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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 20th Jan 2019, 10:33 pm   #21
Edward Huggins
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Default Re: Speaker noises

These speakers were indeed rather poor. The driver units were (but not always) bog standard Goodmans commercial units with very basic 2 element crossovers. They gave a rather "one note" bass. Their rival company "Period High Fidelity" (also based in Maidenhead) used Peerless drive units and their speaker designs were far superior.
I nearly lost my job with Pye (who owned them) complaining about poor quality standards! Have many Members have noticed just how many Dynatron units suffer from frequent failure in one channel of their audio stages......?
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Old 20th Jan 2019, 11:15 pm   #22
InsertNameHere
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Default Re: Speaker noises

Quote:
Originally Posted by crackle View Post
Have you had these speakers long, do you know their history?
I wonder if they could have been poorly re-coned in the past.

Another thing to check is the inner suspension by the voice coil, has this come away from the speaker frame.
Does the speaker cone make a scratching noise when you push it with evenly spaced pressure.
I've had them for around a year and a half now, and I have no idea of their history, bought them just being told the basics and that the system (Player and speakers) is in working order.

I can apply test them now and i'll get back with the results.

Quote:
Originally Posted by snowman_al View Post
Can you clarify a couple of things please?
Is it one or both speakers with the 'sparking' noise?
You say it / they make a noise when not playing music sometimes. Now you have the covers off can you watch the cones and see if they are moving in and out with nothing playing. Try different positions of the volume control too.
Do you have other speakers to try to make sure the amplifier or cables are not to blame?
I believe it's only both, but im not 100% too sure on this. I'll take the covers off again and put the volume up and watch, and I'll get back with the results from that too.

I don't have any other speakers, nor cable. Just the two that I bought originally.

Quote:
Originally Posted by Techman View Post
I've got a pair buried somewhere in the loft and I can tell you that they don't like a lot of "Quo" through them at high volume, even when powered by the original Dynatron system they came with, and are likely to make the noises you describe after such an event
I could also tell you that they don't seem to like a lot of Queen being played at a high volume either, which is unfortunate for them.
I would say that they sound quite decent, but I've never had another pair to compare them too.
Thank you all for your help, i'll get to testing now.

Thanks.
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Old 21st Jan 2019, 12:20 am   #23
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Default Re: Speaker noises

It turns out it is both speakers, but the left being much worse. The left pops and scratches, while the right just scratches with no music, and on full volume.

When I first turn the system on, it's the worst, lasting around 3 to 5 seconds, before dying down, just to do randomly do so with use, or just being powered on.

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Old 21st Jan 2019, 8:07 am   #24
Nuvistor
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Default Re: Speaker noises

With the description of those noises are you sure it’s the speakers and not two faulty amplifiers. With no drive, I.e, no music and full volume there should be virtually no signal being fed to the speakers to move the voice coils, perhaps just a small amount of noise (hiss).
Noisy volume controls could well produce those symptoms.
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Old 21st Jan 2019, 8:13 am   #25
snowman_al
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Default Re: Speaker noises

Now what happens if you swap the left and right speakers round?
Does the 'pops and scratches' sound move to the other speaker?

This will help identify if the problem is the speakers or an amplifier fault, poor switch contact or volume control etc..
Alan

PS, just re-reading your initial post about 2 different amplifiers. Can you do the same test again with the other amplifier too?

Last edited by snowman_al; 21st Jan 2019 at 8:25 am. Reason: PS
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Old 21st Jan 2019, 8:22 am   #26
crackle
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Default Re: Speaker noises

I think we need to establish if the cone is moving in and out freely with no rubbing and if the inner suspension is attached. The inner suspension cant really be checked without taking the speaker out of the cabinet and looking from the side of the speaker at the inner end of the diaphragm cone.
Move the diaphragm in and out to its full extension and see if the inner suspension comes away from the chassis.
At the same time listening for any scratching or rubbing noise.
I dont know the construction of these speaker drivers but I have seen a voice coil become loose on the coil former and slide on it, that would produce the type of noise you describe.
I am not too sure how you would test for that.

But if the speaker is OK then the problem is probably in the amplifier. Possible causes dirty/worn controls, dry joints, leaky/breaking down transistors or other components.

Mike
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Last edited by crackle; 21st Jan 2019 at 8:29 am.
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