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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

 

 

Echolette MK I

31

Содержание MK I

Страница 1: ...Echolette MK I Tube amp head user manual...

Страница 2: ...Musikhaus Thomann Thomann GmbH Hans Thomann Stra e 1 96138 Burgebrach Germany Telephone 49 0 9546 9223 0 E mail info thomann de Internet www thomann de 07 06 2016 ID 344876...

Страница 3: ...ls 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 BI...

Страница 4: ...9 Protecting the environment 36 Table of contents Tube amp head 4...

Страница 5: ...s 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 m...

Страница 6: ...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 Pers...

Страница 7: ...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 Switc...

Страница 8: ...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...

Страница 9: ...Warning signs Type of danger Warning high voltage Warning danger zone General information Echolette MK I 9...

Страница 10: ...hysical 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 responsibl...

Страница 11: ...unt 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 tectiv...

Страница 12: ...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 m...

Страница 13: ...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 occ...

Страница 14: ...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 Feature...

Страница 15: ...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 electr...

Страница 16: ...5 Connections and controls Front panel Connections and controls Tube amp head 16...

Страница 17: ...nd 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 t...

Страница 18: ...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...

Страница 19: ...efore 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...

Страница 20: ...Rear panel Connections and controls Tube amp head 20...

Страница 21: ...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 f...

Страница 22: ...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 c...

Страница 23: ...ance 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 supp...

Страница 24: ...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...

Страница 25: ...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 especia...

Страница 26: ...Maintenance Tube amp head 26...

Страница 27: ...cted 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 m...

Страница 28: ...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 Aft...

Страница 29: ...6 3 Adjusting the BIAS Maintenance Echolette MK I 29...

Страница 30: ...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...

Страница 31: ...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 re...

Страница 32: ...4 or 6L6 optional Pre stage tubes 5 ECC83 standard 12AX7 7025 ECC81 ECC82 12AY7 12AU7 12AT7 optional Loudspeaker connection options 1 4 1 8 1 16 2 8 2 16 Power consumption 70 W at 1 8 output power Ope...

Страница 33: ...Dimensions W D H 570 mm 250 mm 260 mm Weight 8 3 kg Technical specifications Echolette MK I 33...

Страница 34: ...tors 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...

Страница 35: ...terfering 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 mo...

Страница 36: ...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 D...

Страница 37: ...Notes Echolette MK I 37...

Страница 38: ...Notes Tube amp head 38...

Страница 39: ......

Страница 40: ...Musikhaus Thomann Hans Thomann Stra e 1 96138 Burgebrach Germany www thomann de...

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