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Troubleshooting a quiet tweeter

Y

Yent

New Member
Hey all!

So glad I found this forum as I am at my wits end!

I have an old NAD 3020 & a set of TDL Nucleus 1 speakers that have been in storage for a few years since moving home.

I just managed to finally get my hands on them & after repairing a small tear in one of the mid drivers (using a mix of 20% PVA 10% Gorilla Wood Glue 5% epoxy & 65% water) this seemed to have done the job!

Now the amp itself has seen better days, treble & balance are a bit dead, loudness is dead & volume is a bit fuzzy. The only channel that works properly seems to be aux - I'm presuming this is because the capacitors are dead/dying.

I'm more than happy running off aux for now & the speaker I repaired seems to be working fine now.

The trouble I'm now having is that the other speakers tweeter is extremely muted - I have isolated the tweeter & there is definitely sound; you just have to really drive it.

I have checked the crossover panel & nothing seems to be blown or dead & looks like it's in good condition - I'm guessing that the capacitor for the tweeter needs to be replaced & this is where I think I will need some help.

The capacitor is a Yontex Bi-polar 5.6uF 100WV - I'm having trouble sourcing the exact part, or another manufacturer with the same specs & this poses a question that I have yet to find an answer; Do I replace just the one cap, or both caps in both speakers as this will effect the sound l? If I am replacing these two, should i go ahead & replace the two driving the mid drivers?

Would appreciate any insight into this you may offer!
 
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Yent said:
I have checked the crossover panel & nothing seems to be blown or dead & looks like it's in good condition - I'm guessing that the capacitor for the tweeter needs to be replaced & this is where I think I will need some help.
Welcome to A.k.
The capacitor is a Yontex Bi-polar 5.6uF
Click to expand...
G'day Don't know 'yontex'
retrace the circuit.. 5.6uf seems out of spec.. more like 3uf or lower for a tweeter. then again I don't know the speakers 2 way or 3 way and it might be a combo tweet mid?
Could look up Dayton audio speaker caps/ poly's.
 
Thanks for the response! I have uploaded some pictures of the crossover panel -

https://imgur.com/a/LX5Mvlk

Apologies for focusing on the Capacitors, but it looks to me they are 2 way (one large coil for larger capacitor & a small coil, capacitor & a ?resistor?)

As you can see I think the 5.6uF size is right for the smaller capacitor.

Do you have any insight into replacing all caps? Or just the one that I think has failed?

If i cannot find 5.6uF capacitors, will a 6uF work & will this affect the sound at all?

Cheers!
 
Aside... On the nad 3020 ... Are you planning on a recap? probably need to clean the pots and switches anyway.
Plenty of 3020 projects on A.k.
 
Thanks for your response Binkman, really appreciated!

I do not own a multimeter so I havent tested as you said - this is all just assumptions at this point!

You are correct - seems to be pretty poorly terminated so I will be cleaning these up when I solder in the new caps.

As to the NAD - I was going to clean the pots & switches, but I imagine a recap on this would be rather expensive & I havent soldered in a good few years so I will probably leave as is - if the Aux channel goes then I will probably look to do this as both speakers & amp have a lot of sentimental value to me & I do love the sound I get!

Would you recommend recapping all capacitors in both speakers? Will different caps produce different sound do you know?
 
Considering the price of a few caps the shipping will cost more than parts ordered so you might as well get some deoxit. could clean up some selector switch issues

You can vary speaker caps uf rating a bit decimal point wise but these cap values are common for speakers and more than one supplier has them and sounds like they match your amp. so keep the caps uf. you can up the Voltage rating.
 
I'd test the tweeter out of the circuit , or swap tweeters between speakers before starting to replace parts. Perhaps your tweeter is bad and you spend $$ on capacitors that won't solve your problem.

Then, if you replace the capacitors, do both speakers.
 
First check is continuity and resistance. DC resistance of 8 ohm drivers should be in the 5-6 ohm range and 4 ohm drivers about half that. If it is open or very high resistance likely blown voice coil. If in or near that range you are probably in luck.

You can test a driver with a battery (AAA, AA, C, D) whichever you have handy and two wires, solid probably better. Attach one wire to + terminal and other to -. Holding wires to opposite ends of the battery one way will push the driver cone/dome out and other way in. Can sit there and tap one of the wires on the end of the battery and make the driver pop, click, whatever you want to call the noise. Have bought a pair of speakers before using that test they had sold the receiver had nothing to drive them with. Got a discount for one bad tweeter, it was screwed up. Other speaker was good. Fortunately Polk made some replacement tweeters for that model.
 
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