How Do I Fix Amps!!

Discussion in 'Amps and Cabs' started by aram, Jan 31, 2008.


  1. aram

    aram Member

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    Soooooo.

    I just had my 3 fenders worked on, new tubes, caps and a new speaker in my SFDR. The total came to $450.

    While I don't think this is unreasonable, it also made me think,

    "Damn, I need to learn how to do basic amp servicing."

    Are there any good books or DVDs out there that are helpful?

    All my amps are old fenders, PTP, so I can't imaging it being too hard.

    Would be great to be able to change my tubes without blowing $150.

    !!!

    Thanks!

    aram
     
  2. aram

    aram Member

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    anyone? anyone?

    :roll
     
  3. striven82

    striven82 Member

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    Changing tubes is like changing your socks. Pull one out, put a new one in. Biasing is a different story. But, with basic tools, it's a breeze.
     
  4. 2x6L6

    2x6L6 Supporting Member

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    Pros may disagree, but a few years ago I learned a ton from the Gerald Weber videos. I had read a lot and had a general idea about what to do/not do, but there is nothing like seeing it for yourself. Those videos are a great way to become introduced to basic Fender amp servicing. Weber's book "A Desktop Reference to Hip Vintage Guitar Amps" is a pain in the ass because it's so poorly organized but I also gleaned a lot from it. I have Dave Funk's "Tube Amp Workbook" that's also pretty cool. Another oft-criticized tome is Pittman's Tube Amp Book, which again, I pulled a few things out of.

    I hear Torres' book is a good one, and I think there are a few others as well. Of course the web has about as much info about servicing amps, especially Fenders, as any book. The Fender Forum has some great techs there who share readily. Use the search function. Same here, on TGP.

    Between my minimal dangerous knowledge (tube amps CAN kill you!) and that of forum friends who help out, I can't imagine ever taking any of my amps into a tech again. Same goes with buying beaters and bringing 'em back to life. Totally do-able. Take the plunge, it's fun as heck to work on these things.
     
  5. Gordon

    Gordon Silver Supporting Member

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    Yes, the Dan Torres book is quite good for a guitarist who's intent is to service his own amp. It gives you what you need to know and not a lot of "unnecessary facts".
     
  6. StompBoxBlues

    StompBoxBlues Member

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    I think most of the books out there on amp and guitar service....could have used a proffessional technical editor going over them.

    I mean, a lot of them, as was mentioned, poorly organized, not geared to the stated audience (if you write a technical book geared to the newby, need lots of explanations, etc., if geared to the pro, then just the necessary...many of these books seem to go one way then the other) and most of all INDEX it. My GOD...with any decent word processor they can generate indexes (I know it is really indices...but..) at the flick of a switch. The more the better.

    Also, ways to be sure which system or type you are working on.​
     
  7. aram

    aram Member

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    thanks everyone!

    I think I'll get the torres book.

    I play silverface and blackface fender amps, so I know that these are considered the easiest t service.

    I just don't want to kill myself!!!!!!
     
  8. aram

    aram Member

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    jeesh youtube is my friend.

    I wish I had done this posing earlier!!!
    :)
     
  9. Blue Strat

    Blue Strat Member

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    Speakers and tubes are easy. Get yourself a bias probe (eg, Bias Rite or Bias King) for biasing power tubes.

    I don't recommend going "inside" the chassis without at least watching a Gerald Weber video and reading his first book. Guys who work on amps for a living usually have some formal electronics background.

    Sure, it's easy to solder and replace components but that doesn't make you a tech. An understanding of Ohm's Law and analytical techniques are crucial to working on electronic equipment. Replacing a defective component is easy. Figuring out how it became defective is another story.

    Good luck!
     
  10. VaughnC

    VaughnC Supporting Member

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    I don't think you can jump right into repairing amps without an understanding of the fundamentals of electronics, the math behind it, and an understanding of basic test equipment. Theres a reason why my electronics degree took a few years to acquire.

    I'd start by taking some formal basic electronics courses.
     
  11. scottl

    scottl Member

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    Hi Aram! Just beware, working on and/or modding/tweaking amps can be fun! I was well on my way mastering triadic superimpositions (lol) and then I got sidetracked with amp tinkering... It can be damaging to your playing! Now my motto is: less soldering, more playing!
     
