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> Amplifier Hum
fkalich
post May 30 2015, 05:59 AM
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I am talking about tube amps here.

I have a half dozen large ones. A couple of them have a little hum, ether 60 cycle or 120 cycle. It is only noticeable at bed room levels.

Before I go on, yes, I like playing a big amp even at bed room levels. I don't like small amps. I don't like small amps, or plugging into some digital device rather than my big tube amps. My big tube amps are part of my manhood. I consider playing anything but a big tube amp analogous to going outside not wearing any pants.

Also, when people ask about this, most guys start taking about pickups and cords and noise gates and things. NO NO NO! What I am talking about has nothing to do with this. If you won't accept that, please go on to the next thread. I am talking about that background 60 cycle hum that you likely get from some tubes having capacitance, or 120 cycle hum that you likely get from filter capacitors not doing the job. Or perhaps something else picking up the capacitance. But it occurs even when no guitar or anything whatever plugged in, even with the volume turned to zero, so long as your master volume is turned up.

Any thoughts on this? I sometimes think that so long as it is not too loud, well some Amplifiers have a little hum, just the way it is. How do you feel? I have one amp still in warranty with a little of this hum, I think 120 cycle. And another I just recently purchased that also has the same hum just about. I have heard some guys say that they have never had an amp that did not have some background hum. But I have some with hardly any at all. I am trying to decide whether to complain about the one I just purchased and ask for a replacement, or if I am being too picky. I like getting what I want, but like to avoid being a jack ass when possible, even when dealing with a large merchant.

This post has been edited by fkalich: May 30 2015, 06:07 AM
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Todd Simpson
post May 30 2015, 06:34 AM
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We certainly woudn't want to impede your manhood! smile.gif What you are talking about here is your basic 60hz hum that is enough to make one want to go nuts now and again. The good news is that there are several devices just for this problem.

The most affordable is from, of course, BEHRINGER!! The "Hum Destroyer"

http://www.behringer.com/EN/Products/HD400.aspx

The next step up is the "pro" option, the HUM ELIMINATOR

http://www.ebtechaudio.com/hedes.html

hope this helps smile.gif Anyone else?


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klasaine
post May 30 2015, 03:52 PM
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Some airy hiss yes but not hum.

I too only play through tube amps though some are of the smaller variety. I have many from several eras. The oldest being from probably 1941 and the newest from 2012.
None of mine 'hum' at 60 or 120 cycles - that's a wall power thing or something in the amp (tubes, caps, trannys) affected by and related to the wall power.

It's probably just dirty power in your house/neighborhood.
Does that hum slowly 'phase' or slightly change frequency? That's TV station interference which is 59.95 HZ
Is the hum there and/or the same when you take your amps somewhere else?

This post has been edited by klasaine: May 30 2015, 03:56 PM


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Mertay
post May 30 2015, 11:14 PM
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QUOTE (klasaine @ May 30 2015, 02:52 PM) *
that's a wall power thing or something in the amp (tubes, caps, trannys) affected by and related to the wall power.

It's probably just dirty power in your house/neighborhood.


+1, power levels either slightly higher or lower than ideal can cause this.

We bought a tube amp for my friend a few months ago, at the store there was slight hum but when we tested at home (the building is brand new, probably has grounding) it was almost dead silent on bedroom levels.

Best is to ask an expert but grounding the entire home as far as I know isn't very expensive but it only works when power is higher than needed. Online regulators work best, also works when power is low too but they're expensive though come in different sizes so if only for amp again shouldn't be super expensive.

Keep in mind if you record to computer, they help eliminate noise too. Its like running on battery I think Todd once mentioned that he prefered recording with laptop battery.

This post has been edited by Mertay: May 30 2015, 11:15 PM


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Todd Simpson
post May 31 2015, 01:27 AM
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Recording direct via usb/guitar cable to the laptop running on battery was the cleanest signal I ever got smile.gif But our guy is wanting to use tube amps/manhood which requires either a LARGE battery backup or active voltage. sad.gif

QUOTE (Mertay @ May 30 2015, 06:14 PM) *
+1, power levels either slightly higher or lower than ideal can cause this.

We bought a tube amp for my friend a few months ago, at the store there was slight hum but when we tested at home (the building is brand new, probably has grounding) it was almost dead silent on bedroom levels.

