Troubleshooting suspected blown bass driver in Wharfdale Super Linton 30D?

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Nicholas M

New Member
Hey everyone. I have a pair of vintage Wharfdale Super Linton 30D loudspeakers hooked up to an old Technics SU Z35 amp and a Dual 504 turntable I just acquired yesterday. The amp is being used while my Marantz 2230 is getting a blanket recap and power supply replacement. Just yesterday I was hooking up my Dual 504 to the receiver and grounded the wire to the amp and began to immediately hear distortion out of the bass driver on my right channel speaker. It can be heard across all inputs e.g., phono, aux, and tuner, and increases with volume. Cables are grounded to the amp and speaker because of age, no banana plugs. Does it sound like a blown bass driver? Cone is not ripped and is intact, could it be a melted coil? Mostly playing jazz and light rock with loudness switch but not really cranking it. Amp holds 8omhs with the speaker. Any advice would be super helpful....not sure if I've got a dead speaker on my hands or what :(
 
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goodolpg said:
Can you check the woofer with a multimeter and let us know what reading you get.
Click to expand...
good advice -- Don't have a multi meter but if after lightly pressing the cone I'm hearing scratching, wouldn't that indicate a damaged coil? Just trying to cheap troubleshoot before I buy a multi.
 
Could be bad spider or surround as well I think.
A meter can be had for around $20 at most big box stores and you said you wanted to determine if the driver is bad.
I suppose you could try the "bad" woofer in the other speaker cabinet and see if it still makes bad sounds.
I assume you were connecting things with the power on?
If yes I'm not sure you should try connecting the woofer direct to your receiver.
 
Actually just captured a replacement driver for £20 off Ebay so i'm going to replace it and see if the problem persists...
 
Did you swap the speakers? That is, connect the left speaker to the right channel from the amp and vice versa for the other speaker. If the problem stays with the same speaker, then you have a speaker problem. If the problem stays with the channel (that is, the other speaker now sounds bad), you have an upstream (non-speaker) problem.

Also, can you be more specific on which wires you were messing with? You mention the turntable and then mention banana plugs. The turntable should have RCA connectors at the end of the cables. I am not sure how you could ground out RCA cables. Or were you messing with the wires between the amp and your speakers?

When making wiring changes, only do it when everything is powered off. Shorting the speaker outputs on the amp can blow the amp. An unexpected pulse, like shorting an input, can have disastrous results as the pulse is amplified and sent to the speakers. That is why it is a good idea to switch off the speakers or turn down the volume when messing with the turntable. A needle drop has been known to blow speakers.
 
Super informative reply thank you.

1. Yes I did swap the speaker from AMP only and noticed the distortion follows the speaker, not the channel ... which I think rules out a malfunctioning amp. So to be specific about wires -- its grounds from speaker to amp, no banana plugs. Record player is RCA phono input but output is same distortion as other formats e.g., tuner, aux. The wires between amp and speaker are generic, seem old, but not terrible... I suspect they're not the issue... but it's strange because yesterday I introduced the record player into the circuit and before that it worked fine to my ear but now I hear loud distortion on that right channel bass driver. Sure -- all wiring is done with power off of course :). To be fair, though, not when I was plugging RCA into the amp when I set up the turntable yesterday and naturally I got a lot of feedback out of the bass -- could that have potentially blown it ? Or is it blown? I preemptively sourced a replacement driver of the same unit for cheap so Ill plan to replace but I see the soldering and not sure how to disassemble that from the driver and crossover.. any thoughts? that's the next part I'll need advice on. Just hoping I get this sorted before my Marantz 2230 comes back soon from a blanket recap and power supply replace.

Thanks!!!
 
" its grounds from speaker to amp" Can you elaborate?
I'm familiar with turntable ground wires but not with speaker ground wires.
Do you mean the speaker wires themselves?
Ok, just realized you may be overseas, maybe what we call wires/cables/leads you call grounds?

