JPW ML 910 Speakers Restoration Project

[tiger0691]

On OXL I found an old speakers.
It was JPW floor stander, Model - JPW ML910 sold $ 2,250 in 1992.
3 Ways Loudspeaker System
Nominal Impedance 6 Ohms
Power Handling 120 Watts
Sensitivity 91 dB/Watt

Seller wanted Rs. 2,500.

When I checked the condition, it was too bad.
Baffle was swollen by moisture in a basement for a long time.
The enclosure was useless. All the units were in bad shape.
However I paid Rs. 1,000 to remake the enclosure.

After bringing them to my house, I have examined them.
These are health checkup report.

1. Sound are coming from both speakers.


2. Twitters would be changed.(One is dead)

3. Mid range speakers are good enough.

4. Mid Woofer are so so. (One is OK but the other one is bad)

5. Enclosure are for the funeral service (I need its diagram to remake with new wood)


6. Network are good enough

7. Binding Post are to be replaced

With minimum money, now the restoration project begins.
I need your kind advice and suggestions for better sound.

 

[reubensm]

OMG!! I have never ever seen speakers in such poor condition. From its present state, I guess you'll have to do a complete rebuild. The issue with taking this approach is that the speaker will never sound like how it was intended to, by the factory (also you'd not be able to souce exact replacement drivers and may have to settle for local replcament options)

Minimum money - well this is not going to be too kind on the wallet.

 

[tiger0691]

OMG!! I have never ever seen speakers in such poor condition. From its present state, I guess you'll have to do a complete rebuild. The issue with taking this approach is that the speaker will never sound like how it was intended to, by the factory (also you'd not be able to souce exact replacement drivers and may have to settle for local replcament options)

Minimum money - well this is not going to be too kind on the wallet.

I have similar twitters and found the original unit (Peerless M16NH 185mm hifi bass speaker woofers) in ebay.com.

Funny thing is that the speakers(except twitter) are still giving me a sound which is not bad.

 

[reubensm]

I have similar twitters and found Peerless M16NH 185mm hifi bass speaker woofers in ebay.com.

Funny thing is that the speakers are still giving me a sound which is not bad.

If the cones are good, the dust caps can be fixed. I once rebuilt a Technics speaker pair which had suffered terrible baffle damage during shipping. Had the enclosures completely rebuilt. But the drivers and crossovers were in repairable condition. The project costed me about 4.5K overall.

Here are the pics: http://www.hifivision.com/my-audio-...ur-audio-video-setup-here-171.html#post551481

 

[reubensm]

If these are very expensive speakers, why don't you try and restore them to their original condition with original spares? This is how they are intended to look:

 

[tiger0691]

If these are very expensive speakers, why don't you try and restore them to their original condition with original spares? This is how they are intended to look:

It looks so beautiful!

I wonder whether the same size of new enclosure could give me good sound or not.
If it is successful, I go for original units.

 

[tiger0691]

Enclosure rebuilding

Old speaker box is useful only to measure the size.

1 inch baffle became 2 inch due to moisture

I have found 30 years well dried ply wood (it was from a furniture) and a carpenter.

 

[tiger0691]

The 2nd Day of work.

 

[mpw]

tiger,

looks like you know the bylanes of delhi like the back of your hand

i wonder what you plan to do about those drivers ( IMO.. you will need to change all the 3 and the crossover ?? )

basically you will be making a new speaker itself as there will be nothing left of the old speaker.

but i think if you can find the time to do what you are doing, it should be a fun learning experience.

hope the DIY'ers on this forum pass by this thread to help.

mpw

 

[tiger0691]

tiger,

looks like you know the bylanes of delhi like the back of your hand

i wonder what you plan to do about those drivers ( IMO.. you will need to change all the 3 and the crossover ?? )

basically you will be making a new speaker itself as there will be nothing left of the old speaker.

but i think if you can find the time to do what you are doing, it should be a fun learning experience.

hope the DIY'ers on this forum pass by this thread to help.

mpw

Thank you for your advice.

These are my plan.

First, I will make the speaker box. (Now going on)

Second, I will put the units in the speaker boxes except twitters since it give me a good sound. Network also was working well when I tested.

Third, if it gives good sound, I will buy the original units on ebay.

Give me a better solution please.

 

[reubensm]

great going, can't wait to see the end result

 

[Audio_Freek]

Thank you for your advice.

These are my plan.

First, I will make the speaker box. (Now going on)

Second, I will put the units in the speaker boxes except twitters since it give me a good sound. Network also was working well when I tested.

Third, if it gives good sound, I will buy the original units on ebay.

Give me a better solution please.

Sir, Hats-off for your attempt in restoring almost dying speaker.

I have even cried once looking at a condition of AR speakers at my Home town,which was used as chair at a shop.

Recently i got a Technics speaker without shape-cabinets i spent a weekend restoring them and after restoring they were sounding great and enjoyed a lot.happy for bring back them to shape and sound

Awaiting for the update and progress.

 

[tiger0691]

Broken Network Repairing
One was good but the other was in bad condition.

Fixing with quick fix

Box rebuilding (Half Done)

Before and after

 

[krell]

great.i wish you will get your desired result

 

[tiger0691]

Speaker Boxes are almost ready.
Carpentering is done.
Tomorrow, there would be a painting.
Front and top are teak wood color.
It looks good but total black look is the plan.

 

[reubensm]

great progress, can't wait to see the finished product and hear your comments on how it sounds.

 

[tiger0691]

great progress, can't wait to see the finished product and hear your comments on how it sounds.

Internal size of boxes are same as original.
Wood material are thicker and heavier than the original.
Only twitter are changed. It can be adjusted by cotton tuning.
Tonight I would fit drivers.

 

[tiger0691]

Twitter in place of old one

Before fitting drivers

Connecting with amp.......

Sound are coming from all units.

Now I going to start tuning and aging.


Grill are needed to cover the ugly face of units.

 

[Hiten]

Nice work tiger0691. If you are willing to take little risk, you can slowly and steadily with little patience, lift the caved in dust caps with strong adhesive tape (but not so strong that dust cap comes out). Place tape only on dust cap apply little pressure with small paint brush, try to lift it slowly.
Regards

 

[madman29]

Fantastic project to try. Do tell us how it sounds. :clapping: