Conservatory students often received instrumental instruction in group classes. Phillips described why this was necessary when he described the Leipzig Conservatory: "All subjects, including instrumental performance, were taught in classes, a procedure which was mandatory, if the logistical and financial demands of the new educational venture were to be met."
Lowell Mason, a well-known music educator from the United States, described instrumental classes he observed at the Leipzig Conservatory in 1852:
Objections have been made to the system of instruction in classes at the Leipzig Conservatory, but these are applicable to other studies as well as music. To be sure, where a pupil in a private lesson receives the undivided attention of his instructor for the space of an hour, in the class he receives only a fraction of the same. But this comparatively trifling evil is more than counterbalanced by the advantages as we have hinted above. The pupil becomes acquainted with many different styles, sees the beauties and faults of each, and is imperceptibly led in this way to the formation of his own. Again, by being constantly compelled to perform before others, he cannot fail to acquire a degree of confidence, which is beneficial and necessary to every public performer.
Conservatories in the United States patterned their instrumental instruction after the Leipzig Conservatory. The following description in the Oberlin Conservatory catalogue explains their use of instrumental classes:
Those who secure their education by means of private lessons alone, know little of the difficulties to be conquered, which lie outside of their own individual experience; and when they come to impart instruction themselves, they are met, perhaps at the very outset, with difficulties which they never noticed, and know not how to overcome. Pupils often see defects in a classmate which they do not find in themselves, and are thus enabled to see how the teacher manages and corrects them; so that when, in after years, the same difficulties are seen in their own pupils, they are not at a loss to know how to deal with them.
An 1871 bulletin from the New England Conservatory also described how the class method of instruction was an integral part of their instructional program:
Mendelssohn, whose judgment in musical matters none will question, says, 'By the participation of several in the same lessons and in the same studies, a true musical feeling is awakened and kept fresh among the pupils; it promotes industry, and spurs on to emulation; it is a preservative against one sidedness of education and taste,-- a tendency against which every artist, even in the student years, should be upon his guard. Upon the principle here advanced, is based what is now known as the Conservatory system of instruction. The great music schools of Leipsic [sic], Prague, and Paris, and other important centres of the science, owe their success, in large measure , to this system, and for the reasons that by it the best instruction is made available to the greatest number, and the greatest proficiency acquired on the part of the pupil in the shortest space of time.
The conservatory system of class instruction was the precursor to a form of violin instruction still commonly used today: master classes. Sollinger described the relationship between early conservatory classes and modern master classes:
Today, from time to time, master classes are held by artist teachers in which a group of advanced students is instructed by a teacher or performer who has achieved an outstanding reputation. This is a remainder of the conservatory system of graded classes in which students were carefully classified according to achievement and divided into any number of classes from preparatory to advanced. Different professors taught each level for varying tuition fees; the lowest grade was cheapest and the highest was the most expensive. The master teacher, who headed the department and dictated teaching methods, accepted only the most advanced students in to his master class-from which we get our modern term.