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The current stock pre amp tubes from the far right to left:    

 

 
V1 

( input stage ) and 

V2

 ( the phase inverter position ), are either Sovtek 12AX7 LPS or

 

the 

re-issue

 

Sovtek Mullard 12AX7. The LPS is an excellent sounding 12AX7 and are used in all 

Komet amplifier models. With this factory stock  tube compliment, the Komet

Songwriter

 

sounds  powerful,  complex  and  detailed.    The  distortion  is  balanced  and  harmonically  rich.  
Other brands of audio tubes will operate in your Komet

 

amplifier.  But there are much better 

tubes available than the stock, modern available tubes.  If you want more info, read on….  

 
 

 
In the Golden Age of tube technology 

( 1950’s, 60’s and early 70’s )

, - virtually all tubes were 

manufactured by European or American companies such as Mullard, Brimar, Amperex, 
Telefunken, Valvo, Tung-Sol, RCA, and others.  Unfortunately, all of these companies have 
discontinued audio tube production.  Very few of these brands remain available from military 
stock, repair shops, etc.  These tubes are generally referred to as “ 

New  - Old Stock 

” 

a.k.a.

  

N.O.S.  

 

 
 
The  best  of  the  n.o.s.  tubes  are  in  every  aspect  superior  to  any  currently  modern 
manufactured tube.  N.O. S. tubes are very expensive and are rapidly disappearing.  You may 
decide  that  they  are  worth  the  expenditure  to  enhance  the  performance  of  your  amp.    The 
improvement gained by a proper tube selection is quite noticeable in a refined amplifier such 
as a Komet

.  You may not want to use them for practicing, but save them for recording and 

important  performances. 

Remember:

  always  purchase  from  a  reputable  n.o.s.  tube  dealer. 

The following contains brand recommendations based on our experience.  
 

 
Mullard / Valvo  EL 84

 / 

6BQ5

   The yardstick used most to measure all EL 84

by.  Their 

internal construction and sonic quality are superior to modern available EL84s.  Many were 
manufactured  and  distributed  under  different  brands  or  labels.  Valvo,  Mullard,  Brimar, 
Amperex, & Telefunkin are excellent n.o.s. choices. 

 Note:  

PLEASE READ CAREFULLY 

the 

Biasing Section

 on next page of this manual. 

 

 
ECC 83, 12AX7, 7025, 

and

 CV4004

 are interchangeable. There are many brands to choose 

from.    The  tone  and  clarity  can  vary  between  each  of  these  tube  types  and  brands.    We 
generally  prefer  the  European  brands:  Telefunkens,  Brimars,  Mullards,  Amperex,  Phillips 
Mini  Watts,  etc.    Each  amplifier  has  its  own  personality  that  may  be  complimented  by  a 
specific selection or manufacturer 

( brand )

 of audio tubes.  You may want to research for more 

information on n.o.s. tubes before you make a purchasing decision.  

Note:

 when purchasing 

tubes,  be  careful  not  to  confuse  modern  re-issue  audio  tubes,  like  the  re-issue  Mullard, 
Genelex, Tung-Sol, etc. with original and more expensive n.o.s. audio tubes.    

 
 

Please note:

  you may find that some new, used, or even 

n.o.s.

 preamp tubes may be too  

  microphonic 

“  for  the  first  gain  stage  (

  V1 

)  of  a  Komet

 

amplifier.    A  microphonic 

preamp tube is a condition in which a tube will absorb mechanical vibration and amplify it 
into the audible range.   

( continued ) 

 

 
 
Copyright 2000-2012, Riverfront Music, L.L.C. d.b.a. Komet

Amplification.  May not be reproduced in any form without express written 

consent from Riverfront Music, L.L.C. d.b.a. Komet

Amplification. 

Summary of Contents for Songwriter

Page 1: ...iter Owner s Manual Copyright 2000 2012 Riverfront Music L L C d b a Komet Amplification May not be reproduced in any form without express written consent from Riverfront Music L L C d b a Komet Amplification ...

Page 2: ...they are measured in nanoseconds they can cause considerable damage to electronic equipment Electrical surges can damage equipment by burning or fusing internal wires or by gradually over time wearing down the device s internal components The best way to prevent damage is to unplug your amplifier when not in use NOTE Devices such as refrigerators and air conditioners require large amounts of energ...

