Announcement

Collapse
No announcement yet.

Missing input resistors on 5E3

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Missing input resistors on 5E3

    I picked up a 5E3 build but it has a gain issue: even with the amp volume all the way down, the amp distorts way too early. There's no clean headroom and at any volume above headphone levels the amp goes into a harsh blatting distortion. I haven't done a lot of troubleshooting yet but 2 things jump out at me: The 68K input resistors between the input and the first preamp tube are missing, and the builder used a big 5 watt wirewound resistor for the 5K between the first and second filter caps. I'm guessing the 68K's need to be there, not sure about the wirewound.

  • #2
    That 5W wirewound probably won't cause a problem. The 68Ks will take a little of the edge off but overall not make a huge difference. You may not even notice. The one nice thing the 68Ks give you is the option of the #2 input. If you are using a 12AX7 as the first tube, you won't have much headroom. The amp will distort before the Volume control is past 2. There could be other issues in the amp. A check of the voltages on the tube pins usually reveals the problem.
    WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
    REMEMBER: Everybody knows that smokin' ain't allowed in school !

    Comment

    Working...
    X