Echolette MK I User Manual

Echolette MK I

Tube amp head

user manual

Musikhaus Thomann
Thomann GmbH
Hans-Thomann-Straße 1
96138 Burgebrach
Germany
Telephone: [phone]
E-mail: [e-mail]
Internet: www.thomann.de

07.06.2016, ID: 344876

Table of contents

1 General information................................................................................................................................. 5

1.1 Further information........................................................................................................................... 6

1.2 Notational conventions.................................................................................................................... 7

1.3 Symbols and signal words............................................................................................................... 8

2 Safety instructions.................................................................................................................................. 10

3 Features....................................................................................................................................................... 14

4 Notes on use............................................................................................................................................... 15

5 Connections and controls................................................................................................................... 16

6 Maintenance.............................................................................................................................................. 23

6.1 Replacing the main fuse................................................................................................................ 24

6.2 Replacing tubes................................................................................................................................ 25

6.3 Adjusting the BIAS........................................................................................................................... 29

7 Technical specifications....................................................................................................................... 32

8 Plug and connection assignment.................................................................................................... 34

Table of contents

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9 Protecting the environment.............................................................................................................. 36

Table of contents

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1 General information

This manual contains important instructions for the safe operation of the unit. Read and follow
the safety instructions and all other instructions. Keep the manual for future reference. Make
sure that it is available to all those using the device. If you sell the unit please make sure that
the buyer also receives this manual.

Our products are subject to a process of continuous development. Thus, they are subject to
change.

General information

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1.1 Further information

On our website (www.thomann.de) you will find lots of further information and details on the
following points:

Download This manual is also available as PDF file for you to download.

Keyword search

Use the search function in the electronic version to find the topics of
interest for you quickly.

Online guides

Our online guides provide detailed information on technical basics
and terms.

Personal consultation For personal consultation please contact our technical hotline.

Service

If you have any problems with the device the customer service will
gladly assist you.

General information

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1.2 Notational conventions

This manual uses the following notational conventions:

The letterings for connectors and controls are marked by square brackets and italics.
Examples: [VOLUME] control, [Mono] button.

The individual steps of an instruction are numbered consecutively. The result of a step is
indented and highlighted by an arrow.

Example:

1. Switch on the device.

2. Press [Auto].

ð

Automatic operation is started.

3. Switch off the device.

Letterings

Instructions

General information

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References to other locations in this manual are identified by an arrow and the specified page
number. In the electronic version of the manual, you can click the cross-reference to jump to
the specified location.

Example: See Ä ‘Cross-references’ on page 8.

1.3 Symbols and signal words

In this section you will find an overview of the meaning of symbols and signal words that are
used in this manual.

Signal word Meaning
DANGER! This combination of symbol and signal word indicates an

immediate dangerous situation that will result in death or
serious injury if it is not avoided.

NOTICE! This combination of symbol and signal word indicates a pos‐

sible dangerous situation that can result in material and
environmental damage if it is not avoided.

Cross-references

General information

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Warning signs Type of danger

Warning – high-voltage.

Warning – danger zone.

General information

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2 Safety instructions

This device is intended to be used for amplification and playback of signals from musical
instruments with electromagnetic pickups. Any other use or use under other operating condi‐
tions is considered to be improper and may result in personal injury or property damage. No
liability will be assumed for damages resulting from improper use.

This device may be used only by persons with sufficient physical, sensorial, and intellectual
abilities and having corresponding knowledge and experience. Other persons may use this
device only if they are supervised or instructed by a person who is responsible for their safety.

DANGER!
Danger for children

Ensure that plastic bags, packaging, etc. are disposed of properly and are not
within reach of babies and young children. Choking hazard!

Ensure that children do not detach any small parts (e.g. knobs or the like) from
the unit. They could swallow the pieces and choke!

Never let children unattended use electrical devices.

Intended use

Safety

Safety instructions

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DANGER!
Electric shock caused by high voltages inside

Within the device there are areas where high voltages may be present.
Completely disconnect the device from the power supply before you open or

remove covers. Mount all covers and attach them firmly before connecting the
device again.

DANGER!
Electric shock caused by short-circuit

Always use proper ready-made insulated mains cabling (power cord) with a pro‐
tective contact plug. Do not modify the mains cable or the plug. Failure to do so
could result in electric shock/death or fire. If in doubt, seek advice from a regis‐
tered electrician.

Safety instructions

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NOTICE!
Risk of fire

Do not cover the device nor any ventilation slots. Do not place the device near
any direct heat source. Keep the device away from naked flames.

