I've just had a similar experience with a pre-loved Pfaff 2056 that I bought to take to quilt days. I also bought it for the IDT, not noise, but it's so quiet, often the girls don't think it's running when it is. One thing I didn't take into account prior to purchase was the weight and I almost wish I had now. It's very heavy. Maybe that's why it's so quiet? Nah, I've just got the absolute greatest tech at my local store!