Peerless K040 Mids in Nightingale NM-1’s - UK Vintage Radio Repair and Restoration Discussion Forum

novicerepairer · 30th Jan 2023, 6:55 pm

Hi,
I have just bought a pair of Nightingale NM-1’s , but unfortunately, the Mids' foam is in poor condition.
Does anyone know how I can repair these to keep the original look and sound, or are they beyond repair?
If so, where could I get the best replacements from.
(I have included a few pics of them)

Radio Wrangler · 30th Jan 2023, 7:40 pm

Quite fixable.

New surrounds and glue came from a firm in Holland.

Old surrounds removed very carefully by scalpel, and the ramains shaved off the cone very carefully... ditto from the basket flange.

I pierced the dustcap in three places (120 degree apart) around the inside of the voice coil former. Just three little holes large enough to insert three short pieces of tinned copper wire of a size found to fill the inner gap and thereby shim the voice coil in the centre of the gap. This holds everything centralised while you do the glueing and the glue cures.

Once you're happy the glue is cured, remove the three little wires and just put a small dab of the glue over each hole.

The wires and holes trick is an alternative to removing the dust caps and having to buy new ones. It's also safer from getting rubbish in the gap.

Net result seems perfect.

David

novicerepairer · 30th Jan 2023, 10:29 pm

Thanks David for your reply.
I can’t salvage the original then? I have heard of someone using uni-bond!
Also, if I did the replacement, can I not do without the holes and wire trick, as with no knowledge of speaker construction, I would be worried where to place them and not damage the coils, or be too far in to create the shim effect.
Colin,

Radio Wrangler · 30th Jan 2023, 11:14 pm

I wouldn't try to salvage the original surrounds.

Peerless K040 drivers are greatly sought after. The job takes patience and care, but is quite possible.

You really do have to shim the voice coils to hold the cones centred for glueing. If you do not, it's quite likely that it sets with the cones offset and the wire of the voice coil rubs on the pole-piece surrounding it, ruining the speaker.

Look at the very centre of the cone and you will see a slightly protruding tube. The cone is glued around the outside of this tube. Inside the tube there is a dark paper cap, bunging up the hole and keeping crap out. This is the dust cap.

In most speakers, the dust cap is bigger and goes right over the end of the tube (the voice coil former) and glues onto the cone. In most speakers, you cut off the dust cap so that you can shim the gap between the inner pole piece and the former tube with paper or card to hold the cone assembly centralised.

Theoretically, you could poke a few bits of wire in, but with the dust cap covering and going beyond the voice coil former, you can't see where to do it!

But the K040 isn't like this, it's easier. The dustcap is fitted INSIDE the coil former so you can see where the inside face of the former is. I made three little holes in the dustcap, right against the former inner face. roughly 1mm diameter. A drill bit held in my fingers was all needed. I then tried different wire diameters until I found one size where three bits fit easily into the holes and inwards for about an inch. With a knot tied in the outside end of the wire so no risk of anything falling irretrievably all the way in!

The units in my big transmission line speakers have now done about 4 years since I replaced the surrounds. They sound as they should, and there is nothing visible from new.

David

Diabolical Artificer · 31st Jan 2023, 8:00 am

You can salvage the foam with watered down PVA glue which is what I did before me & David replaced the surrounds. You can use bog roll or tissue paper to bridge gaps, just peel off a few layers. This will affect the sound but you won't notice it.

Re replacing surrounds on the KO40, I didn't bother shimming like David.

Andy.

novicerepairer · 31st Jan 2023, 11:22 am

Thanks for your replies.
Maybe I will try the tissue trick as a temporary fix, just so I can hear them until I order and get the surrounds.
Am I right David that they are from Audiofriends?
Also, could I use bent out paper clips, or does it need to specifically be the tin covered copper.
Also, how long do they need to be and how far should be pushed in?
Thanks all, Colin.

Radio Wrangler · 31st Jan 2023, 12:23 pm

Paper clips may be a bit too thick.

I just happened to have a variety of different gauges of wire handy. Copper being soft and non-magnetic won't attract to the polepiece and gouge the surface.