NOTICE!
Operating conditions

This device has been designed for indoor use only. To prevent damage, never
expose the device to any liquid or moisture. Avoid direct sunlight, heavy dirt, and
strong vibrations.

Safety instructions

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NOTICE!
Power supply

Before connecting the device, ensure that the input voltage (AC outlet) matches
the voltage rating of the device and that the AC outlet is protected by a residual
current circuit breaker. Failure to do so could result in damage to the device and
possibly injure the user.

Unplug the device before electrical storms occur and when it is unused for long
periods of time to reduce the risk of electric shock or fire.

Safety instructions

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3 Features

n Full tube guitar amp head
n Drive channel (D-channel)
n Clean channel (F-channel)
n Serial FX loop with send / return level
n Two output stage tubes, five pre-stage tubes
n Class AB push-pull output stage

Features

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4 Notes on use

Unpack and carefully check that there is no transportation damage before using the unit. Keep
the equipment packaging. To fully protect the device against vibration, dust and moisture
during transportation or storage use the original packaging or your own packaging material
suitable for transport or storage, respectively.

Handle the unit with care. The built-in tubes are especially in heated state very sensitive to
vibration, e.g. during transport and setting the device down.

The pre-stage tubes can easily be exchanged without any detailed specialist knowledge. To
exchange the output stage tubes, however, specialist knowledge in the field of electrical engi‐
neering is required. If in doubt, ask an authorised, qualified professional to replace these tubes
for you.

After every exchange of the output stage tubes, the BIAS must always be adjusted. The process
for exchanging the installed tubes and adjusting the BIAS is described in

Ä

Chapter 6 ‘Mainte‐

nance’ on page 23 more detail in .

All repairs and servicing of electrical components must only be performed by authorised per‐
sonnel.

Notes on use

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5 Connections and controls

Front panel

Connections and controls

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1 [INPUT]

Input socket for instrument cable, designed as a 6.35 mm jack socket (mono).

2 [F CHANNEL]

Clean channel for full, warm sound with lots of headroom, especially suitable for overdrive and distortion effects.

[Gain]

Gain signal for the clean channel. Amplifies the input signal and generates a slightly compressed sound.
[Treble], [Middle], [Bass]

Control to adjust the settings of the 3-band equaliser in the clean channel.

[Volume]

Control to adjust the volume of the clean channel. At high volume, the output stage tubes start to distort the sound.

3 [D CHANNEL]

Drive channel (also known as the lead or dirty channel) for “clean” sound, warm crunch sound and rock sounds. The
sound generated also depends on the input signal, i.e. on the guitar used and the sound settings (in the case of
active instruments).

Connections and controls

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[Gain]

Gain signal for the drive channel. Amplifies the input signal and generates a slightly compressed sound.
[Treble], [Middle], [Bass]

Control to adjust the settings of the 3-band equaliser in the drive channel.

[Volume]

Control to adjust the volume of the drive channel. At high volume, the output stage tubes start to distort the sound.
From a certain setting, the volume is no longer increased but instead the distortion becomes more intense.

4 [Presence]

Controller to raise or lower the threshold limiter of the satellite speaker in the upper frequency range.

5 [F | D]

Toggle switch between the clean and drive channel.

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6 [Standby]

With this switch, the high voltage is switched to the tubes (upper switch position). The amp is then ready for opera‐
tion. If the high voltage is switched off (lower switch position), the amp is in standby mode.

To protect the tubes, the satellite speaker should be switched to standby around one minute before switching on the
amp. After this, the amp can be switched to ready mode with the [Standby] switch.

Even during short breaks in play, we recommend switching the amp head to standby without switching it off com‐
pletely with the [Power]switch.

Before switching off the amp head, always switch the high voltage off first using the [Standby] switch!

7 [Power]

Main switch to turn the device on/off.

8 Power indicator. This LED glows as soon as voltage is applied to the device.

Connections and controls

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Rear panel

Connections and controls

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9 IEC chassis plug with fuse holder.

10 [SPEAKER]

Connection sockets for loudspeaker boxes (designed as 6.35-mm jack sockets) with the following connection options:
1 × 16 Ω Connect a 16 Ω loudspeaker box to this socket.
1 × 8 Ω or 2 × 16 Ω Connect either one 8 Ω loudspeaker box or two loudspeaker boxes of 16 Ω each to these parallel

sockets. The parallel switching means that both sockets can be used equally.

