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Home Theater => Audio => Amplifier => Topic started by: dell-tech on Oct 13, 2005 at 09:41 AM
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Hi all,
I hope you guys have time for a newbie's question.
I would just like to ask if you guys know of a gadget I can connect between my A/V receiver and my speakers to reduce noise/humming/static. ::) I've already found that the defect is with my receiver and would just like to know if there's still a way to remedy this problem other than buying a new one (amp) and throwing out this junk.
Thanks in advance for your help.
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you should have your amp repaired immediately or replace it. stop using it with your speakers as you might damage them (speakers)
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you should have your amp repaired immediately or replace it. stop using it with your speakers as you might damage them (speakers)
Thanks for the reply Iceman. I'll be taking your advice. Is just any electronics shop good enough or do you recommend a place where I can bring my AVR.
BTW, if there are other replies for such a gadget that might exist that can eliminate the static that comes from the AVR I'd be happy to try them also.
Thanks again.
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in my so many years trying to learn electronics, the only thing that I know of that is supposed to be in the middle of an amp and a speaker is a passive crossover which is probably already present inside your speaker. I have not heard of any gadget that can reduce hum by placing it before the speakers.
iceman's advice would be the best solution to your problem. my only question is how did you know that the amp is the problem? what is the amp's brand/model?
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Thank for the reply.
My AVR is a cheapo. A Sakura. I'm sorry but can't remember the model number. I'm sorry if you think my idea that such a gadget exists is dumb but I do think the output from the AVR is still a signal that electronics can control or filter. How that can be done is beyond me. I also am trying to learn a little electronics myself (had studied basic electronics - learned basic components and was able to complete a few kits but no way can I troubleshoot or repair.) * :D * Also you're right my speakers do have passive crossovers though that doesn't reduce the humming noise. * :o * BTW, I was able to isolate the noise by plugging in other speakers and disconnecting any sound input device and the humming sound is still heard even with zero level volume. I believe you that Iceman's advice would be best but while they're not yet sent for repairs, any advice would be welcome.
Thanks again.
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If you've isolated the source of hum as coming from your receiver, I'm not sure if there's any commerical after-amp device that can overcome the hum going to your speakers. A parametric equalizer can, but that's a preamp device. You can use a high pass filter to take out the offending hum, assuming you know the hum frequency, but you'd be taking out the deep bass as well. I suggest you get a good technician to check your receiver and have it repaired if that's really the cause of your hum.
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Thanks for the reply sir,
Yes, I've already isolated the hum to the avr by removing the audio source and plugging in other speakers and with zero volume, the humming noise can still be heard. I do believe that the amp will need repair but while it's not yet there, any idea if such a thing exists is welcome.
Thanks again.
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Hi,
No I didn't think it was dumb, in fact I think it's a valid question. However most ideal electronic principles insist that there must be nothing in between the amp and the speakers so it doesn't "colorize" the sound. Heck, even the passive crossovers are being debated by purists. But the crossovers are there to separate frequencies going to the woofers, tweeters, etc. and not to reduce any hum coming from the amp. Keep on it, electronics is a wonderful thing to do. ;)
Hey dude I like Sakura amps, I've been reading through several of their manuals and I'm impressed. I also heard that they welcome repairs as long as the unit hasn't been tampered with. You may probably have to ask the shop you got the amp from the details of the Sakura service center. But don't let this stop you from practicing your electronics. Since you've tried other speakers and the hum is still there, then your correct that the amp is the culprit.
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You can use a high pass filter if you know the frequencies of the hum, (maybe 60hz). It can filter out the hum by letting pass only the frequencies about the hum region (say, above 60hz). Or a notch filter if you know the exact center frequency of the hum. The construction would be similar to your passive network divider in speakers. But in doing so, the filter will also take out deep bass or a good part of bass. Not really a good idea. I suggest you have the receiver checked by a competent technician and correct the hum where it originates.
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I agree, I was going to suggest a "tank circuit" or is more known to be called a passive notch filter but it may seem to be a "plug" solution since a good working amp shouldn't have that much annoying hum which if left unchecked can even kill your tweeters...
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Hi all,
I hope you guys have time for a newbie's question.
I would just like to ask if you guys know of a gadget I can connect between my A/V receiver and my speakers to reduce noise/humming/static. ::) I've already found that the defect is with my receiver and would just like to know if there's still a way to remedy this problem other than buying a new one (amp) and throwing out this junk.
Thanks in advance for your help.
if i were you this is how i would proceed!
1. remove all input rca cables. leave the speaker connections as it is.
2. set input selector to cd, main volume control to zero, then power up.
