Results 1 to 10 of 10

Thread: My champ may be ailing

  1. #1
    Forum Member DanTheBluesMan's Avatar
    Join Date
    Nov 2002
    Location
    Southern NH
    Posts
    4,484

    My champ may be ailing

    Last week, I plugged my Champ into the 4 ohm mono jack of my 1960A cab. It sounded glorious.

    Until I started using my volume pots on my Les Paul Deluxe. Scratchy the full range of motion, both volumes. I tried another guitar, also less than a year old. Same thing. Scratchy the full range of motion.

    I mentioned this and got a reply from an amp builder to try another tube in the first position (preamp). He said

    This is usually caused by DC voltage on the input jack of the amp, which comes from too much grid current in the first tube. This creates a voltage drop across the grid resistance, which causes the scratchiness. Try swapping out the first preamp tube.
    what does this mean in layman's english? Different tubes, same results
    "Live and learn and flip the burns"

  2. #2
    Forum Member jrgtr42's Avatar
    Join Date
    Jan 2006
    Posts
    1,109

    Re: My champ may be ailing

    Are you sure it's not the guitar's pots that are scratchy?
    Was it scratching with those two guitars and not another?
    ********************************
    "Do you call sleeping with a guitar in your hands practicing?"
    "It is if you don't drop it."
    - Trent Lane, Daria, Episode 1-2.

  3. #3
    Forum Member DanTheBluesMan's Avatar
    Join Date
    Nov 2002
    Location
    Southern NH
    Posts
    4,484

    Re: My champ may be ailing

    Quote Originally Posted by jrgtr42 View Post
    Are you sure it's not the guitar's pots that are scratchy?
    Was it scratching with those two guitars and not another?
    pretty sure. The volume of the scratchiness did not change and it was the entire length of the wiper motion, I've never heard any potentiometer do that before, and it was only that amp. It didn't do it on the Princeton Reverb with either guitar.
    "Live and learn and flip the burns"

  4. #4
    Forum Member Don's Avatar
    Join Date
    Jul 2002
    Location
    Massachusetts
    Posts
    11,099

    Re: My champ may be ailing

    Try a different preamp tube and see if it helps.

  5. #5
    Forum Member DanTheBluesMan's Avatar
    Join Date
    Nov 2002
    Location
    Southern NH
    Posts
    4,484

    Re: My champ may be ailing

    Quote Originally Posted by Don View Post
    Try a different preamp tube and see if it helps.
    I did, same results
    "Live and learn and flip the burns"

  6. #6
    Forum Member phantomman's Avatar
    Join Date
    Aug 2007
    Location
    Ten miles from the Mexican Frontier, in Arizona
    Posts
    6,516

    Re: My champ may be ailing

    My guess would be one of the cathode-bypass caps for either the V1A or V1B stage (or both of them) have exceeded their useful service lives OR the coupling cap between V1B and the V2 power tube has succumbed to geriatric-related failure.
    "When injustice becomes law then rebellion becomes duty."

  7. #7
    Forum Member DanTheBluesMan's Avatar
    Join Date
    Nov 2002
    Location
    Southern NH
    Posts
    4,484

    Re: My champ may be ailing

    Quote Originally Posted by phantomman View Post
    My guess would be one of the cathode-bypass caps for either the V1A or V1B stage (or both of them) have exceeded their useful service lives OR the coupling cap between V1B and the V2 power tube has succumbed to geriatric-related failure.
    I did buy the amp 15 years ago and who knows when it was last serviced. I shall have to see if I can find an amp tech in the area. I used to know a guy up in Manchester (20 miles away), whom although somewhat eccentric, probably a shock too many , who was quite good.
    "Live and learn and flip the burns"

  8. #8
    Forum Member DanTheBluesMan's Avatar
    Join Date
    Nov 2002
    Location
    Southern NH
    Posts
    4,484

    Re: My champ may be ailing

    welp, looks like he's no longer amongst the living, at least in NH

    sure AF ain't taking it to Guitar Center. As much as I'd like to tinker with stuff, I don't have anybody to watch do this and learn from so I'm inclined to not do it myself.
    "Live and learn and flip the burns"

  9. #9
    Forum Member Don's Avatar
    Join Date
    Jul 2002
    Location
    Massachusetts
    Posts
    11,099

    Re: My champ may be ailing

    I wish you were closer! I do this kind of work and would be glad to take a look at it for you.

  10. #10
    Forum Member jrgtr42's Avatar
    Join Date
    Jan 2006
    Posts
    1,109

    Re: My champ may be ailing

    Quote Originally Posted by DanTheBluesMan View Post
    I did buy the amp 15 years ago and who knows when it was last serviced. I shall have to see if I can find an amp tech in the area. I used to know a guy up in Manchester (20 miles away), whom although somewhat eccentric, probably a shock too many , who was quite good.
    I haven't run across many amp tech's who WEREN'T eccentric. My theory is too sniffing too much solder fumes...
    but I knew a guy near-ish me, in Milford, MA, who, while very good, was as so far out there he was almost back in.
    If ya happen to run across someone in the Lowell Ma or south area, let me know... My VibroChamp needs some lovin'.
    ********************************
    "Do you call sleeping with a guitar in your hands practicing?"
    "It is if you don't drop it."
    - Trent Lane, Daria, Episode 1-2.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •