Interesting results and I realize that your experiment was from the OHM's point of view. I have been experimenting with various tube types, but from the Prima Luna's point of view. I have owned the Prima Luna PL2 and PL5 for 3 years and have spent the better part of the last year experimenting on the PL5 with different tube types. What prompted this experimenting was the upgrading of my speakers from Acoustic Research 302 (3 way, 10 inch woofer, acoustic suspension) to Opera Platea floorstanders (2 way, 6 inch woofer, front ported). The other PL5 associated equipment is a Musical Fidelity CD PRE 24 (ss preamp/cd player) and a SONY SCD 555ES SACD player.
The output tube types tried were KT 88 (Svetlana Winged C), 6550 (Svetlana Winged C), EL 34 (Electro Harmonix), and KT 90 (Electro Harmonix). The speakers were tried only from the 4 ohm tap. Each tube type was used for at least 2 months.
I found the KT 90's fairly sterile sounding and not very engaging. All types of music sounded pretty lifeless. I wasn't expecting this result.
I felt that the music was the most dynamic sounding with the KT88's, only slightly less so with the 6550's. There was more than sufficient detail, but the music was not particularly sweet sounding. What was strange, was that both tube types didn't seem to last very long ... a few hundred hours at most. There was no particular pattern to it, the tubes would just seem to get excessively scratchy and noisy.
The EH EL 34's have become the keepers. The sound is dynamic, lively, and sweet. All ends of the spectrum are reproduced with good detail. The tubes seem to be lasting the longest.
Anxious to see your next post. I plan to try this experimenting with the PL2 next.
Regards,
Rich
The output tube types tried were KT 88 (Svetlana Winged C), 6550 (Svetlana Winged C), EL 34 (Electro Harmonix), and KT 90 (Electro Harmonix). The speakers were tried only from the 4 ohm tap. Each tube type was used for at least 2 months.
I found the KT 90's fairly sterile sounding and not very engaging. All types of music sounded pretty lifeless. I wasn't expecting this result.
I felt that the music was the most dynamic sounding with the KT88's, only slightly less so with the 6550's. There was more than sufficient detail, but the music was not particularly sweet sounding. What was strange, was that both tube types didn't seem to last very long ... a few hundred hours at most. There was no particular pattern to it, the tubes would just seem to get excessively scratchy and noisy.
The EH EL 34's have become the keepers. The sound is dynamic, lively, and sweet. All ends of the spectrum are reproduced with good detail. The tubes seem to be lasting the longest.
Anxious to see your next post. I plan to try this experimenting with the PL2 next.
Regards,
Rich