Amp Maintenance DIY

Discussion in 'Amps and Cabs [BG]' started by Jibudo, Jun 9, 2021.

  1. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    I'm qualified to do it, but have had remarkably few amp problems requiring service. And I wouldn't know where to begin with the modern stuff unless it's something easy like a broken switch. I've fixed basses, and recently re-glued a seam on my cello. I've also fixed home appliances.

    I've repaired cables.

    I think that the lighter, smaller gear tends to get less abuse because it doesn't get knocked around as much. For instance my amp head goes into a small backpack when I'm done with a gig, and doesn't come out until the next gig. I load and transport all of my gear myself. So it lives a pretty cushy life.
    MAXSPINRUN and agedhorse like this.
  2. Yes yes, but how do you drain, filter, and replace the magic smoke? Or is that a sealed chassis?
    Rich Fiscus, fig and agedhorse like this.
  3. larrysb


    Mar 23, 2020
    $ilicon Valley
    Well, as a electronics engineer, who worked through high school and college as an electronics technician in a variety of industries, including musical equipment, yes, I maintain my own equipment.

    Solid state bass amps need little care, other than cleaning the dust out and cleaning the controls and jacks every so often. Mostly, if it ain't broke, don't fix it.

    Tube gear is a bit different and needs more ongoing care. But, be aware, they do have lethal voltages inside. An SVT or a 400-PS can deal you a deadly (not kidding) shock.
  4. BoogieZK


    Sep 28, 2008
    Toulouse, France
    Common sense guys?
    When you wash your sensitive areas, do you use a high pressure water cleaner or 60grit sandpaper?

    Yes, do maintenance with caution and good sense.
    Soft brushes, isolated screwdrivers, a working and good voltmeter, adapted size tools.... Common sense right?
    Or is it this hard?
    Buster Brown likes this.
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    The pressure drop across a filter requires a lot more fan power for a given CFM. This can greatly increase the noise level, especially for the smaller diameter fans.

    Clearly, you don’t know anyone who works in an ER. You might be surprised at how little common sense some folks have.

    I see it sometimes in amps returned for service too, some scary looking stuff.
    roborend and MAXSPINRUN like this.
  6. JakobT


    Jan 9, 2014
    Oslo, Norway
    Yes, I dust mine every week or so. :)
    agedhorse likes this.
  7. BoogieZK


    Sep 28, 2008
    Toulouse, France
    No I do, i work in many type of industries including customers service for car maintenance products... And yeah i've seen some eyes-ripping stuff.
    Still I work in satellites and clearly gear is abused and raped every day....
    I just have some rest of hope that people who bought expensive gear and who try take care by themself of this gear will not go BAAAAZOOOOOKKAAAAA inside of it, just because!
    I mean come on.
  8. Many, many years ago, for some reason I can't remember, I attempted to adjust the bias on my Hartke AH3500. A minute turn of a relevant trim pot resulted in a trip to the nearest amp tech and a not insignificant bill; lesson learnt.
    byacey and agedhorse like this.
  9. chris_b


    Jun 2, 2007
    I switch my amps on and off. That's it. I'm a bass player not an amp guy.

    In my life I've had 2 amps fail and they went back to the repair shop. I've had no issues/problems since switching to SS and D class amps. These things are as reliable as I could wish for.
  10. Strangely in 45 years of playing, the only amp that ever failed me was Class D. The failure was nothing to do with topology, it had a fractured solder joint on an output connection.
    agedhorse likes this.
  11. dbase

    dbase Gold Supporting Member

    Jan 3, 2008
    South Jersey, USA..
    I change the pots and caps on a regular basis just for gigglies. ;)
    agedhorse likes this.
  12. 40Hz

    40Hz Supporting Member

    Other than basic cosmetic care, I otherwise leave my amps alone. And I haven’t experienced any issues other than a tube needing replacement.

    With preamp tubes I just replace them with the same tube. If a power tube or something else looks iffy, I’ll send it (along with any replacement tubes I want to use) over to my tech and let him check it out and/or handle the re-biasing should tubes need replacing. He appreciates the business. And I have more profitable uses of my time than ditzing around with circuitry I don’t fully understand.

