Válvula PY81 = 17Z3 Tenho outras veja a lista:3A4, 3BZ6, 3CY5, 4BL8, 4CB6, 5AM8, 5AQ5, 5CG8, 5U8, 5Y3, 6AJ8, 6AL5, 6AM8, 6BE6, 6BK7, 6BQ5, 6BR8, 6BS8, 6BW8 6BY8, 6BZ6, 6BZ7, 6CB6, 6CM7, 6CW5, 6DE6, 6ER5, 6FQ5, 6GK5, 6JC6, 6JC8, 6JT8, 6JV8, 6K4P, 6K7, 6KZ8, 6L6gc, 6LJ8, 6LN8, 6LT8, 6MD8, 6N2P, 6N5P 6N6P, 6N14P, 6SJ7, 6SN7, 6T8, 6U8, 6V6, 6X8, 7AU7, 8AW8, 8EM5, 8ZB6, 9JC8, 9U8, 10AL11, 10DE7, 11AR11, 12AU7, 12AV6, 12AX4, 12AX7, 17AX4, 12BA6, 12BE6, 12BH7, 12SA7, 12SK7, 14BR11, 17AX4, 17D4, 17DM4, 22AX4, 22DE4, 35W4, 50C5, 6082WB.EAA91, EABC80, EBF80, ECC83, ECC84, ECF82, ECF86, ECH81, ECH83, ECL80, EF5, EF41, EF183, EF184, EL81, EL84, EL86, EM83, EM87, EY87, HBC91, HF93, HK90, HL92, HY90, PCC84, PCC85, PCF82, PL83, PL509, PY82, XCC82, XCF82, XCL82, XCL84, XCL85, XF183, XF184.