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Written by Administrator   
Friday, 26 May 2006
Place holder for my current project -> Derailment! This is an amp that was designed by Jones Amplification. It is a single ended Trainwreck with 2 tubes (12AX7 and 6GW8/ECL86). I am adding the following modifications to it:
  • Master volume
  • Switch to bypass the third gain stage (the clipping stage). This switch will also change the biasing of the second stage to make it closer to a fender tweed one.
  • Variable cut stage (to change it from a 1k to 26k and everything in between). This is done with a 1k resistor in series with a 25k pot. This allows one to change the value of the cathode on the third stage. 10k is the trainwreck value.
  • Changed the .002 coupling cap to .0047uf. This reduced the trebleness of the amp (it was a bit on the treble side)
  • After having played with the 12ax7 / ECL86 version, I converted it to a 2 x 12ax7, 1xel84. The ECL86 tubes are getting harder to get by.
You can see the schematic here


Activity Status # hours
Design Completed 0.5
Layout Completed 2
Building board Completed 3
Drilling chassis Completed! (YES, $#%@#%^%#) 4
Installing board in chassis Completed! 3
Debugging hum Completed 15!

It is finally finished! After making a stupid, stupid mistake (shorting the input jack!) it finally made some noise. I didn't have time to play it more than 5 minutes, so, no final say on the tone yet. More play time is required (I will post clips ASAP). As with all Trainwreck amps, this amp will have a woman's name. Once it is completed and has a proper cabinet it will be called Sophie.

Some Pictures

Bare board

Populated board

View from the top

Obligatory amp porn :)

Sound clips

Two sounds clips very quickly recorded

First Clip: Clean fender-like
Second Clip: Trainwreckish

Last Updated ( Friday, 23 February 2007 )