1 × 4 Ω or 2 × 8 Ω Connect either one 4 Ω loudspeaker box or two loudspeaker boxes of 8 Ω each to these parallel

sockets. The parallel switching means that both sockets can be used equally.

Before switching on the amp head, ensure that a loudspeaker box is connected. Otherwise the device may be damaged.

11 [FOOTSWITCH]

Connection socket for a footswitch for toggling between the clean and drive channel (designed as a 6.35-mm jack socket).
As soon as you connect a footswitch to the amp head, the front channel selector is temporarily disabled.

12 [FX LOOP]

Effect section. The two connection sockets (6.35 mm jack sockets) can be used to interloop as many effects as you want
between the pre-stage and output stage. If you do not connect any effect device, set the two Level controllers to the 3
o’clock position.

Connections and controls

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[Return | Level] Rotary controller, controls the signal strength from the effect device to the amp and can also be used

as a master volume controller.

[Return] Input socket for connecting an effect device (or the last effect in an effects chain) or an external pre-

amp. As soon as a cable is connected, the pre-stage signal is separated from the amp's output stage
signal.

[Send] Output jack. This connection socket is used to feed the signal from the amp back into the input of the

effect device. This output can also be used to connect an external output stage. The pre-stage is not
separated from the output stage signal in this case.

[Send | Level] Rotary controller, controls the signal strength from the amp to the effect device or external output

stage and can also be used as a master volume controller.

Connections and controls

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6 Maintenance

DANGER!
Electric shock caused by high voltages inside

Inside the device, a voltage of up to 500 V may be present, even if the device is
switched off.

The maintenance measures described below require specific electrical engi‐
neering expertise and must only be carried out by appropriately qualified per‐
sonnel.

Disconnect the device completely from the power supply before opening or
removing any covers. Only reconnect the device once the covers have been fully
reattached and are firmly secured in place.

Maintenance

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NOTICE!
Possible damage from dirt or fingerprints.

Dirt or fingerprints can destroy the glass pistons in the tubes.
Never hold the glass pistons directly with your fingers. Use clean gloves or a clean

cloth made from lint-free material.

6.1 Replacing the main fuse

The fuse holder for the main fuse is located below the IEC chassis plug. When replacing the
main fuse, ensure that the replacement fuse has the required parameters (see printed informa‐
tion on the fuse holder).

Faulty fuses must never be bridged!
If the device continues to not function after replacing the fuse, ask a specialist workshop to

resolve the problem.

Maintenance

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6.2 Replacing tubes

Pre-stage tubes V1 … V5 can easily be replaced without any detailed specialist knowledge.
After a replacement, no further adjustment work is required in this case.

Pre-stage tubes of type ECC83, 12AX7 and 7025 are permitted. Also permitted - however with
less gain with the same controller position - are pre-stage tubes of type ECC81, ECC82, 12AY7,
12AU7, 12AT7.

With pre-stage tube V1 especially, high quality must be ensured to avoid unwanted noise and
microphonics.

The illustration below shows the position of tubes V1 … V7 on the amp.

Replacing pre-stage tubes

Maintenance

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Maintenance

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Name Function

V1 First stage for both channels.
V2 Second stage for both channels.
V3 Third and fourth stage for the D-channel.
V4 FX Loop.
V5 Phase inverter.
V6 End stage tube.
V7 End stage tube.

1. Make sure that the device is turned off, disconnected from the mains and completely

cooled down. The minimum wait time after disconnecting the voltage supply is ten
minutes.

2. Remove the metal caps and remove the old tubes with a gentle, even pulling motion,

gently rocking the tubes back and forth, out of the bases.

3. Push the pins of the new tubes with gentle, even pressure and slight back and forth

movements into the base and place the metal caps on the tubes.

Maintenance

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The replacement of V6 and V7 output stage tubes requires specific electrical engineering
expertise and must only be carried out by appropriately qualified personnel. Inside the amp, a
voltage of up to 500 V may be present, even if the device is switched off!

Output stage tubes of type KT66 and other common output stage tubes, such as EL34, 6L6 or
5881, are permitted.

After changing the output stage tubes, the BIAS must be adjusted (see Ä Chapter 6.3 ‘Adjusting
the BIAS’ on page 29).

Replacing output stage tubes

Maintenance

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6.3 Adjusting the BIAS

Maintenance

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13 Resistors R53 and R54.
14 Fuse F1.
15 Potentiometer for setting the BIAS.

1. Make sure that the device is turned off, disconnected from the mains and completely

cooled down. The minimum wait time after disconnecting the voltage supply is ten
minutes.

