1982 Yamaha NS 50T Muffled Tonight

[Guest The man who fell to earth]

I bought these weeks ago, mostly for the stands that they came with.

They worked fine until tonight when the right speaker became muffled.

I switched the cables and it stayed with that speaker.

The tweeter works, just not as 'tweety' as the other by a long shot.

I took the drivers out to look at the wiring and the x-over. 

Only thing I noticed was that one off the inductors glue had failed and the inductor had slipped (would that cause an issue?)

If it's the crossover (see pic attached) is there a mod I could make to improve these typically harsh (neutral) speakers?

Or would it be cheaper/smarter to buy these https://www.ebay.com/itm/Yamaha-rebuilt-crossovers-NS-50T-speakers/323732609165?hash=item4b5ff7988d:g:Iu8AAOSwsK1chvnX considering I'm to time poor to be putting much effort into soldering (I just want to listen not tinker).

The values look higher on these than my crossover, but I cant find a schematic for the NS 50T. (The gold Nichicon looks to be 8uf the ebay crossover looks to be 20uf ? I can't make out the value on the ebay tweeter cap.

Thanks for reading.

Edited July 16, 2019 by The man who fell to earth
too wordy

[Al.M]

Try:

 

1. Checking the dislodged inductor has not completely disconnected from circuit board, if so resolder it.

2.Swapping left right cables from amp and CD.

3. Replacing the tweeter capacitor (soldering is easy or else throw the speaker in bin, so learn to solder)

 

If not those issues then most likely the tweeter is failing/failed due to:

 

1. Burnt voice coil which will need a speaker repairer to rewind it for around $60-100, or find spare on eBay.

2. The ferrofluid around voice coil is solidified due to age and needs cleaning and refill.

 

Google for speaker voice coil picture if you don’t know and DIY repairs to understand what is involved.

 

Properly check the tweeter is either at less intensity vs completed dead by covering woofer and ear against tweeter.

 

Replacing both tweeters with different ones will need the crossover circuit changed.

 

 

Edited July 16, 2019 by Al.M

[Guest The man who fell to earth]

Thank you,

Inductor still seems well soldered, just dislodged.

Tweeter is not completely dead just very muffled.

I switched speaker cables, same.

So next step is to recap. Just wondering why the ebay recapped guy has increased values (I can only see that the 8uf original he has replaced with a 20uf, not sure about the other cap from the photo.)

I guess I will order the same original values 8uf 400v and 15uf 50v Solen caps.

Thanks again.

 

[Guest The man who fell to earth]

Oh.... I see these speakers are not worthy of Solen caps. I'll shop around.

[Al.M]

Also, swap the tweeters from one cabinet to another to verify if the crossover is at fault.

[Guest The man who fell to earth]

Thank you AI.M

That is Golden help.

Not sure why I didn't think to do that.

I will feel much better ordering the caps when I am sure it's them. 

 

[Guest The man who fell to earth]

Switched the tweeters and the muffled stayed with the cabinet not the tweeter. So capacitor it must be. I forgot that when I turned it on last night I heard it fizzile and crackle. (I thought it was my dodgy old Yamaha CR640 receiver warming up, it needs love too, the pairing sounds very cold). 

Now to decide if I buy the ebay crossover with Solen caps for $100 (communication with the guy was promising so I am confident they are genuine Solen) or if I purchase cheaper caps and do it myself.

(Ebay guy replaced 15uf woofer with 20uf and the 8uf tweeter with 8.5uf).

Edited July 17, 2019 by The man who fell to earth

[Guest jakeyb77]

Don’t scrimp on the caps. 

I have had several versions of these speakers and they are really nicely made and great sounding speakers. 

I’ve had the 70’s and the 20’s. 

 

[Al.M]

Don’t get the eBay crossover, just change the capacitors which can be found here https://www.soundlabsgroup.com.au/c/Capacitors-Polypropylene/Capacitors+-+Poly.html middle price range metalised film type will do.

 

$25 soldering Iron from Jaycar etc.

Edited July 17, 2019 by Al.M

[Guest The man who fell to earth]

Thanks for the link AI.M and Jakeyb77.

They don't have the Auricaps in my values, and having read from HHH that the evo Mundorf is " Reasonably neutral with a slight emphasis towards higher frequencies making it sound a little more transparant than some darker, more rounded-off types." I'm thinking they are not suitable for these Yammys.

I'm wanting to be less 'hot' on the tweeter if anything, considering I'm using a same era Yamaha receiver.

I think I will purchase some Jantzen Standard Z-Cap from Speakerbug, unless someone can recommend a Capacitor with less eager tone to the highs without exceeding the speakers value.

Thanks heaps for the guidance.

 

[Al.M]

Should do, even generic yellow no name brand poly caps at $3-5 with about 5% tolerance on eBay. Jaycar or Altronics and similar places in your town will do.

[Guest The man who fell to earth]

I had a look in Jaycar. 

They had the yellow non polar Metallised Polypropylene Crossover Capacitors.

They only came in 250v and the ones coming out are 400v so I thought I better match that, so my nearest Jaycar is not a possibility.

Is it because these speakers are middle of the range that your helpfully suggesting that spending a bit more for basic Jantzen won't make a difference to my ears?

