Depends on what mirrors you want to use.
5mm aperture and larger needs a notch filter which has to be tuned here at Pangolin with DT40 amps.
The best way to get C506's right now as a turn key system is to get a set with the Kvant amp if you want 3mm or 4mm aperture
Alex Hay makes a great amp to drive the 5mm, 8mm and 10mm sets as well. These need a notch filter which the Kvant does not have.
Both of these amps are compatible with our "AW50" coil configuration, which gives a bit better performance.
The DT40 systems have to use the standard/original coil configuration, while still good, can't be driven as hard as the AW50 scanners that the Kvant/Alex Hay drivers use.
Feel free to shoot me an email with any other questions!
Sincerely,
Ryan Smith
ScannerMAX Mechanical Engineer
ryan {at} scannermax.com