Vintage Monitor 10B tweeter replacement does not get ride of buzz

nms

Hi guys.

A little recap: noticed a "buzz" in left sl2000 tweeter a couple of days ago. Assumed it was a bad tweeter. Ordered RD0-194s from Polk; they came in today. Threw them in the speakers, buzz is still there. This leads me to think it's either the internal wiring or the crossover. How do you suggest I locate the problem and fix it?

The buzz is most noticeable when playing piano music (ex: George Winston).

thanks!

dorokusai

Swap the speaker wires and see if the buzz follows the wire or stays with the loudspeaker.

nms

dorokusai wrote: »

Swap the speaker wires and see if the buzz follows the wire or stays with the loudspeaker.

Did that (twice). It's definitely internal to the speaker.

dorokusai

It's time to open them up then.

nms

dorokusai wrote: »

It's time to open them up then.

I've got the panel off the rear. Only problem is I have no clue what I'm looking for. I've never messed with electronics like this before. It's not like you can tell a component is bad just by glancing at it.

Should I take a voltmeter and start looking at resistances, capacitances, etc of each individual component?

Is it likely the problem is in a loose connection, or a component on the crossover gone bad?

In short, I'm looking for guidance on how to approach locating the problem.

Thanks.

[Deleted User]

Hello,
While not impossible, it is doubtful, that the crossover could cause a buzzing sound. In my experience it is probably being caused by one of the 6.5" drivers operating at a frequency close to the crossover frequency of the tweeter and driver. To test this theory try using a medium sized pillow to cover the tweeter and see if you can still hear the bad sound. If so, try and narrow down which driver it is.
Regards, Ken

nms

Kenneth Swauger wrote: »

Hello,
While not impossible, it is doubtful, that the crossover could cause a buzzing sound. In my experience it is probably being caused by one of the 6.5" drivers operating at a frequency close to the crossover frequency of the tweeter and driver. To test this theory try using a medium sized pillow to cover the tweeter and see if you can still hear the bad sound. If so, try and narrow down which driver it is.
Regards, Ken

Thanks for the advice. Did what you described - held a pillow in front of the tweeter: buzz went away. Held pillow in front of midranges: buzz very prominent.

Test was done twice.

This done while playing George Winston.

Thanks!

nms

UPDATE: I've gone back to the sl2000s to avoid frying my new RD0s in case the problem does lie in the crossover. Tweeter buzz/hiss is noticeably worse with the old tweeter.

Is it possible for a polyswitch to cause a tweeter to make these noises?

nms

Without doing anything drastic I've tried shorting out the polyswitch by squeezing the leads together. It looks like they made contact, but I can't be 100% sure and I don't want to do anything permanent yet. Shorting the polyswitch made no difference in sound quality.

C'mon guys I need help!

Should I cut the polyswitch off the board?

EDIT: I should add that I've been doing a lot of searching through the forum in the past few hours and I haven't found anything that jumps out at me as a possible solution.

Thanks.

John in MA

Offhand without looking at a schematic, there's usually not much else perishable between the inputs and the tweeter other than a capacitor or two. My guess is one of those is failing.

nms

I tried to check the caps with an ohmmeter but the needle immediately pegs at zero resistance on every cap. Shouldn't it be infinite resistance until the cap "fills up"?

Resistance measured from the external wire posts also pegs at zero, so either I'm not using the ohmmeter right (very likely) or something is seriously broken (unlikely b/c the speaker still works).

nms

polyswitch has been shorted with solder. Sound is unchanged.

lightman1

What are you using to play tunes through the carver?

nms

lightman1 wrote: »

What are you using to play tunes through the carver?

ipod (yeah I know). I'm running through the headphone jack into a cable that has a headphone plug on 1 end and RCA plugs on the other.

OK, I see where you're going with this. Just for grins I played a piece on my PC (also connected to the receiver) and it does the same thing (fuzzy tweeter). I like your thinking though!

F1nut

You've got a bad cap or two. Time to upgrade the crossovers.

nms

F1nut wrote: »

You've got a bad cap or two. Time to upgrade the crossovers.

