120Hz Hum without Tubes inserted

Discussion in 'The Workbench' started by marshmallow, Jan 9, 2012.

  1. Michael1987xl

    Michael1987xl New Member

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    This is some of the most amazing bullshit it has ever been my displeasure to have to sit through. Marshamallow, I don't know you, I don't know where you're from or who firmly lodged the rocks into that otherwise apparently thick and empty skull of yours. What I do know is that you have done the impossible. You have soured a guy who couldn't be soured. That is some fucking achievement. That took real brass, man.... between your ears.

    And just you know where this is coming from, yes, I've known Lane for a fair while now, not just professionally but socially and consider him among my friends. I know other people who know him also and to a person every single one of them has the same opinion of the guy: unflappable, mild mannered, generous (to a fault, now it seems) and about as smooth, tenacious and smart as they come.

    Unlike me, with probably a bit more attitude than I should have and a hair trigger temper, Lane just doesn't snap at people, dig his heels in or have a problem admitting his mistakes. Everything with him is take a step, analyze, go back if you have to. If he was half as unreasonable as your tiny mind is trying to play up here, he wouldn't be as nearly as respected as he is or very good at his fucking job. Since he is both very well respected and excellent at his job, guess who's the jerk here?

    Right. It's you.

    Let me tell you guys something; there's some serious bullshit going around this place lately and this is just the latest symptom. The moderators seem to have some half-assed "free speech" concerns about it; that's their problem. I've moderated forums before, too, there's a way to do it without being a censor and this ain't it. I'd match my knowledge of that subject against any moderator here and believe me, if their idea of "freedom of expression" is allowing ignorant and often prejudiced, judgmental assholes to dominate the conversations and run people off, they don't stand a chance against what I know about it. This isn't the first time that some really talented, good natured and intelligent people who have real contributions to make have had genuine cause to feel insulted, under appreciated by the ignorant, mean spirited, self-aggrandizing crap around here and be justified in telling the whole group to go fuck itself. And yeah, the moderators know what the fuck I'm talking about whether they ultimately choose to continue playing stupid notwithstanding. If that's what this place is about, who gives a shit? Frankly, you can have it.

    As for you, Marsha - mallow, you've made it exceedingly clear that you're just another ill mannered knot head in over his questionable brains on a project you likely had no business getting involved in in the first place; embrace the horror. The fact that you're lacking in brains and talent isn't your fault; perhaps you should go kick your parents for that. That you chose to be a douche bag about your ignorance and an ingrate on top of it is very much your fault. Well played. And before anybody starts in about how this kind of noise about something as ubiquitous as an amplifier repair is a bit over the top, let's get this much straight right here, right now; This is about you being an ass.

    For insulting my friend, though, when he gave you a lot of his time, talent and input for NOTHING and being a prime reason of why he's sick of this place, you earn a very big Fuck You.

    Congratulations. We're all very, very impressed. I'm sure the rest of the world is, too.
     
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  2. Buggs.Crosby

    Buggs.Crosby New Member

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    Nice Job by the OP....what an Asshole you must be....it's hard to piss off Lane but seems that you have....take note my 1st posts in months is at the defense of a well educated and well respected Tech.....To Alex and Adwex....Nice forum you have here with all the knowledgeable members leaving in droves....how Lane made it for so long is beyond words.....Your Fucked up Romper Room of a Forum does not deserves the likes of Lane and the other techs that have left.....cant wait to see all the bad info that gets posted in the future......Have fun Kiddies because your place Sucks!
     
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  3. MajorNut1967

    MajorNut1967 New Member

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    Marshmallow,

    I have a few questions for you, "how did you arrive at the 120 Hz note coming out of your speaker?” Are you using a frequency counter to actually know what the cycles per second are? And by the way what country are you in, the US? Your inexperience is kind of showing because you're looking everywhere except the obvious of where the problem is. First of all the transformers on that amplifier are way too close to each other and second of all there not arranged so that the eddy current fields are opposed. I've seen some of the fairly knowledgeable guys give you some input in the right direction. For some reason you do not understand the physics involved in induction and that if you have a loose core in a transformer or if you have an anomaly in the plates that it can induce a physical oscillation of a mechanical nature in an adjacent transformer! It should be clear to you that if the output section is null; all in other words the power tubes and the secondary of the power transformer are removed from the circuit and you're still receiving whatever note you are hearing through the speakers, that it is mechanical induction.

