The 'guts' of all three seemed very similar with the exception of the small bell on the imp, so the difference seemed to be leadpipe/receiver. I measured them as accurately as I could with a tape and was astounded by the difference. The distance from where the pipe enters the valve block to the mouthpiece side of the first joint/ knuckle was a consistent 14-15mm on all three, and the receivers were all 63-64mm long. The overall measurements from valve block to (mouthpiece) end of receiver varied greatly. The imp was 230mm, one sovereign was 250mm, and the other 265mm. I'm not even sure how these instruments are the same pitch, but they are - albeit with very different Intonation between the various harmonics. The longest leadpipe seems to be the most free blowing but also with the wildest intonation.
I'm wondering if anyone has any ideas as to whether the variation - particularly among the two sovs is due to ongoing development of the leadpipe design, or just within the accepted parameters of B&H manufacturing differences of that era?
Also, the long leadpipe instrument is excellent in all respects except for intonation - does anyone think there would be anything to be gained by shortening the lp by any amount in this respect?
I'm asking as I'm aware we have a few euph players with engineering credentials, as well as some knowledge about the changes taking place in the designs of this era - I'd be interested to hear what others think.
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