Autoformer vs Speaker impedance Curve


Autoformers vs speakers with wild impedance curve swings (for instance; MC601 amp paired with B&W 802D3 speakers).

There’s a wealth of information about tube amp audio transformers interaction with speaker impedance, but I can’t find anything regarding Autoformer and speaker impedance/phase curve relationships. 

Can any techies enlighten me? 

Thanks!

(I tacked a similar post onto the end of a 10 year old thread but thought I might get a few more hits with a new thread.  Sorry for the redundancy)



73max
08-17-2018 11:41am@73max

Your B&W 802 D3 will be better off driven by a pair of Classe Delta CAM-300 monoblock amps or the CAM-600 monoblock amps.
+1 This is what I meant by the right amp  73max OP

Cheers george
Thanks George.  I’ve actually read that.

My confusion stems from the fact that some posts imply that autoformers help with a difficult load.   This would seem to imply they would be a good match for the 802D3s.   If, in fact, autoformers function similar to an  output transformer, the opossite would seem to be true.

I suppose it depends  how one defines a  difficult load.  Are these posts just considering the nominal impedance and the sensitivity,  ignoring the importance of impedance curve and phase issues??? Much yet to consider.
My confusion stems from the fact that some posts imply that autoformers help
Very simple Max.

Yes they do "help" with amps that can't drive those loads.
Best is to get the right amp that will drive them.
Not to put a band-aid on ones that can't.

Cheers George 
When considering an amp for my Magnepan 3.7 I contacted the factory and a large dealer and both said the autoformer would not make a good match with the Maggie's and that I would need at least 500 watts to even consider a Mc.