3. if humming is present even with volume control set to minimum, then it could be your avr, have it repaired, if however the humming/static seems to go away, then proceed to next step.
4. turn the vulume control from minimum til 3'oclock, then back, is humming present? any crackling sounds? if so then have your avr repaired.
5. if after doing #4 and no humming was heard, reconnect the input rca cables one by one, then do #4, chances are you may have a defective cable.
good luck!
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Why spend for a device that would minimize the humm if you could have it repaired and eliminate the humm totally.
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hi JojoD818,
Thanks for thinking this subject is something to discuss. I'll be sending the amp for repairs this week.
This discussion has given me an idea of using a high pass filter to use with my mains to exclude frquencies below 6oHz and and then just let my subwoofer take care of anything below 80Hz. Will that work?
Thanks for your interest guys, special mention to JojoD818, av_phile1 and iceman. You guys are a lot of help.
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This discussion has given me an idea of using a high pass filter to use with my mains to exclude frquencies below 6oHz and and then just let my subwoofer take care of anything below 80Hz. Will that work?
the mains is 60hz, just puzzles me how and why you want to filter that out! i think you are mixed up now., the most sensible thing to do is have your amp repaired!
humming is a sign that something is wrong somewhere, the best thing to do is to find it and get it fixed, not with add-ons that contributes to complexity.
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for repairs this week.
This discussion has given me an idea of using a high pass filter to use with my mains to exclude frquencies below 6oHz and and then just let my subwoofer take care of anything below 80Hz. Will that work?
Thanks for your interest guys, special mention to JojoD818, av_phile1 and iceman. You guys are a lot of help.
You're welcome, but I really don't think this is an elegant solution. If your receiver is the hum source, feeding the sub through its LFE out might just route the hum to the subwoofer. You could feed the sub directly from the DVD player's LFE out, but unless the player has its own bass management circuit, you won't have much bass for materials that have no LFE signals. CDs included. FIltering out 60hz will take out much of the deep bass from your main speakers. And if you filter that out from your sub input as well, I don't see how the sub can do most of its job.
While you can work out a cheap high pass filter, I strongly suggest you have the receiver checked out. 2ny is right, a humming amplifer or receiver indicates a problem in the circuitry or surrounding conditions that simply must be solved. Addting filters won't. The hum signal is extracting more current than necessary, even idle current. So you eat more electricity than need be.
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Sir av_phile1 and 2ny,
Point taken sirs. As I've mentioned, I'm taking the amp for repairs this week. Di ko lang alam kung sa Sakura ko ba dadalhin o sa pinakamalapit na electronics shop na lang. If I don't find Sakura's service center, I'd probably do the latter.
Thank you for your advice. Will give you feedback when it comes back from repairs.
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it is best you take them to the service center for Sakura, they are qualified to do the servicing.
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dell-tech,
Glad to be of help. My advice to you is to seek help from the shop where you bought your unit and ask them where is the official Sakura service center. What I've heard is that even if the warranty has expired, Sakura service still accomodates "unopened" units. If you bring your unit to other repair centers then you'll surely miss on this opportunity.
On the note of using a hpf and sub, take avphile's advice. Your sub will just aggrevate the situation. But if you'll do this after you have the amp repaired then I'm sure you'll be surprised when watching your favorite movies. ;D
I'll try and see if I can get an address on Sakura's service center this afternoon.
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Thanks for the help sirs.
I've run a search already for Sakura's service center but to no avail. I'll certainly appreciate that info if you can get it...I'm sure a few others will feel the same. By the way this amp already received repairs before from Sakura but at that time, the unit was still under warranty. Sa Moses-Aaron ko rin dinala (yung pinagbilhan ko) - splendid service. I just don't feel that great bringing a unit to them that's already out of warranty tapos sila pa ang magdadala doon.
I already asked a nearby shop and the technician says for just PhP350.xx, he'll do the job.
And yes, I intended to do this setup (connecting a HPF and sub) after I get this repaired.
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Thanks for the help sirs.
I've run a search already for Sakura's service center but to no avail. I'll certainly appreciate that info if you can get it...I'm sure a few others will feel the same. By the way this amp already received repairs before from Sakura but at that time, the unit was still under warranty. Sa Moses-Aaron ko rin dinala (yung pinagbilhan ko) - splendid service. I just don't feel that great bringing a unit to them that's already out of warranty tapos sila pa ang magdadala doon.
I already asked a nearby shop and the technician says for just PhP350.xx, he'll do the job.
And yes, I intended to do this setup (connecting a HPF and sub) after I get this repaired.
