NIVEAU SONORE ÉLEVÉ
ATTENTION
CAUTION
UNIT CAN GET HOT IN OPERATION
PEUT ÊTRE CHAUD EN OPERATION
The sound waves associated with an auricle in an
equilateral triangle are intended to warn the user
that the device can reproduce high sound pressu-
re levels that may result in impaired hearing.
Heat radiation waves rising above a surface in an
equilateral triangle are intended to warn the user
that the surface of the device may become hot
during use.
5

3. Controls and Connections - Designation
3.1 Top Side
hpf
pan
preset
input 2gain tone
channel 2
gain bass treble
level
master
on
middleinput 1 bass treblemiddle
clip
channel 1
line
mic
clip
line
mic
2
3 4
5
1 6
efx
DC 7
5
12
3
4
5
6 7 8
910 11 12 13 14
input: signal input -> TRS 6,3 mm jack plug or XLR-connector
(combi-socket)
line/mic: signal source selector switch
line (jack plug only) for instruments (pickups) and
other line level sources
mic (XLR-connector only) for microphones
clip: overload indicator, +6 dBV headroom
gain: input level control, range 40 dBV
tone: sound lter preset, not active, active
bass: low frequency tone control, 8 dB at 100 Hz
middle: mid frequency tone control, 6 dB at 800 Hz
treble: high frequency tone control, 8 dB at 10kHz
hpf: high pass lter adjustment, 40 Hz to 350 Hz
pan: eect pan control, signal distribution between ch1 and ch2
preset: eect preset select switch
1. reverb short 2. reverb long 3. chorus
4. custom delay 5. my delay* 6. tap n’ delay
level: eect preset level control
on: on/o status indicator
master: master level control
* see page 10
1
5
4
3
2
6
7
8
9
10
11
12
13
14
6

3.2 Back Side
ATTENTION
CAUTION
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
RISK OF ELECTRICAL SHOCK
DO NOT OPEN
power on
designed in germany and france by udo roesner and MARco-labs
udo roesner amps
efx out
DI-out: 1 = gnd 2 = + 3 = neg

aux in DI ch 1
switch
phones line. 2send return line.1 DI ch 2
tip: efx on off
rg: efx adjust
roesner
udo
acoustics
7
5
1 2 3 4 5 6 7
8 9
10
a
cb
phones: headphone signal output, stereo
switch: footswitch connecting socket, TRS
6.3mm jack-socket
efx send: signal output to external eect
efx return: signal input from external eect
line 2: line signal output, high level e.g.
mixing console
line 1: line signal output, -10 dB e.g.
soundcard
aux in: auxiliary input, stereo, TRS 3.5mm
jack socket
DI ch 2: XLR direct out channel 2, balanced
DI ch 1: XLR direct out channel 1, balanced
mains power connector module:
IEC connector: cold appliance socket
mains fuse: 1 AT, slow blow (EU)
2 AT, slow blow (US)
power on: mains power on switch,
illuminated in „on“ mode
8
1
2
3
4
5
6
7
9
10
a
b
c
crossed garbage can:
The labelled product must not be disposed of with
household waste; a bar below the waste bin or a date
indicates whether or when the product was „placed
on the market“ after 13 August 2005.
7

