The best ones can be beautiful and well-crafted instruments with a powerful tone, with the 1920s and until about 1933 generally regarded as the most sought-after period. Roth violins were played and praised by distinguished artists of the day such as Eugène Ysaÿe, Henri Marteau and Mischa Mischakoff. As mentioned above, it is generally understood these days that the top instruments were made predominantly by Ernst Heinrich Roth himself (especially those hand-signed by Roth). They were usually copies after Cremonese models of the early 18th century, among which the Stradivari and Guarneri del Gesù ones are considered to be the most accomplished (although there exist some beautiful copies of Amati and Ruggieri). These top instruments stand out by the exceptional quality of their wood (with very fine-grained Italian spruce on top and a highly flamed maple back), their glowing oil varnish (frequently an attractive red-brown on a warm, golden ground) and their beautifully finished f-holes. These attributes, together with a powerful, rich and mellow yet focused tone with bright, carrying overtones, have secured top Roth instruments a reputation as excellent orchestral and solo instruments. They are also increasingly sought after for their investment value (current auction record: US $17,250 for a Roth cello / Tarisio New York, November 2005).