Plastic Yamaha JA5002

Ns-20

Hello from France.
The first time I post here.

I bought a pair of NS-20 this summer. Greats speakers :music:

JA-5002 (as full range ?)
JA-2053 as medium
JA-0505 as tweeter (not present and replaced by one Audax.)

Because the TW Audax was too low in sensibility, I have replaced by Fostex FT50H.

Pictures (with Audax.)
 

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This is the data about JA-5002

Voice coil 66mm dia alminium edge wound voice coil
Alnico magnet
impeadance 8 ohm
f0 : 35Hz
efficiensy : 92dB/w/m
f-range : 35Hz~6kHz
size : W500×H680×D110(mm)
 
Hello Mambo,

Thanks for PM.

I have a pair of NS-20.

Thanks for data about JA-5002. It's difficult to find.


I'm surprised by the efficiency 92 db for JA-5002.
I found (on audio-heritage) 102 db for NS-20.

Must I understand this is the association of JA-5002 + JA-2053 giving very good efficiency to the speaker ?
 
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efficiency

hi René,

There are confusing change was happened New JIS and Old JIS.
(JIS : Japanese industrial standard)

may be the 92 or 95dB was masured by old JIS but speaker system was measured by New JIS.

normally it shall be 95 or 96 dB is acceptable.
Efficiency is almost decided by Midrange JA-2053.
It was developed for Electric organ first , so efficiency is the result of mid range driver.

Latter model NS-30, NS-370 it was used JA-3953, it was exelent transducer
as much as JBL D-131.

best Regards,
Mambo
 
speaker setting
I have one thing to tell everyone who have Plastic YAMAHA.

Please put your speaker at least 1m away from the wall.
You can decide evaluating the distance between speaker and the walls

If there are no space then, Please put the reflector aslant, back of a speaker .

Bass will be better than close layout.

best mambo
 
Hi everybody,

I use NS-20 at 80cm / 1m from the wall. Not far from the corners of the room.
Bass are good and really fast. Very good mediums and I must find the best adjustment for the tweeter.

Efficiency is great. I don't need big power to obtain a good strong level. It's almost impossible to give 1W to these loudspeakers (if you have modest room and neighbour.)
For example, my Tannoy (HPD315A) are a lot less efficient (92,5db in theory.)

It always difficult to compare an open back with another conventional speaker.

Perhaps later I'll try to put JA-5002 and JA-2053 on the same baffle (open baffle with little side panels.)


Mambo,

Do you think it's possible to find response curves for JA-2053 and JA-5002 ?

Thank you !
:music:
 
Freq res curve

Hi Rene

It is hard for me to find out the published items
the transducers in the speaker system never published.

BUT now you can check them at your House , If you have iPod toutch or iPhone.

download speaker analyzer(some aprication are free) and measure real your speakers.

Best Regards,

Mambo:banana:
 
Hi all ...
Stumbled across this..
tx for all the info.

Picked up a pair of NS330 this weekend and hooked them up to my DIY 2a3 set amp...

I prefer them really far from the back wall at about 2m and very close to each other toed in quite a bit...

I have to ask why these are not so highly regarded as this must be one of the best sounding speakers I've had...
certainly the best OB as well(comparing to some of my DIY's)
Actually I am so happy people have not caught on to these as much as the Altec 755a and Goodmans axiom 80 cause I am certain the prices will sky ....

I am hoping to connect it up to the awesome Sansui AU 111 one of these days as I just have a gut feel that it will be a great synergy....

These things are so musical with the 2a3 set I can say it's like listening to a good ESL 57 with bass...

And the best part is I found a good condition pair for well... the price of some of my snake oil interconnects...
IMG_0513.JPG
 
Hi Guys,

I hit a jackpot when an owner decided to sell his rare Yamaha NS-250E to me.

My driver is JA3501E and Horn tweeter is JA0506. One question have anyone of you changed the crossover capacitor?

Im thinking to replace the capacitors but I've no idea what caps are this. Anyone any idea?

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