Crackling volume knob

 

Bronze Member
Username: Liquid_sun

Post Number: 73
Registered: Apr-10
Sometimes, whenever I adjust the volume knob it crackles loudly. Once the knob is in place, and no longer rotating the signal is clean with no problems. Turn it back and forth several times while the amp is off always helps but only for few days. Afterwards the problem appears again. Is there anyway i can rid of the crackling noise permanently?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18684
Registered: May-04
.

Easiest method is simply rotating the VC with the component powered down. Oxidation is the problem with noisy VC's. Simply get fairly aggressive about moving the VC for about 30 seconds. This should clear up the problem - at least temporarily.

Noise tends to eventually return and after a while the control needs more than just some wigglin' around. The next step in cleaning the VC is done with a syringe and some isopropyl alcohol. Remove the cover of the amplifier - with it unplugged from the AC outlet - and look for a small hole in the metal can surrounding the control. Squirt a minimal amount of alcohol into the VC and do the aggressive wiggling thing again. Be careful not to drown the control in liquid or you'll have more of a problem than just a noisy control. Allow all liquid to evaporate before you power up the amp.

If that doesn't last long enough for you, you can try some contact cleaner. You might want to contact Marantz for a suggestion but most manufacturers will suggest taking the component to an authorized service center. Not a bad idea but, otherwise, buy a decent cleaner and repeat the actions of squirting and wiggling. Use a minimal amount of cleaner.

If the problem stills persists, have the amp looked at by a tech. They should do a full clean up of the in/out jacks and any internal components which might need some maintenance. Maintenance by a tech also typically includes running it on a scope to check for proper operation; full power output, distortion, noise, etc. Cost is probably going to be about $60 or so.

https://www.pcbtoolexpert.com/best-electronic-contact-cleaner/


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Bronze Member
Username: Liquid_sun

Post Number: 76
Registered: Apr-10
Its been a two or three weeks without any problem. Thank you very much, hope so the problem wont appear again.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18687
Registered: May-04
.

Maintenance is something every system owner should do at least once a year. Oxidation occurs slowly and over months. Taking apart connections and cleaning the connectors is time well spent. This is particularly true for any RCA's or plug/jack type connections. If you use a turntable, there are numerous connections made between the cartridge and the input to the pre amp. Recheck tonearm balance and anti-skate, VTA if adjustable. Make sure they are all in pristine condition. It can, in some cases, be the difference between owning the $2k pre amp or the $3k pre amp Or upping the quality of your source player. Remember, most of your system, and certainly the details found in higher quality systems, comes in the micro and mili-Volt level signals.

Any mechanical part with easy access should be cleaned at that time. Even if the control isn't making noise, it won't hurt to clean the contacts. No need to be aggressive if there are no problems but make sure the controls are operating at their best. Go through your system and look at the condition of everything you did to put the system together.

Either remove or replace oxidized speaker cable ends. If you use spade lugs, clean the surfaces. If you use bare wire, trim back the dielectric to show new, fresh copper. Recheck the quality of the connection and tighten down connectors to a secure hand tightened condition. Pay particular attention to grounding points in the system as they are the most likely source of low level noises in the system. One value you will obtain with a more expensive component is probably a quietness (a black silence) that can be devalued by poor grounding techniques. Star grounding typically pays off if it's done well. Before you invest in noise reduction devices, make sure your system is at its best. People tend to spend money on accessory devices to insert into the system without first checking for any bottlenecks which might defeat the money spent.

No need to work hard, this is lazy Saturday afternoon stuff. You can actually crack a circuit board if you're not careful or strip the threads on a binding post. But gentle care will typically pay off. Don't use sand paper on any connector, you want smooth mating surfaces that are unscratched. Obviously, don't use steel wool for anything in your system. If you intend to use any connection enhancing fluids or creams, make sure the connectors are clean and listen to that condition before you apply the enhancer. Tweaks are generally cumulative where one builds on another. If a tweak doesn't seem to be giving you a benefit, maybe the system needs to be more transparent to the source before tweaks will make an improvement.

After a while, you've grown accustom to your system's performance. When you're doing maintenance ask whether there's anything you could do or change that might improve the system. Maybe a slight change in speaker position (get out your tape measures and your levels) or just make sure your speakers are secured to their stands and stands are well grounded to the floor. Most components in a more transparent system respond to what they are sitting on. Isolation in an audio system is always a balance between using mass and not using mass. "Mass" is slow and difficult to excite but once it is set into resonance, it holds onto that resonance for a long time. Alternatively, low mass is quick to excite but also quick to release its resonance. High mass produce resonances which exist in the lower frequencies while low mass tends to produce resonances in higher frequencies. A little thinking and some truthful experimentation (better? or just different?) can make an audible improvement without spending lots of money.

Amplification devices and most source players require isolation from external forces which might create internal resonances but also benefit from mechanical grounding which drains away internal vibrations. That's a rather tricky balancing act that requires some amount of thought before you just toss an isolation device under your components. You may actually be making things worse if you only address one side of the component's needs.

Try a few coins under the spikes of the component/speaker stands and then listen to some familiar music. Isolation devices that both isolate and transfer energy away from the component are worth the money. You don't have to spend a lot. I found several of my favorite isolation devices at Home Depot. A cloth bag of tennis or racket balls under a component can make a noticeable improvement. However, just tossing a bag under your amplifier might not benefit anything and might actually make things worse. Don't think just doing what others have told you about will work in your system.
Experiment and, most of all, listen.

Most aftermarket devices came from someone trying something generic and then tweaking it into a sellable product. Typically, the tweaking is more for cosmetic purposes than for audible changes made. Packaging always makes up a substantial part of most product's cost to the consumer. Always remember, 99% of your system's performance is perception rather than simple hearing.

If you're making changes, even if it's just simple maintenance, don't overdo your changes all at one time. Only change one thing (overall maintenance qualifies as one thing) and then listen for what has changed. Is the system actually better? Or, has something simply changed? "Better" or "just different" is a fairly important thing to understand as you upgrade your system.

If nothing else, this yearly maintenance is similar to the gardener going out to determine the condition of their soil and plants. Visually inspect your components and their set up and take care of any "weeds" that might have popped up. Notice any blank spots that need to be filled in. Nature abhors a vacuum unless it's inside a tube.


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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18688
Registered: May-04
.

And when you make any change to your system, always keep notes on where you began and what you changed or how you changed the system. If you know where you were, you can always go back to that location if something doesn't work out. If you change without a plan, you might stumble on something along the way but the chances are most likely you won't - at least not on the first try.

Keep a good journal of whatever you do to your system. Look at it occasionally and determine whether you truly have made the system better or just different.



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