Finding (calculating?) speaker and amp impedance


I'm starting to understand why speakers with high efficiency and perhaps more importantly a flat impedance curve work well with tube amps.

If not published by the vendor/manufacturer, is there a way to determine the impedance curve from the specs that are provided?

Also, I have a pair of Magnepans that need high current amplification.

Is there a way to determine the current of an amplifier from vendor/manufacturer provided specs?

Thanks everyone!

hleeid

@chocaholic 

I have a Sansui AU-20000 that will not come out of protection mode.  I've been told it is essentially a boat anchor.  Used it for many years and really liked it, put it in a closet when the ARC amps appeared out of nowhere (wink).

Would you please share the repair shop who did your 717.  Thanks.

Regards,

barts

@barts I was referred to a gentleman on AudioKarma that specializes in vintage Sansui. He stripped boards, removed all old corrosive glue, completely recapped in addition to countless other parts, extensively tested, adjusted bias, burn-in, more measurements, etc…and kept me updated with details and photo’s throughout the process. He’s in a small town in Mississippi and prefers not to ship equipment. So, a 10 hour round trip for drop off and retrieval from here. 
 

Bottom line, it’s more of a hobby for him than a business. I’d want to check with him before passing his name along. 
 

@chocaholic 

Thanks...Mississippi is quite a drive for me, so that is out, but I am slightly confused due to you saying the 717 "it's in transit as I type this".  Does this gentleman sometimes ship and sometimes not?

Regards,

barts 

@barts Sorry…I should have been more clear. My wife went to visit her mom this weekend…about 2 hours from his location. She picked up my amp on her way. I married a good woman!

@chocaholic 

Thanks.  I married a good one also.  Music lover and doesn't give a hoot about $$ spent on audio.  In fact, she hears things and complains to me "that is not right!".

Regards,

barts