I have no Audio Voltmeter to speak of, so I ended up having to try both my o-scope and my DMM in-place of an actual Audio Voltmeter.  The measurements done with the DMM actually looked better than the results I saw using the o-scope to measure the AF out of the receiver.

I've posted a message on QRP-L.org to ask for comments on doing a MDS measurement with either a DMM or o-scope. Here is a copy of the that message: "I have a Tech 2465 o-scope and an Elenco M-2671Multimeter that I used for MDS testing of the receiver portion of the Willamette xcvr I am building. Using the o-scope proved somewhat of a challenge as the measurement down in the teens of millavolts at 600 to 800 Hertzx is somewhat hard to judge on the display. For the 3dB increase from noise floor to signal+noise floor, I was multipling the noise floor measurement by 1.41.

When I did the MDS measurement using the o-scope: noise floor was at 11mv, signal +noise floor was at 15.51 mv at -119dBm RF input to the receiver.  However, when I used the multimeter: noise floor was at 0.6mv, signal+noise floor was at 0.8 to 0.9mv with -130dBm RF input to the receiver.

I would like to say that my meter was more accurate and my MDS is really good, but I would like others to chime in and tell me what they think if they had to do MDS measurements without an audio voltmeter."

I would like anyone here who knows and has done MDS measurements to tell me where I stand. Thanks in advance!