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***Solved***60 Cycle hum from Traynor YBA-300. I have tried everything.

Discussion in 'Amps and Cabs [BG]' started by FunkHead, Jul 4, 2020.


  1. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    I am looking for help diagnosing a hum from my favorite amp of all time.

    I am going to list all the facts and hope you will read them so we stay on track.

    1: Hum is 60 Cycle (Hz). I verified this with a tone generator.

    2: Hum is present without bass plugged in.

    3: plugging bass into effects return eliminates hum 99%

    4: Hum is controlled by volume knob. It's there from about 2 and gets louder as you increase volume.

    5: I have eliminated tubes as the cause by swapping each and every tube.

    6: there are times where the amp is dead silent and then the hum comes back.
    >This leads me to think it's an internal connection or something from my home wiring.

    7: I have pulled and inspected each and every circuit board and there are no bad solder joints visible.

    8: Amp has only about 40 hours play time. but I have had it for 8 years or so. I always make sure to play it every few months or so. I think the longest it went un-played was 6 months.

    Please give ideas on what I could possibly look for inside. I can add jumpers to grounds if that could possibly be the cause but all ground lugs are tight.
     
  2. abarson

    abarson

    Nov 6, 2003
    Santa Cruz
    Time for a real tech to go over it.
     
    BassmanPaul and InhumanResource like this.
  3. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Unfortunately that's not an option right now. Nobody remotely close is open.
     
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Then your best bet is waiting for a REAL, QUALIFIED tech.

    Everything else is just a wild ass guess, something that's just as likely to cause additional problems.
     
  5. abarson

    abarson

    Nov 6, 2003
    Santa Cruz
    And you run the risk of getting electrocuted as big tube amps have very high voltages in them. Just looked at the schematics and it's not a simple amp by any measure.
     
    BassmanPaul and agedhorse like this.
  6. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    The thing is that it will go away and then come back. would a bad ground cause that? Would a bad component cause that? I don't mind getting a real tech involved but I was under the impression that bad grounds were the most common cause so I would like to at least eliminate that as the cause.
    I would honestly like to hear any guesses possible.
     
  7. JKos

    JKos Supporting Member

    Oct 26, 2010
    Torrance, CA
    At least Traynor is nice enough to openly supply schematics. And, your symptoms help narrow it down to the preamp. A good tech can make quick work of it.

    - John
     
  8. byacey

    byacey

    May 16, 2008
    Alberta, Canada
    Being that it disappears when the volume control is set to zero indicates it's getting into the signal path in the first preamp stage. Right off the input jacks they show a ground wire in bold with a screw eyelet to be fastened to the chassis with a machine screw; you might want to check that it is tight. Anything beyond that, get it to a real certified tech.
     
  9. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    There are so many possible causes that I couldn't even give you an honest guess.
     
  10. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    I appreciate what you are saying. There is one thing about this design that makes we wonder though.

    The input is a small PCB with a metal shield sort of isolating it from the rest of the components. From there, there's a very thin connector to the Pre-amp. I was thinking that this could be picking up interference. If I get my hand anywhere near this area the hum is affected. It's like an electro-magnetic field in that location.

    I guess what I was hoping to figure out mostly is if a component could be intermittent or if it would be more of a connection issue.

    Also could bad home wiring cause it?

    Can ground loops occur inside a head?
     
  11. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Just tried a completely different outlet in another room. Noise is now gone. The outlet is a GFI so I don't know if that has anything to do with it. I won't mark this thread as solved just yet but she's nice and quiet at the moment.
     
    wave rider and Max Bogosity like this.
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    It's possible that the GFI protected receptacle does not have a protective ground (even though there is a ground terminal present). While this can be legal, there MUST be a label stating that there is no ground present.

    If the noise increases when you hand gets close to the jack (with nothing plugged in), it just indicates that the jack does not self-terminate. I don't know if this is normal for this amp, but a QUALIFIED, EXPERIENCED tech would be able to determine this.

    The size of the wire means nothing.
     
    FunkHead, BassmanPaul and byacey like this.
  13. InhumanResource

    InhumanResource

    Dec 28, 2012
    Let's start with replacing all the knobs and the output transformer
     
    dkelley, dbase and agedhorse like this.
  14. HardNHeavy

    HardNHeavy

    Apr 17, 2014
    PA

    i was just gonna say if you tried a different outlet...good deal for now...i use a vintage traynor ts-120b love it!
     
    FunkHead likes this.
  15. HG1180

    HG1180

    Aug 11, 2019
    Millsboro,DE
    Check the continuity between the ground prong on the power cable and the power input on the amp.

    If its not that, wait for someone qualified to take a look at it.

    The main reason I say it may be grounding is because you said it disappears when you plug into your effects, which have to be grounded in order for them to produce a clean signal.

    Good luck!
     
    FunkHead likes this.
  16. byacey

    byacey

    May 16, 2008
    Alberta, Canada
    That, or the input jack is floating due to a broken ground connection.
     
  17. Nah! It's gotta be the caps!! :hyper:
     
  18. Killing Floor

    Killing Floor Supporting Member

    Feb 7, 2020
    Austin, TX
    Your OP says you have tried everything. Really? Did you try the most obvious solution?
    New Amp Day!
     
  19. Killing Floor

    Killing Floor Supporting Member

    Feb 7, 2020
    Austin, TX
    @agedhorse back me up on this one. Did you check all the tubes, do they still look Blue inside? Once the blue smoke leaks out they don't work anymore. That mmmm good model train smell is the rock'n'roll train leaving the station.
     
    Mingo Sanders likes this.
  20. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Thanks for you input:). I really doubt any other amp would quite cut it after owning this one. Maybe an AD200 MK3 but I will stick with this one for now.
     

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