Thiel Owners

I have been wondering if it would be possible to increase the impedence with 4 to 6 ohm if I were to refurbish the xo of my 3.5? My single ended otl amp would be more efficient at higher impedence.

I don't know if this is relevant to anyone here but Audio Consultants in Chicago was a Thiel dealer for decades.  They've usually got a few pairs of Thiels on their used list.  Right now 3.5, 2.2 and 2 for sale.  

Oblgny, thank you,
can you please ship USPS to a PO BOX?  it should be 14$ insured, this is the price I paid to send mine to Mr Gillum for the eq. Let me know if you are fine with it and how I can pay you and I’ll send the address.
Thank you again,

Regarding impedance, it is what it is. The designer chooses the nominal impedance for fundamental reasons and then optimizes all parameters around those dirver particulars. In particular, Jim needed low inductance drivers for high-end extension and low distortion, which is determined principally by voice coil turn count. Jim believed that if amp designers took their work as seriously as he took his, they would make amps that did their job of doubling their power into halved impedance loads to 2 ohms.

I have expressed a differing opinion here previously. IF the nominal impedance could have been 6 with minimum 4 ohms, the voltage sensitivity would be lower, but more amps could drive the load well. But, that's a big IF, because the laws of physics can not be suspended. So, we have 4 ohm speakers to contend with and the amplifier choice is of fundamental relevance to system performance. 

For the Record: Audio Consultants in the Chicago area was indeed as good a dealer as a manufacturer could ask for. Count on them for straight dealing. In those days of knowledgeable brick and mortar dealers, such questions of system pitfalls and synergy were a big part of the dealers' function. Nobody would be sold an anemic amp with a Thiel speaker and dissatisfaction and driver failures were a rare occurrence.