Best is to ask an expert but grounding the entire home as far as I know isn't very expensive but it only works when power is higher than needed. Online regulators work best, also works when power is low too but they're expensive though come in different sizes so if only for amp again shouldn't be super expensive.

Keep in mind if you record to computer, they help eliminate noise too. Its like running on battery I think Todd once mentioned that he prefered recording with laptop battery.


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Mertay
post May 31 2015, 09:31 AM
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QUOTE (Todd Simpson @ May 31 2015, 12:27 AM) *
Recording direct via usb/guitar cable to the laptop running on battery was the cleanest signal I ever got smile.gif But our guy is wanting to use tube amps/manhood which requires either a LARGE battery backup or active voltage. sad.gif


Online regulators (I hope I'm trasnlating this right, maybe we mean the same as you mentioned active voltage) are as good as like working on battery with you laptop smile.gif

When voltage is higher it grounds it, and when low it uses its battery. The smallest ones should be enough for computers, I saw some at a big store where I went to buy a new harddisk but yeah a tube amp should need a bigger one since it consumes more energy.

I think that new tesla product was also capable of it, might be worth checking out.


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klasaine
post May 31 2015, 04:36 PM
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A lot of recording studios use 'ferrite rings' ... https://www.google.com/search?q=ferrite+bea...=ferrite+toroid
They definitely work a lot of the time to eliminate hum coming from radio stations, TV stations, power grid rely stations, the neighbor's juicer, etc.

This is another possible solution. I've had good luck with them ... http://www.tripplite.com/products/series/sid/825

This post has been edited by klasaine: May 31 2015, 04:36 PM


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Todd Simpson
post May 31 2015, 08:50 PM
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Good call! I've got one of these isobar units and they are quite handy. Kills lots of house hum smile.gif The little one is less than $50 online. I've got a power strip/rack plugged in to it for power distribution.

http://www.tripplite.com/surge-protector-i...lack~ULTRABLOK/


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QUOTE (klasaine @ May 31 2015, 11:36 AM) *
A lot of recording studios use 'ferrite rings' ... https://www.google.com/search?q=ferrite+bea...=ferrite+toroid
They definitely work a lot of the time to eliminate hum coming from radio stations, TV stations, power grid rely stations, the neighbor's juicer, etc.

This is another possible solution. I've had good luck with them ... http://www.tripplite.com/products/series/sid/825



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fkalich
post Jun 1 2015, 03:26 AM
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No, I am am talking about 120hz hum. 60hz hum would most likely be caused by a faulty tube.

Yes the house current is 60hz, at least in the US. Visually this is a sine curve with a parabolic peak and dip each cycle. The rectifier converts this so that the peaks are all on the same polarity, usually positive, so you end up with 120 peaks per second on one polarity, rather than 60 positive peaks and 60 negative dips per cycle. Thus you have 120 cycle DC current, i.e. 120 peaks on the same polarity every second. Then your filter capacitors smooth this out to avoid a 120 cycle hum. Eventually these dry out, which is why older amps often develop a hum.

Regarding my house current, as my other amplifiers do not have this issue, I think I can disregard that as the cause. The devices used to clean your house current deal with an entirely different issue than this. Those devices won't help a thing here. You cleanest power will still have hum when your amplifier's filter capacitors are not doing their job as they should.

I got this Bugera cheap because it was a return, but with manufacturers warranty. The odd thing is that the amplifier is 6 years old. I looked inside to see that the modification had been made to deal with the early Bugera's melting at the transformer interface. Saving a few bucks was not worth my house burning down. That modification had been made. Actually it looked fine inside, as Eurotubes has said, they use components that are average for amplifiers today. It is a myth that they use total junk components. But it has a little 120 cycle hum. It is a 6262, which is a Peavey clone. My 333 (also a Peavey clone) does not have this hum at all. So if I was to theorize, I expect that this thing was stored somewhere all those years, probably in a place that got too hot, and the filter capacitors dried prematurely. Or perhaps it was a demo and they did not use the standby switch as one should. Many people have no idea what the standby switch is even for. I don't know where MusiciansFriend gets all of these, but I suspect they acquire them from numerous sources. The hum is not real loud, not that big a deal, and the amplifier sounds kick ass. Really picks up pinch harmonics nicely, best amplifier I have had for that. I probably will send it back and ask for an exchange. Or perhaps I will just buy another and think about keeping this also, as I did get it pretty cheap. MusiciansFriend is unloading their old models now at half of what they used to cost, the new models have autobiasing, but I don't need that, I bias my own amplifiers. Yes there are some other advantages and options with autobiasing, but it has another big disadvantage, it is just another unnecessary thing to go bad, that when it goes bad may turn your amplifier into a big door stop.

