Por si es de interes y por eso de los "modelos", que aquí los clasifican en Grade A, B y C:

Grade A @ US$75,00/ea ; US$155,00/matched pair
Grade B @ US$65,00/ea ; US$135,00/matched pair
Grade C @ US$30,00/ea ; US$60,00/matched pair

Grade A - The best in the stock. Lowest noise and microphony with the tightest balanced sections we have available. This is typically 10% or often tighter given the large volumes of our stock.

Grade B - Low noise and microphonics with a section balance typically between 15% and 20%, but may be higher depending on available stock.

Grade C - Lowest noise but slightly microphonic. Section balance will be similar to Grade A or B. This grade is only suitable for use in the driver stage of an amplifier, or the output/buffer stage of a DAC or CD Player.

Si esto es cierto, como se puede comprar en páginas donde esto no se controla y luego va y te tocan las "C" y encima has pagado un pastón...



Saludos