Every now and then a recovering tube-roller goes on a runner. I tried a stash of JJ KT-88s in my Sachs-modded ST-120 and gave them a pre-emptive run in, in excess of 20 hours. The cannon-fire on 1812 Overture sounds like an owl puking down from a high tree-branch onto a steaming hot cow-patty. I can't listen to 'em. My own rules say give any new tube at least 100 hours but I cannot listen to the JJs that long, sounding the way they do. Is Patience the guiding god here, or should I just leave them on the curb?
+2
peterh
deepee99
6 posters
How long a break-in time for JJ output tubes?
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
peterh
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
Restore the amp to original configuration. If that doesn't help , change speakers.deepee99 wrote:Every now and then a recovering tube-roller goes on a runner. I tried a stash of JJ KT-88s in my Sachs-modded ST-120 and gave them a pre-emptive run in, in excess of 20 hours. The cannon-fire on 1812 Overture sounds like an owl puking down from a high tree-branch onto a steaming hot cow-patty. I can't listen to 'em. My own rules say give any new tube at least 100 hours but I cannot listen to the JJs that long, sounding the way they do. Is Patience the guiding god here, or should I just leave them on the curb?
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
Then why do McShane's GL KT-88s and the Chinese KT-88 tubes work perfectly in these holes? I'm not going to re-configure everything just around a faulty quad of output tubes. I'd send the JJs back to the vendor but it's cheaper just to toss them in the trash. Work with me here. If they're such a great tube as you say the JJs are, how long need I wait to get a decent sound out of them?peterh wrote:Restore the amp to original configuration. If that doesn't help , change speakers.deepee99 wrote:Every now and then a recovering tube-roller goes on a runner. I tried a stash of JJ KT-88s in my Sachs-modded ST-120 and gave them a pre-emptive run in, in excess of 20 hours. The cannon-fire on 1812 Overture sounds like an owl puking down from a high tree-branch onto a steaming hot cow-patty. I can't listen to 'em. My own rules say give any new tube at least 100 hours but I cannot listen to the JJs that long, sounding the way they do. Is Patience the guiding god here, or should I just leave them on the curb?
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
deepee99 wrote:Then why do McShane's GL KT-88s and the Chinese KT-88 tubes work perfectly in these holes? I'm not going to re-configure everything just around a faulty quad of output tubes. I'd send the JJs back to the vendor but it's cheaper just to toss them in the trash. Work with me here. If they're such a great tube as you say the JJs are, how long need I wait to get a decent sound out of them?peterh wrote:Restore the amp to original configuration. If that doesn't help , change speakers.deepee99 wrote:Every now and then a recovering tube-roller goes on a runner. I tried a stash of JJ KT-88s in my Sachs-modded ST-120 and gave them a pre-emptive run in, in excess of 20 hours. The cannon-fire on 1812 Overture sounds like an owl puking down from a high tree-branch onto a steaming hot cow-patty. I can't listen to 'em. My own rules say give any new tube at least 100 hours but I cannot listen to the JJs that long, sounding the way they do. Is Patience the guiding god here, or should I just leave them on the curb?
30s, until fileament is warm and bias is correct.
if they don't work, they seems faulty. Let the vendor measure them again. I assume
you got them from eurotubes.
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
Yep, from Eurotubes. I don't mind a long blossom-time, just wondering how long. No offense given or intended. Just seems they take longer than most.
peterh- Posts : 1869
Join date : 2012-12-25
Location : gothenburg, sweden
It shouldn't be mer then a few minutes. Let eurotubes figure out ( if other kt88 sounds ok in your amp)deepee99 wrote:Yep, from Eurotubes. I don't mind a long blossom-time, just wondering how long. No offense given or intended. Just seems they take longer than most.
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Last edited by PeterCapo on Thu Dec 03, 2020 11:36 pm; edited 1 time in total
tubenutr- Posts : 78
Join date : 2015-01-25
Age : 67
Location : Northern Ontario
deepee99 wrote:Every now and then a recovering tube-roller goes on a runner. I tried a stash of JJ KT-88s in my Sachs-modded ST-120 and gave them a pre-emptive run in, in excess of 20 hours. The cannon-fire on 1812 Overture sounds like an owl puking down from a high tree-branch onto a steaming hot cow-patty. I can't listen to 'em. My own rules say give any new tube at least 100 hours but I cannot listen to the JJs that long, sounding the way they do. Is Patience the guiding god here, or should I just leave them on the curb?
deepee99,
Just tuck them away in the tickle trunk and on a rainy day, drag them out and hook up your tv to a Nascar race and let them run for ??? hrs.
I've have great luck with JJ's in both pre and power.
Its worth a shot. Or you can send them to me gratis......................
Mike
Dogstar- Posts : 361
Join date : 2014-06-23
Prior to the Genelex Gold Lion KT-88's and GZ34 I am currently running in my VTA ST-120 I was using TungSol KT-120's and a Webber SS rectifier and to be honest I thought the sound was much nicer than with the Genelex tubes which have at least 400 hours on them. There is nothing horrible about them ...but there is nothing phenomenol that I seem to remember from the KT-120's.
The 6SN7's I'm currently experimenting with in an adapter in the center position of the preamp section seems to help but I'm somehow feeling I'd be much happier with another quad of KT-120's. Sorry for the thread jack but I know the GL KT-88 get such high praise here...I'm thinking maybe I got just a so so quad as did the OP with the JJ's.
The 6SN7's I'm currently experimenting with in an adapter in the center position of the preamp section seems to help but I'm somehow feeling I'd be much happier with another quad of KT-120's. Sorry for the thread jack but I know the GL KT-88 get such high praise here...I'm thinking maybe I got just a so so quad as did the OP with the JJ's.
jfine- Posts : 152
Join date : 2017-06-19
Never liked any JJ tube I have heard, my brother uses em in his guitar amps, didn't like em either. I use them to fill holes in gear I'm selling 
arledgsc- Posts : 504
Join date : 2012-11-30
Same here.. never thrilled about JJ tubes but use them in guitar amps as they are dirt cheap in comparison to others.
Dogstar- Posts : 361
Join date : 2014-06-23
OK OK....given the dislike for JJ tubes in general I have the best answer to the question:
How long a break-in time for JJ output tubes?
And the answer is:
3 to 4 feet when dropped on a hard concrete surface.
Not to be snarky of course... :-)
How long a break-in time for JJ output tubes?
And the answer is:
3 to 4 feet when dropped on a hard concrete surface.
Not to be snarky of course... :-)
arledgsc- Posts : 504
Join date : 2012-11-30
Dogstar wrote:OK OK....given the dislike for JJ tubes in general I have the best answer to the question:
How long a break-in time for JJ output tubes?
And the answer is:
3 to 4 feet when dropped on a hard concrete surface.
Not to be snarky of course... :-)
