Help with KT150 questions

Posted by daveyf (A) on April 13, 2020 at 18:32:18

My mono block tube amps use two KT150's per side. I need a matched pair for each mono block. The other day, I rolled into my amps a newish quad of KT150's and immediately heard a lessening of the SQ, although the amp seemed to play a lot brighter and in some ways more powerfully. My amps are self biasing. I took my quad of original KT150's ( with the amp manufacturer logo on them ) to my tech where we proceeded to try and test them on his tube tester, a Hickok. My tech noted that this tube tester cannot supply enough voltage to really get a total picture of what the KT150 under test is really doing, yet on three of the tubes that we tested, the transconductance was about the same, yet on the fourth tube, it was seemingly less?? What could have caused this?

So, I went home and was still quite unhappy with my newer tubes, so i rolled the original tubes back in (they have about 300 hours on them total)...and the SQ was definitely much better! Am i hurting the amp with the older tubes in place?

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Topic - Help with KT150 questions - daveyf 18:32:18 04/13/20 (22)

RE: Help with KT150 questions - Jonesy 09:56:58 04/15/20 (17)

RE: Help with KT150 questions - daveyf 13:03:57 04/15/20 (16)

RE: Help with KT150 questions - Jonesy 13:22:11 04/15/20 (15)

RE: Help with KT150 questions - daveyf 16:44:36 04/15/20 (14)

RE: Help with KT150 questions - Alex Kitic 00:38:07 04/21/20 (13)

RE: Help with KT150 questions - daveyf 00:53:56 04/21/20 (12)

RE: Help with KT150 questions - Alex Kitic 01:34:57 04/21/20 (11)

RE: Help with KT150 questions - Tre' 09:07:22 04/21/20 (10)

RE: Help with KT150 questions - daveyf 13:35:53 04/22/20 (1)

RE: Help with KT150 questions - Tre' 15:19:49 04/23/20 (0)

RE: Help with KT150 questions - Alex Kitic 14:09:52 04/21/20 (7)

RE: Help with KT150 questions - daveyf 13:31:18 04/22/20 (5)

RE: Help with KT150 questions - Alex Kitic 11:07:33 04/23/20 (4)

good post - Tre' 15:21:47 04/23/20 (3)

RE: good post - daveyf 15:38:12 04/23/20 (2)

RE: good post - Tre' 16:22:01 04/23/20 (1)

RE: good post - Alex Kitic 23:44:54 04/23/20 (0)

RE: Help with KT150 questions - Tre' 16:50:51 04/21/20 (0)

RE: Help with KT150 questions - ABliss 07:40:02 04/14/20 (2)

RE: Help with KT150 questions - daveyf 17:31:35 04/14/20 (1)

RE: Help with KT150 questions - ABliss 08:05:50 04/15/20 (0)

RE: Help with KT150 questions - LtMandella 23:41:06 04/13/20 (0)

Help with KT150 questions

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