    The other part is that you asked the competent people here for assistance and then turn around and refute everything they say. This is one reason this form has gone to absolute crap and that you don't have the real technicians contributing anymore to this forum. Guy’s like Joey, Paolo and especially Lane have been big contributors to this forum and with competent knowledge and expertise, "for free”! And then someone like you comes along and starts chirping as if you are extremely knowledgeable, "well indeed if you are that knowledgeable why are you even over here asking questions!" I have a suggestion for you, why don't you take a quarter inch brass plate and put it between the two transformers and see what happens.

    Major
     
  4. MajorNut1967

    MajorNut1967 New Member

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    Well said Mate, "Hats off"

    Major
     
  5. MajorNut1967

    MajorNut1967 New Member

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    Re: [Shocking Update] 120Hz Hum without Tubes inserted


    Were you referring to me mate?
     
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  6. Buggs.Crosby

    Buggs.Crosby New Member

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    Birds of a feather spray shit together Bro....miss chatting with you
     
  7. marshmallow

    marshmallow New Member

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    It is understandable that when a tech put his experience and expertise on the line to lead the bet on a horse and thinks it's a sure win, when that horse looses it is not the outcome he expected and that won't make him feel good. Then again you have to stand by your words, so you got it wrong the first time not a huge deal. We all got it wrong. Actually that's the worst time to quit. If me I would think I can learn something new on this one. I don't blame Lane for prioritizing his time where the money is. :cool2: This is a discussion forum.

    There are good people on this forum and on this thread like anywhere else. I think they know who they are. And just like anywhere else there will be weak idle haters who reflect their personality by dwelling on the negative side of things spewing long winded laughable self indulging hate post at the first benign occasion. I literally stop reading any of these after one line. It is just not worth my time. You usually did not hear them in the constructive part of the thread but they are the first to use expletives. They too will recognize themselves. Just to be practical I don't have that kind of time to waste on that stuff.

    The 120Hz hum frequency is evident from the scope waveform measured from the voltage accross the speaker.

    Cylon I am glad you fixed your hum by replacing a tube. Hold tight to your 6100 :thumb: it is da bomb ! My amp hum is from electromagnetic induction though. But i think we will eventually find a more detailed explanation for it.

    Txloito I think I speak for all it's tough luck that you bought a new PT for squat. Still it could be an upgrade. Maybe your hum level is acceptable, but mine isn't.

    Mickeydg I agree with your summary of where we stand. It sure is a tough nut to crack. You might be on to something : according to Merren Audio In the US, harmonics in the AC mains are not well regulated nor enforced as they are in parts of europe. They have an interesting page about main power quality here:

    Merren Audio - Power Quality

    I did look at the main supply waveforms with my scope and i recall they were not quite the sinusoid looking waveform i expected. This might be part of the problem..

    Even order harmonics exist in half-wave converters. But beside the fact that we don't have a half wave AC-DC converter in this amp in my hum experiment the PT secondary is entirely disconnected (no rectification current flowing) and the OT primary is also entirely disconnected. Somehow the OT is very susceptible to the PT field. I wonder if this is an OT wear indication. An unsymmetrical hysteresis from a worn laminated core would also create 2nd order harms. Or could it be that the isolation between the laminated cores in the OT is leaking due to excessive wear ? Bottomline my suspicion has now shifted to the OT. Please note that the OT has no mechanical vibrations but the PT does. Txloito old PT did too, his new doesn't and the hum is still there.

    I have a 6 millimeters thick 8 x 8 inches plate of steel for experimenting. I found that placing it between OT and PT the hum is lowest when the plate is closest to the OT and highest when it's closest to the PT.
     
    Last edited: Feb 5, 2012
  8. diesect20022000

    diesect20022000 In Memorandum VIP Member

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    :applause:
     
  9. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

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    I will say that I believe that I was right about the magnetic induction issue from the start. I take rejection well, and am NOT a sore loser, if that's what this is about. For example, I freely admit that I may OR may not be right about a flaw in your PT causing this issue to be worse than the average 6100. I just can't say for sure. I can't help but feel that you have completely misunderstood the reason I was a bit unnerved. HINT: It had ABSOLUTELY NOTHING to do with whether I was wrong or not - for I have been wrong before, and will be again, I'm sure. It's part of being human. ;)

    -Lane
     
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  10. mickeydg5

    mickeydg5 Well-Known Member

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    Lane, where did you come from? :)

    There are plenty of amplifiers just like these two that do not have the same problem. Everyone keep that in mind.