  12. Unabender

    Unabender Member

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    Oh the wonderful self dilusion of saving money through tinkering your own amps :) I remember it well.

    The truth is you will spend MUCH more money on your amps IF you
    do it yourself, because this stuff just takes a lot of time. You could easily earn the 450$ much quicker. Not to mention you can damage the amp while learning stuff and degrade it's value.

    So no, you will probably not save money. But you might gain a great hobby, which is something money cannot buy. It's just plain fun... and very addictive.
     
  13. fenderpro

    fenderpro Member

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    aram
    if you're worried about killing yourself, whatever else you do, while you are working on the amp, UNPLUG IT! as someone who didnt do that once, i cant stress that simple thing enough.
     
  14. 2x6L6

    2x6L6 Supporting Member

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    Ohm's Law and analytical techniques? Great idea, especially if you are going to get into diagnosing serious problems, or if you want a deeper understanding of the underlying "how" and "why" of your amps. Do NOT let anyone discourage you by saying you need to take a formal class before you get into this (obviously the more you know, the better, but you can do this without electronics classes). Plenty of the best techs out there never did. Gazillions of us hobbyists learn as we need the knowledge. Fun, addictive, satisfying. Totally do-able.

    Good advice above re: tools. All mine fit in one tool box (no shop here - I do this work in my house). One tool I wish I had built a long time ago is a cheesy version of the DLS amp cradle that I slapped together last year:

    [​IMG]

    Nowhere near as cool as the real deal, but works fine.

    Oh, and btw as you'll probably read right off - unplugging the amp is a pretty good idea, but even an unplugged amp stores enough juice to stop your heart. Drain the caps!
     
  15. StompBoxBlues

    StompBoxBlues Member

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    While I agree, this could imply that with the plug out it is safe. That is not the case, the large capacitors (and unless you can read a schematic and know theory you don't know WHERE that voltage appears in the amp) store enough to severely shock or possibly kill. Even if you know how to discharge them, they can build up charge again.

    Also totally agree with VaughnC, that a basic understanding of electronics, and how to use test equipment (for example and ammeter is inserted into the path and the leads need to be in the right sockets on the meter, voltmeter measures parallel across...how to read them correctly, scale, etc..)

    I agree, it is a lot of fun, I have an ASEE in electronics, and I am aware of how much I either forgot, or haven't learned well enough, I've done some modest mods on a few amps, set bias, but am VERY careful almost to the point of paranoid...a simple misunderstanding can have very unpleasant consequences. I have to think...and I have worked on electronics for year (just not tubes until a while back)...
     
  16. rockon1

    rockon1 Member

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    In the past year Ive learned how to bias my amps both cathode and fixed,properly drain the caps to work on them,minor repairs (fixed the PCB mounted input jack on my sons VC50)and even fix blunders along the way! Just replaced two resistors in my SS I inadvertantly burned while biasing today! Needed help being pointed in the right direction(thanks JP!) but with the schematic and Radio shack I managed quite well actually! Now I feel fairly comfortable with replacing componants on a PCB. Had no idea what a desoldering gun was until today. Its a start. Bob

    [​IMG]
     
  17. Gene

    Gene Member

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    Hi Aram,

    You are kidding, right? I spent $150 on 1 tube.... I bought the 66 pro reverb for 300 bucks. Where is the sanity?
     
  18. Mickey Shane

    Mickey Shane Supporting Member

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    +1

    The confidence, that knowing what you are doing will give you is priceless.

    Interestingly enough, it was amp electronics that gave me a desire to purse an electronics degree.
     
  19. rockon1

    rockon1 Member

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    Yep. I work on automatic transmissions for a living. A parts replacer is just that. A good rebuilder knows why a tranny went bad before that transmission is reassembled. That said Im pleased with my parts replacement today. I learned some valuable soldering skills at least. Bob
     
  20. soldano16

    soldano16 Member

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    It's worse than that. Even unplugged, some capacitors may still hold enough juice to kill you. They have to be bled off before you can touch them.

    EXPERTS - correect me if I'm wrong.

    Don't take foolish chances. Know exactly what you are doing before you do things.
     

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