The older generic "bench supplies" used to be linear - with a multi tap transformer in them. You can hear relays click as it switches taps as you increase or decrease the output voltage so the linear regulator doesn't need to burn as much power to regulate at the lower voltages. Sucks that the new ones are all switchers now...
I have older HP supplies, they are heavy, bulky, but damn quiet! All the imports are switching power supplies. BTW - Love the R&S Scope!
The older generic "bench supplies" used to be linear - with a multi tap transformer in them. You can hear relays click as it switches taps as you increase or decrease the output voltage so the linear regulator doesn't need to burn as much power to regulate at the lower voltages. Sucks that the new ones are all switchers now...
Please note: This test was run with and without the probes grounded and terminated, the noise was about the same regardless.