Page 3: ...urn the jewel lens cap counterclockwise and remove Now the bulb is exposed Using the tips of your fingers gently push and turn the bulb counterclockwise extract bulb and replace Note Your amplifier will continue to operate with no problem with a shorted bulb or with no bulb at all 4 Bass Control controls low end bass range frequencies 5 Volume Control adjusts clockwise the overall level and gain o...

Page 4: ...ance you are using 4 8 and 16 Ohm settings are available 5 Output Jacks standard inch speaker jacks which accommodate any quality standard speaker cable Note never use a shielded guitar cable as a speaker cable You can severely damage an amplifier 6 Tube Chart Displays the placement of the power and pre amp tubes TUBE CHOICES FOR THE KOMET SONGWRITER CAUTION Always allow the power and pre amp tube...

Page 5: ...nt performances Remember always purchase from a reputable n o s tube dealer The following contains brand recommendations based on our experience Mullard Valvo EL 84 6BQ5 The yardstick used most to measure all EL 84s by Their internal construction and sonic quality are superior to modern available EL84s Many were manufactured and distributed under different brands or labels Valvo Mullard Brimar Amp...

Page 6: ...can be found on line from many vintage tube retailers This easy to use device guarantees that your pre amp tube and 6BQ5 EL 84 power tube pins will be straight and aligned for socket insertion NOTE Komet Amplification s Warranty will not cover damage done to a tube socket s insertion pins from forced or accidental mis alignment and or bent crimped insertion pins BIASING THE KOMET SONGWRITER The Ko...

Page 7: ...et Amplification speaker cabinet lineup is another excellent option Please see our website www kometamps com for full speaker cabinet information Whichever cabinet you do use make sure you set the impedance selector correctly If you use two cabinets keep in mind that the outputs are in parallel This means that if you are operating the amplifier on two 16 Ohm cabinets you must set the amplifier s i...

Page 8: ...er need servicing or repair please make arrangements with us to have your amp shipped back to Komet Amplification TROUBLESHOOTING When troubleshooting a problem we recommend that you remove all effects pedals and only go direct with your guitar and guitar cable into the amplifier Also remove any attenuation device from amp to speaker cabinet This way you can easily and quickly rule out or discover...

Page 9: ...g Hissing Feedback or Crackling sound Most likely a bad pre amp tube Pre amp tubes can develop problems over their life span They may operate flawlessly over time and they may also test fine on a tube tester but for what seems like for no reason they can suddenly begin to make a hissing sound or develop filament humming noise or exhibit a crackling sound They can also begin to feedback or have mic...

Page 10: ...ment glow on the top and bottom of the power tubes for the center plates If the plates in the center of the tube are glowing a dull red or are cherry colored from the center see reference photo below then the power tubes are under biased and will need to be replaced with a lower IP current drawing set If not replaced they will fail and short out in short order and the H T fuse will blow Copyright ...

Page 11: ...spare and is voiced to cut through the band mix Give yourself and your new amp a little time to get to know each other No matter how good it sounds right out of the box your amp will break in and improve tremendously after being played over time The harmonic complexity will continue to improve the tone will sweeten up and become even more fluid and resonant Have fun Thank you for purchasing our pr...

Page 12: ...labeled with a number for the tube s required placement within the amp Please make sure to install each labeled tube into the correct corresponding tube socket V7 through V3 are for the EL 84 power tubes V2 and V 1 are for the 12AX7 pre amp tubes Gently install each tube in the correct corresponding tube socket Please note each tube s pin configuration must be properly and perfectly aligned with t...

Page 13: ... than thirty days Komet Amplification shall notify the customer accordingly This warranty shall be void and of no force of effect in the event a covered product has been modified in design or function or subjected to abuse misuse which includes operation of amplifier with incorrect tube types mishandling or unauthorized repair Further product malfunction or deterioration due to normal wear is not ...

Page 14: ...they are measured in nanoseconds they can cause considerable damage to electronic equipment Electrical surges can damage equipment by burning or fusing internal wires or by gradually over time wearing down the device s internal components The best way to prevent damage is to unplug your amplifier when not in use NOTE Devices such as refrigerators and air conditioners require large amounts of energ...

Page 15: ...in series parallel for 16 Ohms Note Komet Amplification recommends using a 16 Ohm load with their amplifiers for the best sonic results Copyright 2000 2012 Riverfront Music L L C d b a Komet Amplification May not be reproduced in any form without express written consent from Riverfront Music L L C d b a Komet Amplification ...

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