Looking for SUT for Air Tight PC-1 supreme


Has anyone try any SUT for Air Tight PC-1 Supreme?
With its rather low internal impedance, the only SUT I can think of that should work well with it is My Sonic SUT. I have Ortofon SPU T100 which is supposedly suitable for cartridge with internal imdedance of 1-6 ohm if I understand the spec properly. It sounds quite nice but am wondering if I can do better. Lyra Arion SUT did not work at all when I tried. I have no idea if Air Tight SUT is suitable but Air Tight top of the line preamp has My Sonic SUT built in.
Any suggestion or comment would be very much appreciated.
suteetat

Showing 2 responses by capnbob

Your Air Tight PC-1 has an output of .6mV with an internal impedance of 2.5 ohms, according the cartridge database. The problem is that it is a relatively high output voltage compared to the internal impedance. It depends on the overload voltage on your phono preamp as to how high you can boost the signal. Most phono stages overload at about 10 mV. So doing the math 10/0.6 = 1:17 is the highest step up ratio you can use. You can readily find 1:16 step ups, but they will give you a reflected impedance of 184 ohms. It should work fine, since the recommended loaded impedance is greater than 25 ohms. Impedance matching is not critical for SUTs, as long as the impedance load is not too low. Too high is ok. Some may recommend loading with resistors to make up the difference between the 184 ohms and the 25 ohms, but I personally find it is not necessary.
For .4mV with 1 ohm, the maximum ratio is 1:25, if your phono overloads at 10mV. With MC cartridges, a basic starting point is to use an impedance of 10 times the internal impedance to be safe. Therefore the recommended loading will be anything over 10 ohms. There are exceptions like with Denon where lower impedance loads tame the high frequency response. So you will definitely be safe with 1:25 or 1:20. You might be fine with 1:30, if your phono preamp can handle 12mV without overloading.