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Speaker Crackle

miversen

miversen

New Member
New to the site and vintage audio. This probably has been asked and answered. I was given my dad's old Sony STR-6046A receiver and two Venturi formula 4 speakers. I am getting random speaker crackle. At first I tried the radio and was getting some speaker crackle. I wasn't sure if it was just a bad FM signal. So, I plugged in a blue tooth to RCA device into the AUX input and still get crackle. I haven't tried the turntable yet to see what that sounds like. Can someone please help with suggestions on some trouble shooting?
 

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Pull the grills and make sure the speakers are intact, they should look like these also and it wouldn't hurt move the knobs back and forth

Screen Shot 2024-08-19 at 6.40.58 PM.png

When was the last time the Sony was used prior to you? the reason I ask is if it's been sitting idle for an extended period of time it could need something as simple as some *DeoxIt

Or possibly some basic service by a technician if it has never been serviced and still has all the 50+ yr old parts

*

The Idiot's Guide to Using DeOxit (revisited)

Moderator’s note: we have an updated and condensed version of the following here: https://audiokarma.org/forums/index.php?threads/tldr-deoxit-guide.850968/ I was asked to re-post this semi-ancient post that has been long buried in the archives and I was reluctant to re-post anything already in...
www.audiokarma.org

Don't let the title of that thread insult, it's a play on words and a good thread on how and why that stuffs works
 
Thank you for your response. When I take the grills off they look just like your picture. Except one of the mid's nipples is dented in but intact. I'll try the DeOxit and let you know if it worked or not. It has been a while sense the Sony was used. I remember my dad getting a new Sony and new speakers in the early 90's. So, I guessing it has been that long. There is a local guy who can fix the speakers if need be but I'm hoping the DeOxit works.
 
I gree with working the knobs on the speakers back and forth a few times.
There could be carbon build up on that potentiometers. It may even crackle if you turn them whith the receiver on. Or it could be dirty controls on the receiver itself. Like volume control, tone controls, ballance control, etc.
One way to make sure it isn't the reciever is to use a different pair of speakers hooked up to the receiver.
But I would start with the speaker controls first.
 
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Lavane said:
I gree with working the knobs on the speakers back and forth a few times.
There could be carbon build up on that potentiometers. It may even crackle if you turn them whith the receiver on. Or it could be dirty controls on the receiver itself. Like volume control, tone controls, ballance control, etc.
One way to make sure it isn't the reciever is to use a different pair of speakers hooked up to the receiver.
But I would start with the speaker controls first.
Click to expand...
I swapped out the Venturi's with known working speakers. The crackle continued. Looks like I'll start with cleaning the controls on the receiver. Thank you for the advise.
 
Dswankey said:
Pull the grills and make sure the speakers are intact, they should look like these also and it wouldn't hurt move the knobs back and forth

View attachment 3277980

When was the last time the Sony was used prior to you? the reason I ask is if it's been sitting idle for an extended period of time it could need something as simple as some *DeoxIt

Or possibly some basic service by a technician if it has never been serviced and still has all the 50+ yr old parts

*

The Idiot's Guide to Using DeOxit (revisited)

Moderator’s note: we have an updated and condensed version of the following here: https://audiokarma.org/forums/index.php?threads/tldr-deoxit-guide.850968/ I was asked to re-post this semi-ancient post that has been long buried in the archives and I was reluctant to re-post anything already in...
www.audiokarma.org

Don't let the title of that thread insult, it's a play on words and a good thread on how and why that stuffs works
Click to expand...
Thank you for your response. When I take the grills off they look just like your picture. Except one of the mid's nipples is dented in but intact. I'll try the DeOxit and let you know if it worked or not. It has been a while sense the Sony was used. I remember my dad getting a new Sony and new speakers in the early 90's. So, I guessing it has been that long. There is a local guy who can fix the speakers if need be but I'm hoping the DeOxit works. Last night I swapped out the Venturi's with known working speakers and the crackle continued. Tonight is cleaning the receiver.
 
borchee said:
Have you tried both speaker outputs, A and B? Excersise those switches, perhaps it is them; but anyway, the receiver will need at least a go-through.
Click to expand...
B has more crackle than A. It seems to be every thing I adjust creates the crackle.
 
miversen said:
I'm pretty sure its crackle. How would I know the difference?
Click to expand...
One sounds like crushing a bag of chips, and one sounds like cooking bacon - can't remember which is which though.

You got good advise above and switching the speakers out was a good move to isolate the problem. I hope the cleaning does the job.
 
Try and get some contact cleaner in those selector switches as well along with the main selector switch. Work the rotory pots back and forth about 30 times each after cleaning. Don't get too carried away with the buttons though. If the crackling is still there, it may be anything from a failing cap to small signal transistors going noisy. Therw are some known not to age well.
 
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Your Sony STR-6046A dates from 1974. If it has never been serviced it is WAY past due. There are a multitude of possible reasons for the noise you are hearing such as dirty pots, bad electrolytic caps, bad transistors, bad STK modules and/or cold solder joints are but a few.

If you want to try cleaning the pots first you have to remove the case and bottom cover to access them. You need to get the DeoxIT F5 into the internals of the pots before working the shaft back and forth. I circled the pots in red.
20240820_180159.jpg

Another common issue are the infamous little 3 legged transistors from that time frame. If the legs on yours are black they should be replaced. I've circled some of those in red so you know what to look at.
20240820_180459.jpg

My suggestion is take it to a repair shop and have it gone through.
 
F1nut said:
Your Sony STR-6046A dates from 1974. If it has never been serviced it is WAY past due. There are a multitude of possible reasons for the noise you are hearing such as dirty pots, bad electrolytic caps, bad transistors, bad STK modules and/or cold solder joints are but a few.

If you want to try cleaning the pots first you have to remove the case and bottom cover to access them. You need to get the DeoxIT F5 into the internals of the pots before working the shaft back and forth. I circled the pots in red.
View attachment 3278629

Another common issue are the infamous little 3 legged transistors from that time frame. If the legs on yours are black they should be replaced. I've circled some of those in red so you know what to look at.
View attachment 3278631

My suggestion is take it to a repair shop and have it gone through.
Click to expand...
Ya, I ran into signal transistors in various Marantz pieces of equipment that are known to go noisy. The drivers in a Sony power amp had black corroded legs.
 
i have some experience with this unit, my suggestion is: if you plan on listening to fm radio and want to listen to stereo, make sure fm stereo is working FIRST. if not, have a tech repair it. this unit is notorious for fm stereo going out and while there is a fix for it, it does not always work.

only after you sort out fm stereo should the rest of the unit be gone thru. there are a bunch of 2sc631/2sc632 thru-out the unit and they should be replaced.

the only thing more frustrating than going thru a unit and replacing transistors and capacitors and cleaning controls only to find that you can't get fm stereo to work is paying someone to come to the same conclusion.

if you don't care about fm stereo then disregard all of that but keep in mind that it is an stk unit and if you blow a module, you are pretty much sol.

edit: i had the known stereo issue confused with the 6060f(i think). but i still had no fm stereo on the 6046a and couldn't get it working. i've got a parts unit with good stks if you need anything for the 6046a. good luck.
 
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Update...
I took the covers off of my receiver there was a lot less dust than I expected(good thing my dad kept in a box). I cleaned out the pots and what not but haven't turned it back on yet. On some of the twist knobs I could feel grim when I turned them. After the cleaning I noticed they moved more freely. I'll post an update if this solved the issues.speakers.jpg
Speakers with the grills off.
 
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