Preamps

georgehifi, ricred1,

Thanks for the information. But since the subs are self powered I don't see how the preamp output impedance can affect the sub. Also, the JL subs have a mic/calibration system, that would seem to me it would compensate for any possible low bass rolloff. Now, if having the sub connected affected the performance of the main amps then I would be concerned.

ozzy

But since the subs are self powered I don't see how the preamp output impedance can affect the sub.

The AR preamp with output coupling cap, has to drive not only your main amp input impedance, but also the 10kohm of your subs amp even though there are 2 outputs, and this could be the problem, the output cap in the AR  "may" not be big enough as explained in my last post, and cause a premature rolloff of the low frequencies, so the sub may not go down low enough.

Cheers George 

Vac

VAC is transformer coupled. 

ARC has a fact sheet on their website expressing concern about the tube preamps driving a main amp plus sub. it’s in black and white unless they pulled it. it killed a ref 6 deal for me.,