I didn't try any temporary repair as it just becomes more stuff to remove when doing the proper job, and modern adhesives can be harder to manage than old crumbly stuff.

I think it was audiofriends.

DAvid

Beobloke · 31st Jan 2023, 2:18 pm

Don't waste your time trying to extend the life of the existing surrounds. If it works, it will be a temporary solution at best and these are excellent speakers, so the drivers deserve a proper re-foam.

I always use these people - excellent quality products and great service.

https://speakerrepairshop.nl/en/

novicerepairer · 31st Jan 2023, 2:37 pm

Thanks all. Ok I will wait and do the job properly.
Is tinned copper wire easy to get hold of?

novicerepairer · 31st Jan 2023, 2:55 pm

Sorry one last question.
Is it best to undertake the repair still attached to the speaker, or remove it to work on?
Thanks, Colin.

RojDW48 · 31st Jan 2023, 3:48 pm

I suspect this is the firm David referred to - https://speakerrepairshop.nl/en/ - I have used them several times - including on a pair of Peerless mids. They should have the exact foams for the drivers - that makes a big difference - generic ones are much more difficult to get right.

I always remove the drivers from the enclosures and sit them on their magnets on a level surface - it helps maintain the speech coil geometry.

Radio Wrangler · 31st Jan 2023, 4:11 pm

It could have been them, all that's lodged in my head was the Netherlands. Andy may have better recall. The new surrounds were exactly the right ones.

The K040MRF have metal back chambers and don't open into the loudspeaker cabinetry, so while you could do the job with the driver in situ, it's a lot easier to have the unit out and on the bench. Be sure to be able to reconnect phased the same way, of course.

David

David

novicerepairer · 31st Jan 2023, 4:36 pm

Thanks all that’s great. Colin.

Beobloke · 31st Jan 2023, 4:37 pm

Here you are - Peerless KO40 replacement surround:

https://speakerrepairshop.nl/en/foam...-2674-10000028

ajgriff · 31st Jan 2023, 6:52 pm

Audiofriends & Speakerrepairshop are both based in the Netherlands and offer a wide range of speaker surrounds. Their websites are a mine of information with instructions and videos explaining how to go about repairs. As you will see there are different ways to centre voice coils. Well worth studying before diving in. As others have said don't waste your time patching up the existing surrounds.

Alan

novicerepairer · 31st Jan 2023, 7:26 pm

Thank you, could someone also advise the best and safest way of removing the old foam and glue.
Can I use alcohol, acetone for example, or just a sharp crafting knife.

Beobloke · 31st Jan 2023, 7:31 pm

I've always used a scalpel for removing the glue from the cone, a chisel for the stuff on the chassis and decent amounts of IPA (not the beer...) although Ambersil Label Remover is a recent discovery that does an even better job.

https://uk.rs-online.com/web/p/adhes...movers/4821277

ajgriff · 31st Jan 2023, 7:49 pm

Quote:

Originally Posted by Beobloke

..... Ambersil Label Remover is a recent discovery that does an even better job.

If I'm interpreting the safety data correctly Ambersil Label Remover is basically white spirit with orange essence added to disguise the odour. White spirit is brilliant for removing labels.

Alan

novicerepairer · 31st Jan 2023, 8:07 pm

Thanks so much.
I have found a local man ( David Smith ) that will do them for £40 each, with me to supplying the foams.
I must admit it has made me more nervous than I was, after speaking to him, but I think the cost is going to still push me to do myself and to be honest, I would like to gain the experience for possible future use.
Just would have liked it to have been some lesser quality drivers for my first attempt.

ajgriff · 31st Jan 2023, 8:34 pm

Quote:

Originally Posted by novicerepairer

Just would have liked it to have been some lesser quality drivers for my first attempt.

How about these for practising your skills:

https://www.vintage-radio.net/forum/...d.php?t=197942

You could always sell them on if your repairs are a success.

