KT150 to KT120..or KT120 to KT150

[Initial burn-in matters on these tubes].  I underestimated this on the first try.  

KT150s:

AFTER 200hrs of play, I now consider the KT150 as a sort of a  "do no harm" output tube in my mono block amplifiers. Brand new, I did not like them very much.  Way better after 200-300hrs.  I had been comparing back and forth with my audio local dealer too in the same amps. Top end smoothed more at 300hrs, wearing in.   

KT120s:

In similar fashion, I did not like them brand new in the first 24-48hrs.  In fact, I passed over them too quickly jumping to KT150s prematurely. Missing velvety texture, tone, gave them another shot and super glad I did. At 72hrs+ started showing some hope with a tad rolled off highs/lows. Nice though. Easy listening.    

[Interconnect type pairing between these two output tubes] can help fine tone too.

If you trying both of these types of OTs, and you are looking for fine tuning of tone and prefer a good balance half way between ultra clear and rich tones, here are two combinations I landed on with interconnects after a few hundred hours of comparative testing fwiw. I don’t run silver over copper interconnects any more except with EL34 output tubes. This is only referring to KT120 vs. KT150s in neutral sounding amplifiers. Your results may vary of course.  Happy listening. 

KT150 / OFC ICs:

• Paired with OFC Oxygen Free Copper interconnects

KT120 / OCC ICs:

• Paired with OCC Ohno Continuous Copper Casting interconnects

@decooney   Intersting point. I tend to agree that ic's can make or break your system, depending on a number of variables. Your findings above do not actually jive with mine, as I am very impressed with a pair of OCC Ohno Continuous ic's with my KT150's. However, I am fairly sure that the design and make has a lot to do with the ultimate results. So, no real generalizations are possible here. 

daveyf OP

@decooney Intersting point. I tend to agree that ic’s can make or break your system, depending on a number of variables. Your findings above do not actually jive with mine, as I am very impressed with a pair of OCC Ohno Continuous ic’s with my KT150’s. However, I am fairly sure that the design and make has a lot to do with the ultimate results. So, no real generalizations are possible here.

Sure, and referring to tone changes mostly in a specific case example as an approach. No debate on whether OCCs work well or not with KT150s. All preference. In fact, I’m running Analysis Plus Crystal OCC cables at my source to preamp, preamp to amps right now with (KT120s or KT150s). Also, validated with five different pairs of Cardas Audio interconnect cables too up and down the line, in a similar manner. If I change to the exact same design cables in OFC Copper, it offers a slightly richer tone at the cost of slight loss of upper most frequency detail.  Something else to try in general terms with tube comparisons, if interested.

@daveyf my KT150s are back in their boxes, nice, yet kept comparing. After the KT120s had 100-200hrs on them, have not wanted to remove them. My first impressions were off for sure, and they just needed time to settle in. Very nice.