Over the past 10 years I have focused on Russian tubes from the era 1960-1980 and have discovered numerous types with very interesting characteristics. Signal tube like 6n6p, 6j51p, 6j9p, the high gain planar triode 6s17k, the strong, linear driver as 6e5p, power tubes like 6c4c, 6c33c, 6s18s and 4p1l. This last DH ( direct heated ) pentode has the reputation of amazing performance and low distortion in triode mode. After many days of breadboarding,…
By Enzo Grazioso