    My background is in digital electronics and IT. If there’s an electronic or other issue with a datalink, a server, or a network switch, I’m in my home element. And I and have the tools and the know how to troubleshoot and fix it. Anything else, beyond basic electrical wiring or data cabling, I leave to other professionals. And I’ve never regretted it.
  13. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Likewise, many folks create their own unique are creative problems messing with their computers and network settings, well beyond their pay grade…
    Jason Stock likes this.
  14. 40Hz

    40Hz Supporting Member

    Occasionally. But due to the extreme modular construction of data systems which are, by design, fairly easy to troubleshoot and repair compared to many other systems since zero downtime is pretty much the industry standard for IT, there’s considerably less risk for a moderately knowledgeable amateur to open the hood compared to more monolithic audio systems.

    Software and operating systems are a different matter. But not most electronics found in data systems. You don’t encounter the varying border states (good, suboptimal, less good, even less good…etc.) you see with analog electronics. I think that, when combined with the potentially lethal current and voltages found inside many guitar amps, makes troubleshooting and repairing a guitar amp far more challenging and demanding of experience and expertise. Piking around willy-nilly inside a network switch may fry the switch. But it’s highly unlikely you’ll ever be electrocuted. Worse thing that might happen to you is losing your job if you did something exceptionally stupid and irresponsible.

    Besides, with digital there are only two states you need to deal with. On or Off. (Works or Doesn’tWork.) There’s little “art” involved in IT triage. Once you identify the symptoms, that resolves to a few areas that could cause that symptom. After that you know exactly what needs to be fixed. It’s pretty cut and dried. You can even flowchart it and walk someone with a little experience and training through it over the phone if necessary.
    Last edited: Jun 10, 2021
    agedhorse likes this.
  15. David76112


    Feb 19, 2012
    I actually did open up an old Peavey head once and sprayed out the inside with Windex. Rinsed off with water in the bath tub, let dry in the sun for a day. Put it all back together and it worked fine, after the initial first few jolts of current arched across my strings. Just kidding about the shock.
  16. For someone accredited with a degree in electronics and years of experience of working on gear it may be common sense and beyond any discussion, but this thread is directed towards those that don't have any formal training or understanding.

    Before the cover is even removed, there is a potential for damage or injury to occur due to lack of knowledge and training, no matter how much care and attention is exercised. To encourage people to do so will potentially create more damage than good, compared to leaving it alone if it's working as it should.
    agedhorse likes this.
  17. Redbrangus

    Redbrangus Supporting Member

    Nov 19, 2018
    Under The X In Texas
    It been my experience that common sense isn't all that common.
    boxerrider and agedhorse like this.
  18. As a qualified amp tech, I only do 'as required' maintenance. Cleaning dirty jacks and pots is the most common thing I have needed to do (for quite some time). If I pick up used gear, I do those steps right away. For tube amps, I check the bias (and usually set it a bit 'hot' for my tone tastes). My advice to anyone is to take your amp to a qualified tech if you have any problems.
    My friend, a guitar player with many years of experience, plays through his PA system directly. His son gave him a nice Orange combo amp, about 25 Watts for at home practice and convenience. He asked me to check out an awful noise. It turned out that he had the gain and volume cranked to max. No fault, just turn those dials to sensible settings (even for distortions). Imagine if he decided to go into his own amp?
    superblues and agedhorse like this.
  19. Liko


    Mar 30, 2007
    Only amp I've had that ever needed fixing was an old Lab Series L6. Plugged it straight into the wall, and a power surge blew a transistor. That was far beyond my ability to diagnose and fix at the time (these days the problem would be time and patience).

    Beyond that, about the only thing I do in the amp maintenance vein is clean scratchy pots and dust off panels and speaker cones.
  20. BoogieZK


    Sep 28, 2008
    Toulouse, France
    I think if the question is asked we're talking about people without formal training or understanding of electronics but who throw some interest into keeping an amp working well.
    I prefer encouraging curiosity, open-mind and pursuit of knowledge.

    Phone or go to your local electronic shop, they will answer gladly what to do and what not to do.
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

    Jun 22, 2021

Share This Page