2. Remove the cover on the reverse and pull the amp out of the housing.

3. Using a multimeter, check that fuse F1 is OK.

4. Connect a loudspeaker to the appropriate output and switch the device on using the

main [Power] switch.
Ensure that no instruments are connected to the [INPUT] .

5. Turn the [Return | Level] controller to “0”.

6. Turn the potentiometer to set the BIAS all the way in a clockwise direction.

7. Using the [Standby]switch, apply high voltage to the tubes and wait for around a minute

until the tubes have stabilised.

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8. Using a voltmeter, measure the drop in voltage at the two resistors R53 and R54.

During measurement, turn the potentiometer anti-clockwise until the voltmeter displays
a value of 25 mV. This corresponds to a value of 25 mA. This current is flowing through
each of the two output stage tubes.

A difference of 2 … 3 mV is tolerable. If the difference is greater than 3 mV between the
two measured values, the output stage tubes are not well-tuned with each other and
must be replaced.

9. Leave the amp running for 15 minutes and then repeat the measurement. If no further

adjustments are needed, switch the device off, disconnect it from the mains and leave it
to cool down completely.

10. After the minimum wait time (ten minutes after disconnecting the voltage supply), place

the amp back in the housing and fit the cover on the reverse.

Maintenance

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7 Technical specifications

Output power of AB push-pull output stage 35 W
Output stage tubes 2 × KT66 (standard), EL34 or 6L6 (optional)
Pre-stage tubes 5 × ECC83 (standard), 12AX7, 7025, ECC81, ECC82, 12AY7, 12AU7, 12AT7

(optional)

Loudspeaker connection options 1 × 4 Ω

1 × 8 Ω
1 × 16 Ω
2 × 8 Ω

2 × 16 Ω
Power consumption 70 W at 1/8 output power
Operating supply voltage

230 V 50 Hz
Fuse 5 mm × 20 mm, 2 A, 250 V, slow-blow

Technical specifications

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Dimensions (W × D × H) 570 mm × 250 mm × 260 mm
Weight 8.3 kg

Technical specifications

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8 Plug and connection assignment

This chapter will help you select the right cables and plugs to connect your valuable equip‐
ment in such a way that a perfect sound experience is ensured.

Please note these advices, because especially in ‘Sound & Light’ caution is indicated: Even if a
plug fits into the socket, an incorrect connection may result in a destroyed power amp, a short
circuit or ‘just’ in poor transmission quality!

Unbalanced transmission is mainly used in semi-professional environment and in hifi use.
Instrument cables with two conductors (one core plus shielding) are typical representatives of
the unbalanced transmission. One conductor is ground and shielding while the signal is trans‐
mitted through the core.

Unbalanced transmission is susceptible to electromagnetic interference, especially at low
levels, such as microphone signals and when using long cables.

In a professional environment, therefore, the balanced transmission is preferred, because this
enables an undisturbed transmission of signals over long distances. In addition to the conduc‐
tors ‘Ground’ and ‘Signal’, in a balanced transmission a second core is added. This also transfers
the signal, but phase-shifted by 180°.

Introduction

Balanced and unbalanced trans‐
mission

Plug and connection assignment

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Since the interference affects both cores equally, by subtracting the phase-shifted signals, the
interfering signal is completely neutralized. The result is a pure signal without any noise inter‐
ference.

1 Signal
2 Ground, shielding

1 Signal (in phase, +)
2 Signal (out of phase, –)
3 Ground

1/4" TS phone plug (mono,
unbalanced)

1/4" TRS phone plug (mono, bal‐
anced)

Plug and connection assignment

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9 Protecting the environment

For the transport and protective packaging, environmentally friendly materials have been
chosen that can be supplied to normal recycling.

Ensure that plastic bags, packaging, etc. are properly disposed of.
Do not just dispose of these materials with your normal household waste, but make sure that

they are collected for recycling. Please follow the notes and markings on the packaging.

This product is subject to the European Waste Electrical and Electronic Equipment Directive
(WEEE). Do not dispose with your normal household waste.

Dispose of this device through an approved waste disposal firm or through your local waste
facility. When discarding the device, comply with the rules and regulations that apply in your
country. If in doubt, consult your local waste disposal facility.

Disposal of the packaging mate‐
rial

Disposal of your old device

Protecting the environment

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Notes

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Notes

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Musikhaus Thomann · Hans-Thomann-Straße 1 · 96138 Burgebrach · Germany · www.thomann.de