Kt90 Upper midrage forwarness

Hello,

Running Rogue Apollo amps with EH KT90's

Im getting an Upper mid range that's out of balance and Forward.

I have had other rogue amps with Kt88's without the Forwardness.

Considering going to EH kt-88's or Gold lion Kt88's

Have High efficiency speaker which is adding to this.

hiend208-14-2022 8:55pm

noromance Details Discussions Posts This discussion Message User 9,486 posts 08-15-2022 at 01:36am Copy Comment URL Report Comment Edit Delete Electro-Harmonix can be a little brittle at the top. Have you given them at least 20 hours? I've not heard the 90s but I have EH KT88s with that attribute. You may do better with the Tung Sol KT120. Also consider rolling the small signal tubes.
jjss49 Details Discussions Posts This discussion Message User 6,612 posts 08-15-2022 at 04:31am Copy Comment URL Report Comment Edit Delete agree eh power tubes can have a hard, glare-y sound, at least before substantial use/break in
decooney Details Discussions Posts This discussion Message User 1,906 posts 09-10-2022 at 11:16pm Copy Comment URL Report Comment Edit Delete @hiend2 you are not the first to report this about KT90s over the years. Agree with others here. EH new-production was a bit like that in my 6SN7 preamp and former KT88 amplifier too. Then, leapfrogged to KT120 and KT150s, and back to KT120s again for the past year in my now-current mono tube amps. IF you do decide to go with TS KT120s, no joke, give them 100hrs to settle down and settle in some. Was not a fan first 20hrs, and much more enjoyable after 100+hrs burn in. And, I will not attempt to explain why. Just is. Best of luck.