I will have these speakers for a while, and they sound a little harsh, I've never heard a good thing about the Jaycar caps, I was hoping the standard  Z Jantzen would be a tellable difference.

(Actually I just realised only the woofer has voltage on the cap of 400v - The very large gold cap for the tweeter shows no voltage just 8uf)

Edited July 18, 2019 by The man who fell to earth

[Guest jakeyb77]

Just contact Nigel at Speakerbug and order the good ones you like, or go to www.mouser.com and order what you need of wanting cheaper options. 

Simple. 

 

[Al.M]

250 or 400v caps doesn’t matter.

[Guest The man who fell to earth]

Thanks AI.M 

I am going to get cracking on this tonight I purchased an 8uf and a 20uf Jaycar yellow Suntan cap which are only 250v during lunch today, then my work buddy who is an electrician assured me that the capacitor would blow almost instantly because the voltage going through it would be too high. Then I got your message and now I an get busy again.

Once I've done the muddy speaker I will do the other speaker with the Jantzen and see if their is a difference to my ears. 

[Guest The man who fell to earth]

Yay !!! 

It was the crossover.

I chucked in the cheapish Jaycar cap and it solved the issue. 

I don't think the original cap was more than 250v anyway, doesn't say on it

However my ten year old daughter and I both prefer the un-recapped amp (I only did the tweeter cap tonight.)

The new cap sounds brighter and more detailed than the other. (wouldn't think much different after running in, but this is a first for me.)

I suppose many would say brighter/open is a good thing, but being a Yamaha playing through a Yamaha, I didn't need brighter.

Some day in the future I will spend money on much better caps and see how it goes.

'Suntan' what a cheap nasty name for a capacitor.

Thanks all for your help, all advice was much appreciated. 

I'll have a little bundle of c.ds and odds and ends coming up in 'pay it forward' soon as a meagre way of contributing instead of always taking up space. Ta!

Edited July 19, 2019 by The man who fell to earth

[HypnoToad]

The Suntan caps are probably going to be a lot better than the electrolytic's, speaker makers use them because they are cheaper, shame on you Yamaha.

 

As to the brightness it may be because the ESR (Equivalent Series Resistance) of electrolytic caps is much higher than film caps, making your tweeter a little louder for a start, you could try putting a 1 ohm / 10 watt wire wound resistor in series before the new cap, or even a higher value until you like the balance of the sound. Of course to balance things out you would have to change the capacitor and put the same resistor in the other speaker.

Edited July 20, 2019 by HypnoToad
Added details.

[Guest jakeyb77]

There is nothing wrong with the Nichicons used in the crossovers other than their age. 

[HypnoToad]

2 minutes ago, jakeyb77 said:

There is nothing wrong with the Nichicons used in the crossovers other than their age. 

 

Nothing wrong with them but film caps are better for audio than electrolytics, and the OP did say he got more detail out of the new film cap. But as I said they can upset the balance because of their much lower ESR. Add to this that the OP has gotten used to the sound of his speakers any change in balance will be noticeable. The "shame on you Yamaha" was "tongue in cheek" hence the "" after it, no offense intended.

 

[Al.M]

Good to see you it resolved. Havnt tried the latest Jaycar poly caps but previous yellow looking ones weren’t too bad, perhaps about 80-90% as good as a more fancy one but way better than the cheap $2 electrolytic caps.

[Guest The man who fell to earth]

The Jaycar cap at 8uf 250 volt was $17.95

Jantzen Standard Z cap 8.2uf $12.50 plus postage 

Jantzen Superior cap 8.2uf $70 plus postage

 

I'm going to do the next speaker with Jantzen Z cap, just for interest.

Then move on to the woofer caps because these speakers sound over dampened.

Very flat on bass and wooly if I turn bass up.

[HypnoToad]

3 minutes ago, The man who fell to earth said:

The Jaycar cap at 8uf 250 volt was $17.95

Jantzen Standard Z cap 8.2uf $12.50 plus postage 

Jantzen Superior cap 8.2uf $70 plus postage

 

That Jaycar cap was dear IMO, how about the Dayton ones I linked to below? And as to the difference between "exotic boutique" caps, the point of diminishing returns comes into play. Also bare in mind that they may be even more revealing the higher up you go, which may not be a good thing.

 

http://www.theloudspeakerkit.com/dmpc-8.2-8.2uf-250v-polypropylene-capacitor

.

[Guest The man who fell to earth]

The Jayar cap was a silly price for what it is,

Just the convenience of having a Friday night task, and weekend listening.

Thanks heaps for the Dayton link, I didn't find the aussie supplier.

I think due to my circumstances, I will choose the Daytons instead. Big Cheers

[Al.M]

In theory the woofer cap going from +ve to - ve wire (shunted) is not in the signal path and does affect sound as much vs the tweeter cap that isn’t (in series) so may only need an electrolytic cap similar to why Yamaha has it that way.

 

Jaycar cap was expensivish but it may just sound the same as the other alternative or maybe priced because it is quite good infact. Don’t worry.

 

Also, it will depending on how detailed your amp is to make any difference. I have generally found diminishing returns with expensive caps maybe around 10% better clarity but can also mean a lot if the speaker, amp and system is up to task. A midfi system with average detail and clarity won’t really justify better caps.

Edited July 20, 2019 by Al.M