The Bugeras are a hell of a good sounding Amplifier, you just have to send more of them back than with some other brands. And they do have a 3 year warranty. I contacted Bugera to make sure that the warranty was good, and they were good about responding. I suspect that they support their product better than some might believe.

Regarding my manhood, there is a reason I restrict myself to tube amps and some stomp pedals, and stay away from other crap, with that restriction if forces me to keep it simple, and it keeps me focused rather than distracted. We live in a world with resources unimagined a few years ago, but also we live in a world where for the most part people get lost in a world of useless nonsense and trivia because all the distractions level them snow blind. But that is another story.


QUOTE (Todd Simpson @ May 30 2015, 12:34 AM) *
We certainly woudn't want to impede your manhood! smile.gif What you are talking about here is your basic 60hz hum that is enough to make one want to go nuts now and again. The good news is that there are several devices just for this problem.

The most affordable is from, of course, BEHRINGER!! The "Hum Destroyer"

http://www.behringer.com/EN/Products/HD400.aspx

The next step up is the "pro" option, the HUM ELIMINATOR

http://www.ebtechaudio.com/hedes.html

hope this helps smile.gif Anyone else?


This post has been edited by fkalich: Jun 1 2015, 04:40 AM
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Todd Simpson
post Jun 1 2015, 05:34 AM
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My bad smile.gif 120hz it is then smile.gif I'm all for tube amps and manhood!! The good news it that between all the suggestions in this thread you should have plenty of things to try as it seems to cover most stuff that comes to mind. However, if you try all of it and none of it works, then one easy way to test to see if it's the amp, is to either take the amp to a shop and try it next to an amp just like it or, buy another one and have it delivered and see if you get the same hum and if not, send the new one back. smile.gif

P.S. we have been trying to diagnose all of this so far just by trial and guess work mostly as none of us have heard the actual amp. Post a clip of what it is you are actually talking about here and i"m guessing folks may be able to offer some pertinent thoughts wink.gif

QUOTE (fkalich @ May 31 2015, 10:26 PM) *
No, I am am talking about 120hz hum. 60hz hum would most likely be caused by a faulty tube.

Yes the house current is 60hz, at least in the US. Visually this is a sine curve with a parabolic peak and dip each cycle. The rectifierp it simple, and it keeps me focused rather than distracted. We live in a world with resources unimagined a few years ago, but also we live in a world where for the most part people get lost in a world of useless nonsense and trivia because all the distractions level them snow blind. But that is another story.


This post has been edited by Todd Simpson: Jun 1 2015, 05:36 AM


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klasaine
post Jun 1 2015, 04:39 PM
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Well, if it really is 120 hz noise then it's a filter cap but as Todd mentions, w/o actually hearing it we can't really know anything.

*120 hz is right in between Bb and B.


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Todd Simpson
post Jun 2 2015, 07:47 PM
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Good point on Bb B smile.gif (if you play a B flat and it's close to the sound of the hum, then you can probably isolate it to a filter cap as mentioned, I don't know if that will help you right away but you can at least take it to have it serviced)

Than again, I don't know why I didn't say that outside of brackets and in my first post.

You may need to .....TAKE YOUR AMP AND HAVE IT SERVICED smile.gif


Tube amps are living breathing things that need love and care. They can get banged up on the back of a truck during shipping. So take it to somebody you trust and they might sort it out quick/cheap smile.gif



QUOTE (klasaine @ Jun 1 2015, 11:39 AM) *
Well, if it really is 120 hz noise then it's a filter cap but as Todd mentions, w/o actually hearing it we can't really know anything.

*120 hz is right in between Bb and B.


This post has been edited by Todd Simpson: Jun 2 2015, 07:47 PM


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