KT-88 bias help?

  • Thread starter Thread starter Capulin Overdrive
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Capulin Overdrive

Capulin Overdrive

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putting some =C= KT-88's in my Elmwood.


got the tubes from Tube Depot, the sticker on them says (bias point 47). which i guess is thier rating system, something to do with a guass curve?


according to the Weber bias caculator, i should be biased give or take a little from 41ma as my plate voltage bumps around between 595 to 600.


however with it biased at 41, it's not sounding all that great? crank the bias up to around 46ma and it's sounding pretty good, and plate voltage is still in the 595 to 600 range.


so guess my question is if the 46ma is too hot? i don't know how to figure what percent that is?


also the tube closest to the transformer is maybe 4 or 5 ma hotter, i'm gonna switch them and see if that helps? but the ma figures i'm giving are from the hottest tube.
 
You're still safe at 46 mA. That is just a hair below 70% plate dissipation. If it sounds good there, leave it. If your tubes are within 5 mA of one another, they're still matched.
 
cool! 46 it is then!


switched the tubes around, and it's the tubes that are deferent more so than being closer to the tranny.


also swapped the Chinese back in and gave them a shot biased up nice and hot. the SED's kick thier ass for me, SED's feel better to play and have a smoother bottom end. the Chinese have boomy bottom and are maybe brighter for leads?
 
i may have to try some of the Gold Lions.


the SED's are really good, but they're also pretty similar sounding to the SED EL-34's, so i've got that covered allready.
 
which chinese kt88's are you using? I like the shuguang ones but maybe not good for your amp. I like them in a high gain amp because they do have a giant bottom sound and to me a better midrange then the winged c. I think that was pretty accurate to say that the winged C kt88 sounds like there el34, it's pretty similar but with a bigger bottom of course.
 
Loudness250":396dqjtj said:
which chinese kt88's are you using? I like the shuguang ones but maybe not good for your amp. I like them in a high gain amp because they do have a giant bottom sound and to me a better midrange then the winged c. I think that was pretty accurate to say that the winged C kt88 sounds like there el34, it's pretty similar but with a bigger bottom of course.
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the Chinese are whatever Elmwood put in from the get go, they are defenantly good tubes.


the amp is sitting on top of old school greenbacks, and the SED's just got along better with those without the boomy bass of the Chinese. deferent speakers, and the Chinese might have come closer to being the winner.
 
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