I run a Dynaco PAS-3X in my 'second' system (McIntosh 250 / Dynaco PAS / Dynaco AF-6 tuner / KEF Q60 speakers / Panasonic linear turntable and Pioneer CD player). The PAS is a very pleasant preamplifier and with a SDS Power Supply board, new coupling capacitors and tone control bypass it does a competent job. As mentioned above, it isn't exactly the most detailed or revealing preamplifer, but it is very musical. Perfect for less-than-stellar recordings and less than perfect audio systems.
They do have a high output impedance and work better with an amplifier of higher input impedance.
They do have a high output impedance and work better with an amplifier of higher input impedance.