    I don't feel that I got anything wrong. I was not finished with testing and I would not have purchased a new PT at that point. Txoloito decided to buy a new PT. I backed off to see what was going to happen. I still do not know anything about Txolioto's location (in Europe) or power supply setup. His case can still be different from anyone elses.

    You can pot both transformers but would be taking it too far for a musical amplifier. And, that still may not rid all the hum.

    A new transformer can be damaged or bad just like any other part you buy.

    There has been a lot of post and comments no one can keep straight who did or said exactly what without taking notes. Did Txoloito disconnect everything like Marshmallow? Does anyone know if Txoloito's amp has any other wiring problems like transformer taps or selector swithches connected wrong. It can happen and we cannot see it. The same goes for his house wiring and anything between that and his PT. Did or does he have other amplifiers when connected to the same source that do or do not produce the same noise? Lots of other questions need to be answered.

    I am still listening.
     
  11. Lane Sparber

    Lane Sparber Well-Known Member VIP Member

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    Just back to clarify my position. :)

    :cheers:

    -Lane
     
  12. mickeydg5

    mickeydg5 Well-Known Member

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    I hear you. I hear everyone for that matter.
    We are all here in the dark working with a flashlight sort of speak. A technician on a bench can see, prode and test to eliminate concerns at will. This process does not work so easily. So down talking or pointing fingers is of no use.

    Sometimes I may not be tactful and may come across wrong. I hope people just tell me so I can correct myself. World Peace.
     
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  13. txoloito

    txoloito New Member

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    Hi mickeydg5:

    1.- I`m from spain, concretely from Vasque Country.
    2.- I disconnect everything like Marshmallow. I put images in anterior posts.
    3.- The amp hasn´t got anything more wrong. It´s a second hand amp, and when I bought it already had that noise and i revised all, and changed all electrolitic capacitors, and all components that didn´t look in good condition, but the noise was still there.
    4.- I have proved it, in different locations (house, pubs, rehearsal rooms, etc...) and the noise is the same in the all locations.
    5.- In a lot of cases, the only thing that was conected to the source was my amp.

    Regards
     
  14. mickeydg5

    mickeydg5 Well-Known Member

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    Txoloito
    Sorry, I did not notice that you had said Spain before.
    I have read through the thread again and took note of your noise assessment of these amplifiers on youtube videos. Design fault maybe, had to think about that???
    I looked at your diagrams and pictures.
    Well then, that makes it tougher. How do other valve amplifiers react when plugged into the same places? I may have more after you anwser this.
     
    Last edited: Feb 6, 2012
  15. txoloito

    txoloito New Member

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    The other amps are very quiet compared with mine, I tried VHT, Mesa Boogie, Peavey, Carvin and none has a similar noise.
     
  16. mickeydg5

    mickeydg5 Well-Known Member

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    So it seems that the hum is related to this ampifier design and not the power source.
    Is your amp still apart? Your pictures only showed the PT removed. Is everything else still attached to the chassis?
     
  17. CaptainZero

    CaptainZero Well-Known Member

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    So Marshmallow, did you replace the PT? Just from the other posts (I'm not a tech, but like to read these to try to learn something) There have been other fixes, like replacing tubes, that may work for you even though they didn't work for someone else. It's a $100 to rule that out, and after all the work you've done on this I sure as hell wouldn't start looking at other stuff until I ruled out the items the experts (who are thankfully still) around here have told you.
     
  18. txoloito

    txoloito New Member

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    mickeydg5 -> I have all attached to the chassis. At this moment the unique element that is not attached, is the OT, because I am testing the diferent positions with it.

    CaptainZero -> We have explained above that the noise continues even when the amplifier is in standby mode and without tubes.

    When I had a free time, I will take a video to show you the noise, and how it change with the OT position.
     
  19. mickeydg5

    mickeydg5 Well-Known Member

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    I would like to see video. Get some overall and close up shots.
     
  20. mickeydg5

    mickeydg5 Well-Known Member

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    marshmallow
    I know the back and forth comments have been agitating, putting that aside, your input can be helpful.
    Same for you, what is the state of your amplifier, still apart?
    Some overall and close up pictures would be nice.

    I would like to figure this one out.
     

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