Thiel CS3 Without The EQ

The EQ's show up on e-bay every once in a while, figure roughly about $100-125. Even then I'd suggest you have it shipped to Thiel for an overhaul. If you were to go that route, I wouldn't let the worry of a few dollars of overpayment get in your way. These are old units and it might take several months for another to appear. Odd thing is they seem to show up in bunches, but, I wouldn't count on that. Furthermore, if there's a choice, consider spending more on the cleaner lookin one. FWIW, when Thiel still had new replacement EQ's for the 3.5's, they were asking $600 each for them.

Here might be a way to get the EQ and then some:
http://cgi.ebay.com/THIEL-CS3-FLOOR-STANDING-COHERENT-LOUDSPEAKERS-/260614994081?cmd=ViewItem&pt=Speakers_Subwoofers&hash=item3caddd38a1

I have no relationship with the seller and I am not endorsing the product for sale or the seller.

http://cgi.ebay.com/Thiel-CS-3-Electronic-Bass-Equalizer-/350368579288?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5193983ed8

With the EQ they are capable of outstanding bass, without not so much. Considering their age the 3's show up fairly often, especially on e-bay for very reasonable prices. Without the EQ I'd pass.

With the 3.5's you can cut the boost to 42 Hz, which can work quite well for use with sub-woofers. Of course if you can do without the sheer extra volume subs offer, the EQ'd sub-less bass is just as deep as most sub-woofers (and deeper than many).
Without EQ you'll need subs capable of working beyond "sub" up to about 70 Hz. Not an are where subs typically do their best work.