Alan

30th Jan 2023, 6:55 pm	#1
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Peerless K040 Mids in Nightingale NM-1’s Hi, I have just bought a pair of Nightingale NM-1’s , but unfortunately, the Mids' foam is in poor condition. Does anyone know how I can repair these to keep the original look and sound, or are they beyond repair? If so, where could I get the best replacements from. (I have included a few pics of them) Attached Thumbnails

30th Jan 2023, 7:40 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Peerless K040 Mids in Nightingale NM-1’s Quite fixable. New surrounds and glue came from a firm in Holland. Old surrounds removed very carefully by scalpel, and the ramains shaved off the cone very carefully... ditto from the basket flange. I pierced the dustcap in three places (120 degree apart) around the inside of the voice coil former. Just three little holes large enough to insert three short pieces of tinned copper wire of a size found to fill the inner gap and thereby shim the voice coil in the centre of the gap. This holds everything centralised while you do the glueing and the glue cures. Once you're happy the glue is cured, remove the three little wires and just put a small dab of the glue over each hole. The wires and holes trick is an alternative to removing the dust caps and having to buy new ones. It's also safer from getting rubbish in the gap. Net result seems perfect. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

30th Jan 2023, 10:29 pm	#3
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thanks David for your reply. I can’t salvage the original then? I have heard of someone using uni-bond! Also, if I did the replacement, can I not do without the holes and wire trick, as with no knowledge of speaker construction, I would be worried where to place them and not damage the coils, or be too far in to create the shim effect. Colin,

30th Jan 2023, 11:14 pm	#4
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Peerless K040 Mids in Nightingale NM-1’s I wouldn't try to salvage the original surrounds. Peerless K040 drivers are greatly sought after. The job takes patience and care, but is quite possible. You really do have to shim the voice coils to hold the cones centred for glueing. If you do not, it's quite likely that it sets with the cones offset and the wire of the voice coil rubs on the pole-piece surrounding it, ruining the speaker. Look at the very centre of the cone and you will see a slightly protruding tube. The cone is glued around the outside of this tube. Inside the tube there is a dark paper cap, bunging up the hole and keeping crap out. This is the dust cap. In most speakers, the dust cap is bigger and goes right over the end of the tube (the voice coil former) and glues onto the cone. In most speakers, you cut off the dust cap so that you can shim the gap between the inner pole piece and the former tube with paper or card to hold the cone assembly centralised. Theoretically, you could poke a few bits of wire in, but with the dust cap covering and going beyond the voice coil former, you can't see where to do it! But the K040 isn't like this, it's easier. The dustcap is fitted INSIDE the coil former so you can see where the inside face of the former is. I made three little holes in the dustcap, right against the former inner face. roughly 1mm diameter. A drill bit held in my fingers was all needed. I then tried different wire diameters until I found one size where three bits fit easily into the holes and inwards for about an inch. With a knot tied in the outside end of the wire so no risk of anything falling irretrievably all the way in! The units in my big transmission line speakers have now done about 4 years since I replaced the surrounds. They sound as they should, and there is nothing visible from new. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

31st Jan 2023, 8:00 am	#5
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Peerless K040 Mids in Nightingale NM-1’s You can salvage the foam with watered down PVA glue which is what I did before me & David replaced the surrounds. You can use bog roll or tissue paper to bridge gaps, just peel off a few layers. This will affect the sound but you won't notice it. Re replacing surrounds on the KO40, I didn't bother shimming like David. Andy. __________________ Curiosity hasn't killed this cat...so far.

31st Jan 2023, 11:22 am	#6
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thanks for your replies. Maybe I will try the tissue trick as a temporary fix, just so I can hear them until I order and get the surrounds. Am I right David that they are from Audiofriends? Also, could I use bent out paper clips, or does it need to specifically be the tin covered copper. Also, how long do they need to be and how far should be pushed in? Thanks all, Colin.