4. Operation - How to get started
4.1 Above All - Check your local mains!
Before connecting to mains, please ensure that your local mains
voltage is suitable to properly operate
the device (e.g. 230V for the EU, 120V for
the US). The relevant specs and safety
symbols are printed on the back-side of
the unit. If you have any doubt, do not
connect the device to mains and consult
a local specialist to verify and assist you.
4.1a Cable up properly - cable clutter
We strongly recommend to solely use proper cable from reputa-
ble cable manufacturers and equivalent connectors. Not only the
sound will clearly benet but trouble shooting will become easier
- any mechanical connection is a potential source of error.
You may need:
-> mono (TS = tip, sleeve), 6.3mm (1/4 inch) jack to jack cables for
your instrument and all line level connections (line out, eect).
-> stereo (TRS = tip, ring, sleeve), 6.3mm (1/4 inch) jack to jack cable
for footswitch and headphone.
-> stereo (TRS = tip, ring, sleeve), 3.5mm (1/8 inch) jack to jack/RCA
cable to connect your playback device to aux in.
-> XLR, 3 pin (1 = ground, 2 = plus, 3 = minus), male - female cable
for microphone.
Connect all cables according to your application before conside-
ring to switch the device on.
Make sure all gains, levels and the master control are in zero- (left
stop) and the tone controls in center-position. You may now switch
the device on. The power switch on the backside is illuminating in
red. The green power control LED on the top will indicate readi-
ness for operation.
4.2 Gain Structure - Level Adjustment
Note:
A little care should be taken to set the signal level ratios conscious-
ly and correctly. The DaCapo is not simply a box with a speaker, it is
a pretty complex arrangement of signal processing stages that all
interact and need to be in peace with each other for best perfor-
mance - the goal surely is: open, real and most of all undistorted
sound reproduction.
Setting levels correctly means putting signal levels neither too
high nor too low - just at best for the circuit stage within the signal
path thus all circuits are ideally addressed
and none is overloaded or distorted. We
have carefully designed the circuits to
make this possible but sound sources dier
(e.g. pickups, they are matter of individual
preference) and gains, EQs and levels allow
manual intervetion.
In practice: First ensure, that master level control is zeroed (left-
stop). Thus when setting the sound level (gain), the signal can not
reach the loudspeaker to generate unexpected noise. Make your
choice of preamp stage making use of line-/mic-switches according
gaininput 1
clip
channel 1
line
mic
Model: DaCapo75
230V AV 50-60 Hz 220W
Fuse: 1A slow
ING197500001
8

to your application (microphone, pickup, lines source) and turn the
gain control clockwise until the clip indicator ashes momentarily
while playing with a strong attack. Go for a little overload, indica-
ted by the red clip-LED, to verify that your signal source can satu-
rate the preamps. Temporary clipping in operation is of no danger
to the device however not recommended. Clipping is detected
and indicated at several points in the signal path as e.g. the active
tone control has an eect on the gain structure.
Note:
There are sources that might not be able to saturate the input sta-
ges of the device. That is a characteristic of the sources and may
result in signal-to-noise ratio limitation or lower power output.
Thereafter reduce the gain slightly to operate the device with win
of additional dynamic headroom and best signal to noise ratio.
Finally set the desired overall volume level with the master level
control. You should be almost perfect with gain and master in a
9:00 o’clock position.
Note:
With a closer look you will nd that there is a dierence in sound
when playing around with gain and master in the range of best
operation. More gain makes the tone more direct, punchy while
less gain softens the tone a bit.
5. Functions and Features
5.1 tone control - tone switch - hpf filter
The 5 is equipped with active, high quality three-
tone
bass treblemiddle
eq channel 1
hpf bass treblemiddle
eq channel 2
band tone controls in each channel. Bass and treble are laid out as
shelving lters. The design reects the ranges of instrument and
voice whilst oering practical, easy to use access to accentuation
of your tone.
With the controls in mid position, i.e. no function, you will already
enjoy a very pleasant, warm and realistic sound. The lters are set
with care and allow intuitive, musical operation with left-turn di-
minishing and right-turn augmenting the frequency ranges around
the lters center frequency. Check technical data below for more
detail. However „Wohlklang“ is basically a question of the overall
concept rather than the task of a single assembly.
Channel 1 oers an additional tone
switch that brightens up the sound
taking out mids and emphasizing the hig-
her ranges. Some instruments, especially
in the lower registers benet from less
focus on mids and a more open, lighter
tone. Some playing styles benet from
this setting too. In conjunction with the
EQ the tone lter allows more detailed midrange accentuation.
Channel 2 is equipped with a high-pass-
lter (hpf) also called bass-cut lter. It
allows signals with frequencies higher
than a threshold to pass and attenuates
the others. The hpf-control adjusts the
threshold between 50 and 350 Hz.
9

