FILTER CAPS QUESTION

Discussion in 'The Workbench' started by Marcomel79, Nov 4, 2021.

  1. Marcomel79

    Marcomel79 Well-Known Member

    Joined:
    May 3, 2021
    Messages:
    579
    Likes Received:
    719
    Location:
    Oslo
    So i have a tube town 18W plexi clone and it comes stock with two 100+100mF filter capacitors. Im new to building amps and i still have everything to learn.. ive heard that the higher the value, the stiffer and fiercer the tone. Can i just go ahead and switch to 50+50mF to see if i like it better or do i need to change anything in the circuit? Ill attach a schematic of the amp. Here it is
    CEC7C5B4-F38E-4EF4-87F7-2BDEC0BB8E20.jpeg C7FD4922-A622-40D6-A99A-DB90B05A8A90.jpeg
     
  2. South Park

    South Park Well-Known Member

    Joined:
    Sep 14, 2019
    Messages:
    3,822
    Likes Received:
    3,552
    I don’t think it will make any difference . Not enough power draw to get any real voltage sag . It can be done you can install a choke and leave the filter caps the same
     
    Marcomel79 likes this.
  3. william vogel

    william vogel Well-Known Member Gold Supporting Member

    Joined:
    Dec 18, 2016
    Messages:
    748
    Likes Received:
    872
    I’d use 32uF + 32uF cans myself.
     
    Marcomel79 likes this.
  4. Pete Farrington

    Pete Farrington Well-Known Member

    Joined:
    Jan 18, 2021
    Messages:
    893
    Likes Received:
    893
    Location:
    Staffordshire UK
    I think that with that power amp and its 8k OT, you’d need to reduce to the reservoir and g2 HT node caps perhaps as low as 22 or 16uF before much of a difference became apparent.
    Be aware you’d need to crank the volume to hear it - the power amp needs to suck up lots of current for the HT to sag.
     
    Last edited: Nov 4, 2021
    Marcomel79 likes this.
  5. Marcomel79

    Marcomel79 Well-Known Member

    Joined:
    May 3, 2021
    Messages:
    579
    Likes Received:
    719
    Location:
    Oslo
    Thank you @Pete Farrington and @william vogel. Is there a predictable change in tone by lowering the FCs value or is the change only in the feel of the amp? I apologise if it is a stupid question
     
  6. Pete Farrington

    Pete Farrington Well-Known Member

    Joined:
    Jan 18, 2021
    Messages:
    893
    Likes Received:
    893
    Location:
    Staffordshire UK
    Perhaps the tone changes micro second to micro seconds as the ADSR of a cranked note progresses, but if so, it’s beyond me.
    Overall, the momentary HT voltage reduces a bit, so the perceived tonal attack and biteyness may seem to reduce too.
    But it’s more of a feel / dynamics thing for me.
     
    neikeel, XTRXTR and Marcomel79 like this.
  7. william vogel

    william vogel Well-Known Member Gold Supporting Member

    Joined:
    Dec 18, 2016
    Messages:
    748
    Likes Received:
    872
    This ^^^
     
    Marcomel79 likes this.

Share This Page