31st Jan 2023, 12:23 pm	#7
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Peerless K040 Mids in Nightingale NM-1’s Paper clips may be a bit too thick. I just happened to have a variety of different gauges of wire handy. Copper being soft and non-magnetic won't attract to the polepiece and gouge the surface. I didn't try any temporary repair as it just becomes more stuff to remove when doing the proper job, and modern adhesives can be harder to manage than old crumbly stuff. I think it was audiofriends. DAvid __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

31st Jan 2023, 2:18 pm	#8
Beobloke Heptode Join Date: Oct 2007 Location: Southampton, Hampshire, UK. Posts: 820	Re: Peerless K040 Mids in Nightingale NM-1’s Don't waste your time trying to extend the life of the existing surrounds. If it works, it will be a temporary solution at best and these are excellent speakers, so the drivers deserve a proper re-foam. I always use these people - excellent quality products and great service. https://speakerrepairshop.nl/en/

31st Jan 2023, 2:37 pm	#9
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thanks all. Ok I will wait and do the job properly. Is tinned copper wire easy to get hold of?

31st Jan 2023, 2:55 pm	#10
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Sorry one last question. Is it best to undertake the repair still attached to the speaker, or remove it to work on? Thanks, Colin.

31st Jan 2023, 3:48 pm	#11
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	Re: Peerless K040 Mids in Nightingale NM-1’s I suspect this is the firm David referred to - https://speakerrepairshop.nl/en/ - I have used them several times - including on a pair of Peerless mids. They should have the exact foams for the drivers - that makes a big difference - generic ones are much more difficult to get right. I always remove the drivers from the enclosures and sit them on their magnets on a level surface - it helps maintain the speech coil geometry. __________________ '....don't go mistaking Paradise for that home across the road!' (Bob Dylan)

31st Jan 2023, 4:11 pm	#12
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Peerless K040 Mids in Nightingale NM-1’s It could have been them, all that's lodged in my head was the Netherlands. Andy may have better recall. The new surrounds were exactly the right ones. The K040MRF have metal back chambers and don't open into the loudspeaker cabinetry, so while you could do the job with the driver in situ, it's a lot easier to have the unit out and on the bench. Be sure to be able to reconnect phased the same way, of course. David David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

31st Jan 2023, 4:36 pm	#13
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thanks all that’s great. Colin.

31st Jan 2023, 4:37 pm	#14
Beobloke Heptode Join Date: Oct 2007 Location: Southampton, Hampshire, UK. Posts: 820	Re: Peerless K040 Mids in Nightingale NM-1’s Here you are - Peerless KO40 replacement surround: https://speakerrepairshop.nl/en/foam...-2674-10000028

31st Jan 2023, 6:52 pm	#15
ajgriff Nonode Join Date: May 2004 Location: Halifax, West Yorkshire, UK. Posts: 2,587	Re: Peerless K040 Mids in Nightingale NM-1’s Audiofriends & Speakerrepairshop are both based in the Netherlands and offer a wide range of speaker surrounds. Their websites are a mine of information with instructions and videos explaining how to go about repairs. As you will see there are different ways to centre voice coils. Well worth studying before diving in. As others have said don't waste your time patching up the existing surrounds. Alan

31st Jan 2023, 7:26 pm	#16
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thank you, could someone also advise the best and safest way of removing the old foam and glue. Can I use alcohol, acetone for example, or just a sharp crafting knife.

31st Jan 2023, 7:31 pm	#17
Beobloke Heptode Join Date: Oct 2007 Location: Southampton, Hampshire, UK. Posts: 820	Re: Peerless K040 Mids in Nightingale NM-1’s I've always used a scalpel for removing the glue from the cone, a chisel for the stuff on the chassis and decent amounts of IPA (not the beer...) although Ambersil Label Remover is a recent discovery that does an even better job. https://uk.rs-online.com/web/p/adhes...movers/4821277

31st Jan 2023, 8:07 pm	#19
novicerepairer Tetrode Join Date: Jun 2020 Location: Basildon, Essex, UK. Posts: 94	Re: Peerless K040 Mids in Nightingale NM-1’s Thanks so much. I have found a local man ( David Smith ) that will do them for £40 each, with me to supplying the foams. I must admit it has made me more nervous than I was, after speaking to him, but I think the cost is going to still push me to do myself and to be honest, I would like to gain the experience for possible future use. Just would have liked it to have been some lesser quality drivers for my first attempt.