How much is that going to cost me? I'm (probably) buying a pair of SDA 2As Sat, so I don't want to dump much $ into the 10s.

Glad you discovered my other thread

dorokusai

If that's the problem, not very much. I would swap crossovers between the speakers first.

www.partsexpress.com

ben62670

Yep. Caps go bad over time.

nms

dorokusai wrote: »

If that's the problem, not very much. I would swap crossovers between the speakers first.

www.partsexpress.com

Hmm... Doesn't that mean I have to de-solder some wires?:eek: I'll take a stab at it tomorrow. Thanks for the suggestion.

lightman1

nms wrote: »

ipod (yeah I know). I'm running through the headphone jack into a cable that has a headphone plug on 1 end and RCA plugs on the other.

OK, I see where you're going with this. Just for grins I played a piece on my PC (also connected to the receiver) and it does the same thing (fuzzy tweeter). I like your thinking though!

Just a thought is all. Sometimes I'll burn a CD from my I-tunes,Rhapsody, etc. through Media Player and I'll get a slight buzz or a static "click" every once in a while. My Bro is setting up a lossless FLAC file to send me....???? Maybe it's in the source..??

nms

lightman1 wrote: »

Just a thought is all. Sometimes I'll burn a CD from my I-tunes,Rhapsody, etc. through Media Player and I'll get a slight buzz or a static "click" every once in a while. My Bro is setting up a lossless FLAC file to send me....???? Maybe it's in the source..??

I actually have some rips that have what you're describing. However, most of my files appear to be very clean even at high volume levels when played on various systems. Additionally, the piece I played from my PC was from a Carver test/calibration CD, so a different source than my personal rips. This piece also exhibited the same tweeter noise issues.

The pops and clicks that bad rips have sound quite different to me than what I am hearing: they have a harsh, almost digital quality to them, where the tweeter buzz has a softer feel to it: when a piano note is played, the attack of the note sounds fairly good, but the hiss/buzz builds when the note fades off (if that makes any sense).

Thanks for all the input guys.

lightman1

Caps.

nms

Should I do the resistors as well?

ben62670

nms wrote: »

Should I do the resistors as well?

You can test the resistors to see if they are in spec. If they are they don't need replacing. Now that I said that I have replace my resistors in my recap jobs. Mills cost around $20 to do all 4. If I didn't do them I would be wondering if I had done them if it would have made them better. While you are ordering the caps I would do the resistors too. IMHO

lightman1

Do you change your oil without changing the filter?;)
If you're gonna do it, do it all the way. I'm still working on my SDA
x-overs,FWIW.

ben62670

lightman1 wrote: »

Do you change your oil without changing the filter?;)
If you're gonna do it, do it all the way. I'm still working on my SDA
x-overs,FWIW.

Not apples, and apples, but I agree:)

nms

Thanks for all the advice tonight guys. I'll take a look at swapping the X-overs tomorrow as a final test, and then order the parts.

Thanks again. I don't know what I'd do without this place!

lightman1

nms wrote: »

Thanks for all the advice tonight guys. I'll take a look at swapping the X-overs tomorrow as a final test, and then order the parts.

Thanks again. I don't know what I'd do without this place!

Heavy drinkin' and Bose HT listenin' probably. GO PACK!:D

dorokusai

Don't start replacing things if the problem doesn't follow the crossover.

The old caps stigma is deep and its easy to suggest new this or that.

nms

dorokusai wrote: »

Don't start replacing things if the problem doesn't follow the crossover.

The old caps stigma is deep and its easy to suggest new this or that.

Definitely - if it ain't broke don't fix it. I'll also see if I can get hold of a multimeter tomorrow to check the capacitance before I swap the X-overs.

lightman1

dorokusai wrote: »

Don't start replacing things if the problem doesn't follow the crossover.

The old caps stigma is deep and its easy to suggest new this or that.

Fair enough. But wouldn't a cap lose it's speed to discharge voltage over the years?
Fishing.