sound from USB Parasound A-D unit drops

I have a new Parasound zphono usb preamp and digital interface which I'm using to rip my vinyl collection. When I first got the device my iMac (late 2012) was on Sierra and the device worked perfectly. When High Sierra was installed the problems started. The audio from the device would drop. First I checked with Audio Hijack support but they pointed to no input from the device. Next I tried a different USB cable for the unit but that made no difference. I contacted Parasound and they very nicely exchanged the device for another new one. I installed High Sierra 10.13.2 which has a fix for third-party USB audio devices. I could record 1 LP but then the problem of no audio coming into the system started again.

I don't believe there is a problem with the Parasound device. Their support has no reports of hardware problems. Seems the audio problems started with High Sierra and the latest fix does not work for my situation.

Would anyone have any insights into this problem?