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Dallas Scala !960s Tube Guitar Amplifier Gets Some Mods



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Part two of this Dalls Scala Guitar Amplifier. I decided to do some mods to this guitar amp. The tone control was dreadful and the amp just didn't good at all.
The Mods
Remove one jacksocket.
Added a 47K grid stopper on the 1st stage
Moved volume one to work between the gain stages of the 12AX7
Added a 5F2A tone control
Turned volume 2 in to a master volume
Changed the output tube to 6P18P
Added a cathode bypass switch on stage 2: 470nf
The switch was fitted in the empty jack socket hole.
Changed the dropping resistor to the screen from 3.9K to 4.7k
Changed the dropping resistor to the plates of the 12AX7 from 47K to 2.2K
Added a 1K screen resistor on the output tube
Added a 100K grid stopper on the grid of the second stage
Added a fuse on the HT 250ma
Put a 1amp fuse in the plug.
The amp is biased at 10.2 watts
bias resistor now 300R 5watt
Category
Audio
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