It is an essential tool to handle e.g. the
proximity eect in microphone operati-
on. The proximity eect denominates
the phenomenon that a microphone
emphasizes low frequencies the closer
it gets to the sound source (voice,
instrument).
5.2 Eects - efx
The 5has 6 digital eect
presets built in that are accessible by
rotary-switch. You can choose between:
1 = reverb 1 (short) 4 = custom delay/reverb
2 = reverb 2 (long) 5 = my delay (udo roesner’s delay preset)
3 = chorus 6 = tap n’ delay
Efx-pan control sets the amount of signal level from channel 1 and
2 directed to a) the internal eect input (quasi internal send) and
b) the send of the efx-loop (backside, left stop = no signal) while
efx-level distributes the eect signal to channel 1 or 2 with center
position being distributed even (quasi an internal return).
left stop: signal channel 1 to eect only
center position: signal channel 1 and 2 to eect evenly
right stop: signal channel 2 to eect only
Efx level has no inuence on the return of the eects loop.
Furthermore an additional eect device may be connected to
the 5 via efx send-return eects loop on the back-
side (send to input, return to output of the additional device).
The intensity of the external eect has to be adjusted at the
external eects unit.
5.3 Footswitch
Any standard, latching double-footswitch (2 x on-/o) can be
connected to the switch-socket at the backside of the amplier by
stereo (TRS) connector. Switch one (connected to tip) will switch
the internal eect on/o while switch two (connected to ring) will
control the delay-time of „tap n’ delay“ (factory setting) in the way
that the time dierence between two foot-taps denes the delay
time in a time window between 0 and 1000 milliseconds. This fac-
tory setting can be altered by changing jumper position 11 (JP 11).
Thereafter switch two will on/o the external eect.
factory setting is: switch 1: eect on/o
switch 2: tap n’ delay mode
jumper setting: switch 1: eect on/o
switch 2: ex. eect on/o
5.4 Phantom power
Condenser microphones requiring 48V phantom power can be
connected to the XLR-sockets of both channels as phantom power
is provided by factory setting. It can be deactivated by internal
jumper if required. In case you use the microphone preamp with a
stereo jackplug (TRS) there is no phantom power provided.
high pass filter - mode of operation
frequency Hz
gain
in dB
0
-3
50 300 1.000 20.000
DOC_HPF-2019-01
pan
preset
level
2
3
5
1 6
efx
4
10

5.5 phones
This output allows a stereo headphone to be connected. When
connected the speaker is muted and master control sets the over-
all volume.
(!) Note: Please use headphones with stereo
jack plugs (TRS) for operation only.
5.6 send - return, external eect loop
The device is equipped with an additional output (send) and input
(return) that operate as a loop allowing e.g. an external eect-unit
to be connected and used. Send and return are mono and the loop
is parallel to the signal path to keep the original signal unaected.
The pan control will work on both eects, internal and external, at
the same time in the same way.
5.7 line out - line 1, line 2
The device oers two line outs that dier in output level. Line 2
delivers a standard line level suitable for being connected to e.g.
mixing consoles. Line 1 has less output and allows e.g. a soundcard
to be connected directly with less risk of distorting the digital
input of the soundcard.
5.8 aux in
Aux-in is an additional 3,5mm TRS stereo input to connect your
playback device to. Left and right channel of your playback device
are mixed and directly forwarded to the power amp.
5.9 DI ch 1, DI ch 2
The device oers two equally leveled electronically balanced DI-
outs to make the individual channel preamp signals available. This
enables better and more interference-free signal processing of the
individual channels. Due to intended strict channel separation the
DI outs have to be dry, without eect.
5.10 mains voltage input module
The mains-supply relevant parts are combined in the mains volta-
ge input module:
IEC mains power cable connector,
fuse holder with spare fuse and
illuminated mains switch.
... and now have fun playing music and enjoy the sound of the
5.
11

