I thought I'd bump this thread as the video is always worth a watch
I managed to get my hands on Geoff Black's 1960s Ed Presnell 3 string at the weekend while at Launde. It is a great example of a traditionalAppalachian dulcimer and I used it to highlight some of the differences between older dulcimers and contemporary instruments during my talk on older playing styles. The instrument is long scale, the headstock and fretboard are all one piece (now that's a construction feature I liked !), the action was high enough to hang your washing off and the fret pattern was around 1/4 tone sharp all the way. If I hadn't seen and heard Nettie playing in the video here I would have been at a loss as to what to do with the instrument because it will not play in tune with a 'standard' approach. However, winding the melody string up to 'b 1/2' and middle string up to around c then dropping the bass to C and the instrument started to perform. Nettie played from a 1'-1-1 tuning (or 1'-1-1 flatin this case!), centering around the 7th fret (the mixolidian scale). I've not heard her use the open string in the 5 recordings of her playing I have found, which is possibly why the Presnell scale being so far out at the open string just was never an issue. When I played with a noter and a Presnell wood strummer the instrument wasvery, veryloud and had an incredible tone - just magic I'm hoping to get together with Geoff shortly and record the instrument in Nettie's playing style. This dulcimer was certainly not an instrument for the faint hearted and it seemed to be another example of a pre-revival dulcimer build primarily with one tuning and one playing style in mind.