Siemens EL 34

@pdreher I have a pair of Quicksilver KT Mono's with KT-150's on order... so I'm hoping they will scratch my itch and quell any regrets I may have in selling the RM9 MK2.

Thanks for making the correlation and for sharing this update. For one, the KT Monos will run cooler. These Monos should sound quieter, with a darker background.  One thing to note fwiw, KT150s in my QS amps took 200-300hrs to settle in, relax, whatever..before the tone I was looking for started showing up. Some people say they are more linear.  I wanted something closer to EL34s, so I removed the KT150s and now running KT120s, a little more rolled off on top. Will be interested in your assessment after 200hrs on the KT150s in your QS amps.  

@decooney  another benefit to the QS is I'll only be swapping out four power tubes vs. eight power tubes in the RM9 MK2.

Good to know I should expect a 200-300 hour break-in before the KT150's are settled in.  

FYI, there is a Quicksilver Audio group on face book and an EE audiophile there who used to work for QS about 30 yrs ago remarked this about his new KT monos:

KT Monos w KT170s is what I’ve been running for the last 5 months and I’m loving the match. One thing I can say is that you must experiment w bias level. It seems that the KT150s are more forgiving on bias setting. Surprisingly to me, the difference appears in the upper mids and highs and not the bass for the KT170s.

With high gain selected KT170s they can be run in the 60W Monos and that’s not such a great match. More listening to do, as always…

I'm liking the Tung Sol EL34B's that came with my Will Vincent ST-70 although I have nothing to compare them to - it's my first EL34 amp and I think I'm hooked on the EL34 sound.  Now if I could just forget about trying QS Mid-monos and be happy:)

@pehare KT Monos w KT170s is what I’ve been running for the last 5 months and I’m loving the match. One thing I can say is that you must experiment w bias level. It seems that the KT150s are more forgiving on bias setting. Surprisingly to me, the difference appears in the upper mids and highs and not the bass for the KT170s.

Agree with this, having done quite a bit of experimenting with my QS M120s adjusting manual bias with meters listening to KT120s and KT150s biased at 40, 45, 50, 55, 60ma per output tube. The mids and highs tend to open up with added clarity and expanded sound stage as bias gets bumped up.