INPUTS:
=> channel 1 and 2
switchable instrument or microphone input as combi-socket, XLR + jack ¼”
(6.35 mm) and clip indicators, min. dynamic headroom: 8 dB
-> line mode
high impedance jack input for instruments (pick-ups directly), unbalanced and
line-level sources
impedance:2.2 Meg
sensitivity: 22 mV (–33 dBV) (high/low attenuator: –10 dB via jumper)
equivalent input noise: A-weighted: 1 uV (–120 dBV)
-> mic mode
XLR- , balanced and stereo jack socket, unbalanced
impedance: XLR, balanced: 1.2 kOhm
impedance: jack, unbalanced: 2.7 kOhm
sensitivity: 3.3 mV (–50 dBV)
voice lter: –10 dB at 270 Hz (referred to 10 kHz)
equivalent input noise: A-weighted: 0.8 uV (–122 dBV)
phantom power: (XLR only): 48 V, max. 10 mA, short-circuit protected
=> return: unbalanced jack input, ¼” (6.35 mm), pre-master
sensitivity: 320 mV (–10 dBV)
impedance: 19.7 kOhm (note: impedance changes to 4.7 kOhm when external
eect is switched OFF)
=> aux in: TRS stereo input, 3.5mm
OUTPUTS:
=> phones: headphones, jack socket, stereo, L/R connected,
¼” (6.35 mm)
input Impedance: 470 Ohm (common for L and R)
(!) Please note:
Use TRS (Stereo Jacks) only. Does not work with mono jacks!
When plugged in, internal speaker is muted!
=> send: jack socket, unbalanced, ¼” (6.35 mm), pre master,
output voltage: 1.4 V (+3 dBV)
=> line out 1 and 2: jack socket, unbalanced, preamp out, ¼” (6.35 mm),
post eect, post EQ and master
output voltage 2: 1.74 V (+3 dBV)
output voltage 1: 0.33 V (-4.6 dBV)
=> DI-out 1 and 2: balanced XLR socket, pre/post EQ (sitchable by jumper)
post eect and master
1 = ground 2 = positive 3 = negative
dierential output voltage: 140 mV (–17 dBV)
FOOTSWITCH
=> footswitch: TRS jack socket ¼” (6.35 mm) to connect latching dual foot
switch.
tip = built-in eect on/o, ring = parameter adjust or additional eect on/o ,
sleeve = common (ground)
(!) Please note:
Eect is OFF when the footswitch is ON.
EQ - Tone Controls
=> channel 1:
tone: –3 dB at 700 Hz, +7 dB at 8 kHz
bass: 8 dB at 100 Hz (shelf type)
middle: 6 dB at 800 Hz
treble: 8 dB at 10 kHz (shelf type)
6. Technical Data
12

Notes
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
=> channel 2:
hpf lter: 40Hz to 350 Hz,
bass: 8 dB at 100 Hz (shelf type)
middle: 6 dB at 800 Hz
treble: 8 dB at 10 kHz (shelf type)
EFFECTS
eect presets: 1: reverb short, 2: reverb long, 3: chorus,
4: custom delay, 5: my delay, 6: tap n’ delay,
external eect: parallel eect loop (see also send and return)
efx pan: blends both internal and external eects between
channels 1 and 2,
POWER SECTION
=> power amp: 75 W / 4 ohm, DMOS, monolithic I.C. dynamic range,
A-weighted: 92 dB
=> analog signal processing: dedicated equalizer, subsonic lter,
adaptive peak limiter
=> limiter threshold: 60 W
=> speaker system: 8” (200 mm) twin cone full-range speaker, bass
reex enclosure
=> mains power: mains voltage (depending on model):
100, 120, 230, or 240 V AC, 50–60 Hz
=> power consumption: max. 200 W
=> mains fuse: 5 x 20 mm T 1A L /250 V for 230 and 240 V
5 x 20 mm T 2A L /250 V for 100 and 120 V
GENERAL
=> cabinet: 12 mm (0.47”) plywood
=> nish: polyester black spatter nish
=> dim: 265 mm (10.43“) height, 325 mm (12.8“) width,
245 mm (9.65“) depth
=> weight, net: 7.5 kg (16.5 lbs)
13

1
23
5
4
8
7
6
10 9
11
JUMPER SETTINGS:
=> attenuation:
JP 1: line ch1 -> high (+9.5dB) low (0dB). default: high
JP 2: line ch2-> high (+9.5dB) low (0dB). default: high
JP 3: mic ch2 -> high (+12.5dB) low (0dB). default: high
JP 4: mic ch2 -> high (+12.5dB) low (0dB). default: high
=> voice lter:
JP5: mic ch1 on/o. default: on
JP6: mic ch2 on/o. default: on
=> phantom power
JP7: phantom power ch1 on/o . default: on
JP8: phantom power ch2 on/o. default: on
=> direct out
JP9: DI ch 1 pre or post EQ. default: pre
JP10: DI ch2 pre or post EQ. default: pre
Footswitch
JP11: ring -> internal eect parameter or
-> external eect loop on/o.
(!) default: internal eect parameter.
jumper settings may only be carried out by qualied
service personnel and when the unit is disconnected
from mains power supply. It has to be opened!
7. Jumper positions
14

Block Diagram V-1
Da Capo 75
Sheet: 1/1
190626 TM
acoustics
roesner
udo
8. Block diagram
15

.udo roesner amps www.udo-amps.com
MARco-labs s.a.s.
udo roesner amps are designed and developed in
Germany and France by udo roesner and MARco-labs.
Produced in Indonesia with pleasure and great care.
acoustics
roesner
udo
ML_DMA-DC75-UK-200417