Originally Posted by el156
Hi All !
Does someone has used PCC189 for audio? These are variable mu twin triodes but i dont know if they usable for audio !
I have used them and I did not choose them at random. This is my story.
Several years ago I came across a article on the WWW. The question was posed “Is the 6dJ8 suitable for audio? Turns out someone had mislabeled Tunsgram variable mu valves as 6DJ8’s. The article was rather long winded. The short version is if the tube was biased toward the high end of the anode current scale it behaved as you would expect for a 6DJ8. At the 2, 3 & 4 ma anode currents it was very nonlinear.
The PCC189 is the 7 volt version of the imposter valve. I found a couple of dozen Tunsgram PCC189’s for near $1 each. A pair of them went into a common cathode line amplifier that made an Alesis RA 150 sound very Class A SET like. Another pair was biased up hot, I could not tell them from 6DJ8’s in that application. The fun was worth the few dollars.
All just for fun!