Yamaha Compression drivers

[JAMES@BOYD.ORG]

Hello all,
I've been trying to find some information about Yamaha compression drivers. Google comes up with very little this time.
I have seen the plots of a JA-6681 on the Azura horn and they are pretty spectacular.

I have chanced on a single JA6601 and i'd be very interested to know how it differs from the 81. - and if its worth looking for its pair..
Thanks in advance
james

[CV]

Hello James,
re: the plots - aren't they just!
I think the JA6681s may be rather different to the 6601, not that I'm familiar with it - can you post some pictures?

I reckon the key advantage of the 6681 is the unusual diaphragm suspension, see:
http://www.azurahorn.com/pages/Yam%2...0diaph_jpg.htm

with beryllium copper fingers - I reckon that really helps to lessen resonances caused by reflection at the dome-surround interface and is in part responsible for the amazing response plot on the 160.

The other thing is that the 160Hz horn may well match the internal flare rate of the 6681

Hope this is of use.
Best,
Chris

[JAMES@BOYD.ORG]

Interesting! The 6601 I have looks identical.

http://picasaweb.google.com/jbjbjbjbjb/YamahaJA6601

The diaphragm tests ok. Except for 2 tiny dings at the edge. I wonder if they will cause a problem.

I'll try it out in my 240hz lecleach this weekend. And see if I can emulate those plots!

Anyone got another? some hope...

also in the box was a single Pioneer PD-801. Again, very little comes up on google. Looks quite like a TAD 2001 to me. Which would make sense. Haven't been able to see the diaphragm yet as I don’t have an alan key with me.
Any experts on this one too?

cheers
james

[CV]

Hi James,
Very interesting! Looks the same, though I wonder about the 8 ohm impedance.

There's a chance I may have a spare 6681 available in the near future in which case I will keep you posted; please PM me about that and I will explain further...

Best,
Chris

[badman]

The ding probably won't matter enough to be audible. In an ideal world, of course, it wouldn't be there.

[JAMES@BOYD.ORG]

Chris,
Can't seem to email or IM you.
Could you email me (at me my user name email address)?
thanks
james

How do I get the administrator to allow me to PM? (nothing in the FAQs about this)

[bear]

Originally Posted by JAMES@BOYD.ORG

Interesting! The 6601 I have looks identical.

Picasa Web Albums - op.9 - yamaha JA6601

The diaphragm tests ok. Except for 2 tiny dings at the edge. I wonder if they will cause a problem.

I'll try it out in my 240hz lecleach this weekend. And see if I can emulate those plots!

cheers
james

Martin has some gentle EQ on the top end to flatten it on his horns.
It will be good to know what it does without EQ on the the L'Cs...

_-_-bear