Hopefully the new driver will fix the problem as it's a cheap enough price:thumbsup:
 
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Sure Goodolpg,

It's bare wire connector both to the amp (no plugs) and the back of the speakers (not built in, no plugs, just screw on grounds). There are no speaker wires, I just had extra external speaker wire that I connected from my amp to my speakers. Can take photos if it's unclear. Waiting on the new driver but also need to buy a soldering kit , how easy is it to solder off the old connectors and then resolder for the new driver? What about the crossover?

I'm nervous about it but also think I can do this myself.... I also haven't definitely ruled out a blown driver as without a multimeter I can't definitely say it's blown.

Any advice on driver replacement? That's the next step!
 
It shouldn't be a problem replacing the driver and there should be no changes required with the crossover if the replacement driver is identical to the old one. There are also video tutorials for good soldering practices on YouTube. You shouldn't have issues soldering speaker connections as long as you have a steady hand.
 
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Nicholas M said:
Sure Goodolpg,

It's bare wire connector both to the amp (no plugs) and the back of the speakers (not built in, no plugs, just screw on grounds). that I connected from my amp to my speakers. Can take photos if it's unclear. Waiting on the new driver but also need to buy a soldering kit , how easy is it to solder off the old connectors and then resolder for the new driver? What about the crossover?

I'm nervous about it but also think I can do this myself.... I also haven't definitely ruled out a blown driver as without a multimeter I can't definitely say it's blown.

Any advice on driver replacement? That's the next step!
Click to expand...

I'm still confused but maybe it's just me. This seems to contradict itself "There are no speaker wires, I just had extra external speaker wire"

Just guessing I assume you have push on terminals, are they like this image?
upload_2023-3-19_22-4-38.jpeg
If yes I'd just cut the old ends of and install new crimp on connector ends like these, should be available at auto parts store or big box lumber stores if you have those where you are.
images
g120FQS10PK-F.jpeg


If they are soldered on you may need to desolder and then resolder as you mentioned. Youtube videos are often a good place for learning some techniques one is not familiar with.
 
So basically it's just speaker wire with exposed ends, one end goes into twist terminal or push terminal on my Marantz, the other end is screw grounded onto the backpanel of the speakers. Yeah I guess I can try and resolder myself... but not sure how to do that. Need to watch a video on youtube. However after speaking with my repair guy today he said it's strange for the bass driver to fail like that if I'm not overloading... he thinks it might be the crossover... any ideas or theories?
 
It could be the crossover. Take a picture of it and post it here so we can see the components. Also, have you checked the resistance of the bad driver with a multimeter as @goodolpg suggested?
 
Will post photos today. No I did not, can that be done whilst the driver in question is still installed, or should it be taken out to access the VC?
 
Front, rear, inside.
 

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Check the driver resistance at the driver's terminals.
It appears you can use a female quick-disconnect (QD) terminals on this driver. I would install QD terminals after cutting the wires attached to the driver instead of soldering the wires back on, as @goodolpg recommends.

QD terminals.png
 
Nicholas M said:
To be fair, though, not when I was plugging RCA into the amp when I set up the turntable yesterday and naturally I got a lot of feedback out of the bass -- could that have potentially blown it ? Or is it blown? I preemptively sourced a replacement driver of the same unit for cheap so Ill plan to replace but I see the soldering and not sure how to disassemble that from the driver and crossover.. any thoughts? that's the next part I'll need advice on.
Click to expand...
Potentially you may have blown the driver by plugging the turntable RCA into the amp while powered on, as @RTally said. You can also slave the new driver into the speaker (power off, of course!), turn on some music and see if the noise is gone.
 
That seems the most likely culprit because when I put RCA in the amp was on -- is that a common occurence? so best step now is to replace the driver and see if the noise is gone, yeah?
 
So to be clear, use a multimeter on the driver terminals to gauge resistance -- anything around 1-3 ohms would be insufficient, yeah? and if so, snip the wires above the terminal and install female QD terminals (2) onto the exposes wires ? I'm having trouble understanding how the QD links the driver to the crossover. Thanks guys
 
Wouldn't this course of action still require tinning and soldering to the ports of the QD? Or can you just insert bare wire into those tubes?
 
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