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Blowing tubes


Coytee

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Is this the world I've walked into?

bought a new Jolida and within 3 weeks one of the tubes blew on me. No problem, Jolida replaced the tube. On installing the new tube, I noticed & remembered that I could NOT bias one of them up to 50 even with the knob turned full bias. Jolida said tube was bad & said they'd send another.

they DID send another tube, but got mixed signals and ALSO sent an entire new AMP.

I swapped out the amp, kept the new tubes.

In the meantime, I'd ordered a full compliment from tube supply (I forget name) anyways, and bought KT90's.

So far on the "old" amp, I had 1 tube cherry out and another (according to Jolida) as a matter of time.

Now I have an entirely NEW amp by happenstance, install the KT90's and what happens last night but one of the tubes flares up, blows the fuse.

I replaced the fuse and it "seems" to work just fine but I'm a bit nervous about the tube that flared up.

In total fairness, the tube DID flare up during some loud music, but my gut feeling says it wasn't clipping (to be brutally honest here, I don't know if I even know what clipping sounds like, so if it's OBVIOUS as to it's sound, then I've NEVER heard it)

Anyway, I COULD have concluded that maybe I had a buggy amp to have 3 tubes die on me, but again, 2 were on old amp, and this is on new amp.

Are tubes just this finickey?

Is it just my wonderful luck?

Would I be better off getting a BIGGER amp for cranking? (idea is, it stresses the tubes less perhaps)

I'm perplexed

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My guess is that this particular amp may not be that reliable, especially for cranking. But, its not that way for most tube amps. Before I journeyed into tubes about a year ago, I recalled some posts from Jolida owners who were having some difficulties with their amps. Sorry, but I do not remember the specific nature of the problems or the models involved. Before you continue to get frustrated with this tubes thing, do some in-depth research on the web and various forums about this amp - see if others have had some similar problems. My Jolida tubed CD player has been very reliable, but I cannot speak to their tube amps.

Generally, blowing tubes is not a problem with amps. Most tubes last a long time. My personal experience is with three tube amps, two Dynacos and one Marantz. Lots of loud music, but no tube problems to date. Good luck and keep us posted.

Carl.

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by checking the line voltage, I presume you mean at the plug?

Hadn't thought of that. Though because of where I live (out in country on dead end road in middle of NOWHERE) I'm sure we sort of get the "what's left over" after everyone else gets the good stuff lol. Point being, it's probably erratic than static.

We're first to lose power, last for it to be reinstated, only 5 houses out here on a peninsula of perhaps 1,000 acers (just a guess)

Anyways, I'll check the wall plug.

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What peninsula are you on in TN? Sheesh, probably that TVA power all along. 2.gif

We lived in the country in Wisconsin, and every moring the lights would start getting bright at about 6:25. At 6:30 the lights started getting dimmer. I figured the utility (electric co-op), woas cranking up the power for all the milking machines at the local dairies. Light bulbs didn't last too long there.

Marvel

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On 1/29/2005 7:59:13 AM Coytee wrote:

Is this the world I've walked into?

bought a new Jolida and within 3 weeks one of the tubes blew on me. No problem, Jolida replaced the tube. On installing the new tube, I noticed & remembered that I could NOT bias one of them up to 50 even with the knob turned full bias. Jolida said tube was bad & said they'd send another.

they DID send another tube, but got mixed signals and ALSO sent an entire new AMP.

I swapped out the amp, kept the new tubes.

In the meantime, I'd ordered a full compliment from tube supply (I forget name) anyways, and bought KT90's.

So far on the "old" amp, I had 1 tube cherry out and another (according to Jolida) as a matter of time.

Now I have an entirely NEW amp by happenstance, install the KT90's and what happens last night but one of the tubes flares up, blows the fuse.

I replaced the fuse and it "seems" to work just fine but I'm a bit nervous about the tube that flared up.

In total fairness, the tube DID flare up during some loud music, but my gut feeling says it wasn't clipping (to be brutally honest here, I don't know if I even know what clipping sounds like, so if it's OBVIOUS as to it's sound, then I've NEVER heard it)

Anyway, I COULD have concluded that maybe I had a buggy amp to have 3 tubes die on me, but again, 2 were on old amp, and this is on new amp.

Are tubes just this finickey?

Is it just my wonderful luck?

Would I be better off getting a BIGGER amp for cranking? (idea is, it stresses the tubes less perhaps)

I'm perplexed

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Hello,

Sorry to hear about your problem. I may have a similar story to share. The tubes which are giving you the problems aren't by chance JJ KT88s? If so, I may have some insight.

I KNOW how you feel,

Analogman

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On 1/29/2005 1:40:39 PM Parrot wrote:

Come on Analogman, spill the beans on these tubes. Are they badly made?

Anyway, such a scenario would be discouraging to anyone. But a good amp with good tubes should rarely have problems.

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Not really, just a little mold 'n' dirt! 3.gif

Where're we goin'?

Analogman

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The only problem that I have encountered with my Jolida 302B is with the tube sockets. Twice, like you they lost contact on the grid and ran away. I caught it the first time the second fried the tube.14.gif

My fix was to install some octal sockets from a '60s vintage Sansui amp and have had no problem since. The Chinese make a lot of things well but have yet to master the art of tight connections to tube pins.

Coytee, you should not have to put up with this stuff. It is NOT normal for tube amps to blow tubes. Go to your dealer and insist that he replace the defective sockets preferably with old ones.

Rick

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Coytee, you should not have to put up with this stuff. It is NOT normal for tube amps to blow tubes. Go to your dealer and insist that he replace the defective sockets preferably with old ones.

Rick

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Had this happened to the same unit, I'd tend to think something is defective. Since I swapped out units already, my gut says those odds aren't quite as high (though it's certainly still possible)

The "new" tube that nuked on me was an Electro Harmonix (sp?) KT90 as opposed to an 88 or the JJ.

As far as where in TN, I'm just outside of Knoxville. I live in Greenback which is a place that you can't get to unless you first travel through Maryville or Lenoir city 3.gif

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On 1/29/2005 12:31:32 PM Coytee wrote:

Only 5 houses out here on a peninsula of perhaps 1,000 acers (just a guess)

Anyways, I'll check the wall plug.
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That could be the worse case. On long runs, some power companies will jack up the voltage to compensate for line loss.

It wont cost much to measure it.

DR BILL

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On 1/30/2005 4:41:55 PM Marvel wrote:

That is a beautiful part of Tennessee (a lot of it is nice
2.gif
). I was curious, as I live just south of Chattanooga into Georgia, having gotten out of the city in '93.

Marvel

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Howdy semi-neighbor 9.gif

If you ever got up this way and heard of Tellico Village (retirement community on Tellico Lake), well... that's not where I live 11.gif

I happen to live opposite of the village on Tellico Lake. Ya, Pops in law owned like 1,500 acres out here, TVA came along & when they decided they needed everyone's land, took all but about 250.

That's the "bad" part. the GOOD part is, "we" are the peninusla. There are two large coves and they border 'the farm' where I live. Other than TVA who owns the literal lake front ground, pops in law owns the entire peninsula.

Though I came out here kicking & screaming (city boy moves to east of BF egypt kind of thing) I must admit I now love it. The fact that development has now started on OUR side of the lake and is but 2 land owners away from knocking on our door is interesting too.

12.gif

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