Restoration of vintage speakers.

[captrajesh]

Not a tricky question at all. The performance is very easy to observe - does the system make music? Is it balanced to portray music realistically? Just listen, and you have your answer.

Beautifully said! Can't be simpler!!

the cloth surrounds needs an application of a rubberized coating to ensure the air does not leak out as it is acoustic suspension system designed by I think Henry Kloss . The result of the restoration was magical.

Kuruvilaji, could you elaborate what did you use for applying to surrounds? I've purchased some kind og goop that I've got from Vivek. It resembles fevicol in colour and consistency.

 

[Asit]

Hi SIDEWINDER18X,

Thanks for the interesting thread.

I have a pair of Canton Karat 60 speakers bought new in Germany in 1989. These are large bookshelf speakers (3-way bass reflex with a front port) with 10" woofers, 5" mid-woofers and 1" Aluminum-Manganese dome tweeters. The crossovers are at 450 Hz and at 4500 Hz. Frequency range is given as 22 - 30000 Hz, and sensitivity is high (93.4 dB with 1W at 1m). Nominal impedance is 4 Ohms and distortion is stated at less than 0.7%. In 1989, Canton was still a small speaker brand, and they developed all components of the speakers themselves and my speaker was completely hand-made with solid wood cabinet.

Over the years, I have changed/upgraded my sources and amps, but have stayed with my now 25 year old speakers. I guess the simple reason is, they are still working, and working well. There is no apparent sign of any degradation in terms of sonics. If anything, the sound has improved with better equipments upstream. A lot of people have visited my home and listened to my speakers, and according to most, if not all, the speakers are one of the main strengths of my system. The rest of my system is given in my signature.

I like the openness, tonality, cleanliness of the sound, and with good source material, the speakers just vanish. I have heard a lot of mid-range modern speakers including a few reasonably high end ones, but I do not quite get the sound I like and get from these speakers.

In the light of what you have written in the beginning post of this thread, I am starting to wonder what I can do in case the speakers start showing signs of illness. Since you are in Kolkata, I'd like to meet you and if you have time, may be you can visit my home and see the conditions of the speakers, and can offer your suggestions. These are quite big and heavy (about 17 kg each) for bookshelf speakers, and they are on stands which are even heavier (>20 kgs each). Hence it would be difficult to take them to your place.

Regards.

 

[GeorgeO]

Hi Asit

Here's my take:

Just because the speakers have aged doesnt mean they need attention-many vintage Altecs are still playing flawlessly decades after they were manufactured. OTOH speakers that have been neglected have deteriorated and need refurbishing. I refurbished one pair of 15 inch woofers by reconing and replaced the diaphragm on an HF unit and they are now preforming very well.

George

 

[kuruvilajacob]

Kuruvilaji, could you elaborate what did you use for applying to surrounds? I've purchased some kind og goop that I've got from Vivek. It resembles fevicol in colour and consistency.
__________________
Dear Captain,
I have used rubber latex as suggested by my speaker mechanic. He has used it for the surrounds of several such speakers. It seals the pores and will act as a coating at the same time does not make the surface hard. I use it once in a year to ensure the surrounds are sealed.

 

[kuruvilajacob]

I have been fortunate to have listened to Asit's amazing Canton speakers. They are truly great speakers. I remember him playing a live performance of a concert recorded by him in Germany on his Nakamichi 505. The imaging was wall to wall . I fully agree with Asit. Some of these vintage speakers are very difficult to be replaced by most of the new ones . I am also fully satisfied with my KLH model 5 which also disappears and gives superb imaging .

 

[ashar]

Any links for lightweight cones

 

[ashar]

Hello Everyone,
It's great to see people here who have deep passion and crave for vintage speakers. It's also very appreciable to see that how keen & particular they are on each and every aspect in selecting the accurate parts and precision to get them back to their original state or form.
In doing so you should always keep in mind some very important points if you want to get the job done accurately & correctly.

1. Re-magnetize the magnet before you recone.
Vintage speaker build around Alnico magnet will have a loss in their magnetic strength, even if they were not hard driven in any theater or in any pro installation or usage. This is due to aging and other circumstances. If you can measure gap strength with a gauss meter you will come to know about it for sure. So re-magnetizing is strongly recommended. Take a gauss reading before and after the process. You will see the difference.

2. Never coat or spray any lacquer or emulsion on the paper cone surface.
I see lots of misconceptions in this regards. Vintage speakers are built around Light, Soft and Felted cones. They are made as such for their unique tone. Its due to this they have a shorter life span.
Do not ever spray water proofing chemicals or doping lacquers on to the cone surface. It will alter the tonal characteristic of the speaker. Spaying any liquid will be absorbed by the cone pulp like a blotting paper. Hence the natural tone of the cones will change.

(But though there are several speakers of the past & present which do have treatment on them. Some for weather resistance, some for producing a unique tone out of them & some just for cosmetics such as "wet look".
The same formula cannot be applied for every speaker).
Vivek

Any links for light speaker cones as opposed to the local available ones which seems heavy, i need 8" and 6 " cones for my vintage Boltons 3 way came from cosmic covox .
Attaching a pic for reference thankyou.

 

[SIDEWINDER18X]

Any links for light speaker cones as opposed to the local available ones which seems heavy, i need 8" and 6 " cones for my vintage Boltons 3 way came from cosmic covox .
Attaching a pic for reference thankyou.

You should look out for cones from Shiva India or Jupiter India. They have some similar looking fixed edge, light weight full paper cone in 6 & 8 inch sizes.
With regards
Vivek