I'd bring a defective unit to where I bought it anytime, with warranty or not. I'm sue Moses-Aaron would still entertain you but with their usual charges.
If a techie says he can solve your problem for P350, I think it's worth a try.
And once repaired, that is, the hum eliminated, I don't any point using an HPF.
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dell-tech,
I have talked to several shops this afternoon and they all (almost) said that it is possible (even without warranty) that you will only pay for the parts as long as the unit hasn't been tampered with. It seems that the guys that repair the brand Sakura only prefer to deal with shops rather than directly with the buyers. I will still try and find a way to squeeze some intel regarding their repair center.
Anyway, I urge you to bring it to the shop where you bought the unit, but I don't see anything wrong if your tech guy can do the job.
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bro!
just a good advice if I were you, ill dump my sakura. kse yung gagastusin mo sa pagpaparepair ng amp mo eh konti nalng you can buy a new one. hey sale na ang Konzert 502A, Php3500 nalng makaka discount kapa pero watch out for the immitation one. nag publish na ako dito how to know ang orig from the fakes, i knew this dahil sa direct supplier na ako kumuha ng 502A. hope this help.
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Hi all,
I just wanted to share my experience regarding the repair of my amp. The tech I brought the amp too failed to remove the humming noise coming from the amp and told me that he had tried to replace the fileter capacitors but to no avail. Asked him what else he suspects to cause the issue and he told me that it's the transformer. - I completely doubted that.
When I got home, I opened up the chassis and tried to repair it myself. I first tried to move the wires inside and check if there's just a losse connection. - some looked loose so I resoldered some of the connections. Then I looked at the PCBs and scratched the flax that I thought was making contact with nearby lines - same issue still. Next thing I tried was to remove the connection from the am tuner to the amp...the noise minimized..I then proceeded with removing all connections to the am/fm tuners and to my delight - the noise was gone.
Apparently, the noise was coming from the defective am/fm tuners that might have been damaged by a power surge. ???
My amp now is as good as new minus the am/fm tuners that I almost never used anyway.
God is good.
Thanks for all your help and advice guys. ::) :) :D ;D
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Good to hear you've corrected the humming problem yourself. There are very few things in this hobby, apart from the listening moments, that can be as satisfying as successfully troublehooting a gear. Happy listening. ;D
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You can't be more right sir.
Though now after eliminating the humming noise, the system I have now seems too bright, I'm thinking of adding a resistor to each of my tweeters. Do you think 5 ohms would be enough? Or, do you have other suggestions.
BTW, Do we have a thread about toning down brightness?
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You can't be more right sir.
Though now after eliminating the humming noise, the system I have now seems too bright, I'm thinking of adding a resistor to each of my tweeters. Do you think 5 ohms would be enough? Or, do you have other suggestions.
BTW, Do we have a thread about toning down brightness?
i can think of two right now, one is you can series connect a 12volt incandescent lamp, the type used in automobiles to your tweeter, this serves also to protect your tweeter, one thing nice about this is that at low levels this lamp does not subtruct anything from the signal, only when levels are really loud will this lamp is series have an effect!
then the other is the traditional L-pad attenuator, a 5watt 10ohm rheostat can be used, these can be pruchased from deeco i believe!
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then the other is the traditional L-pad attenuator, a 5watt 10ohm rheostat can be used, these can be pruchased from deeco i believe!
sir 2ny,
Thanks for the reply...will ask about this at deeco. But in the meantime I did purchase and connected a resistor (5 ohm 5 watts) in series with my tweeters and found a big improvement in terms of warmth of the sound. The tweeters now seem to emit a "cleaner sound" and the midrange seemed to now come alive when before it was clearly being overpowered by the tweeters.
And what's great is that the tweak only costs PhP20. ( I bought four resistors and a meter of lead). So for others who want to try this out feel free to do so.
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i have seen branded ones used halogen lamps even to protect their tweeters! ;D
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sir 2ny,
Oh yeah??? Wow, ok yun ah. ;D
I'll try that with a pair of bulbs from my christmas lights, I think that'll work.
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bulbs from christmas lights have high resistance! and ar not suitable! try those 12v halogen peanut types..
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i can think of two right now, one is you can series connect a 12volt incandescent lamp, the type used in automobiles to your tweeter, this serves also to protect your tweeter, one thing nice about this is that at low levels this lamp does not subtruct anything from the signal, only when levels are really loud will this lamp is series have an effect!
Galing nung advise mo Sir 2ny - practical and economic. More power to you.
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i saw this electronics book written by a filpino author at national bookstore, it describes several schemes to protect the tweeter, one of which even used a 2n3055 power transistor as control element!