Tuesday, November 4, 2008

4 watter high gain tube





high gain 4.5 watt using 2x 12ax7 and a single ended el84
secondary voltage 240--ct--240 which produce about ~290 after rectify. 3.15--ct--3.15 2.5A for the heater. not really loud ,can play in house but will scream if attached to 4x12 celestion or higher sensitivity speaker.. design to distort at low level due to high gian preamp.
enjoy the clips!

Thursday, October 30, 2008

5150 EVH







5150 with no power supply came in , its a 120V wallvolt series.. 5 preamp tubes, 4x6l6gc..



,

Tuesday, October 28, 2008

marshall JMP 100watter



old input jack


new input jack relpaced due to old part got leaking (ground)
stabalizing the bias section..
new chatode caps and dc blocking caps.



overall view
marshall jmp 100 at studio shop space suddenly got problem noise due to grounding issue.take about a week to debug and replace new part.

Sunday, July 6, 2008

Friday, July 4, 2008

twin reverb (2)



bias resistor change from 33k to 22k to increase the bias, bias hotter to achive better tone IMO..
increase the bias by reducing negative supply to grid(pin 5) from -40v to about -35v..



plate voltage (pin 3) - 460 v (all 4 tubes)
S.grid voltage (pin4)- 450v (all 4 tubes)
- bias ~ -35v
change all coupling caps for preamp and trem chatode ,change all filter caps due to old one already burst out...