janlf
Full Member
Moment's Notice
Posts: 173
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Post by janlf on Jan 13, 2009 1:56:18 GMT -7
Hi, Folks.
I have a almost brand new Rt66 that I brought with me on it's first here. The amp and the tubes maybe have about 10 hours of playing. It have happened one time at home as well, but both the loud hum and the hot smell went away when I turned it off, and than back on again. It seem like the amp is playing and sounding fine, but now both the hum and the smell won't go away. I'm thinking the KTs or the EF86. Anyone please?
JanLF
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Post by DRZ on Jan 13, 2009 6:07:47 GMT -7
I replied to your E-Mail with a question about the KT-66's. If they are Groove Tube Orange labels, those are big tubes with a lot of Orange paint. I think you have two slight problems.
One the amp maybe slightly over-biased ( do to to your wall voltage being slightly above 240V.) This will cause the tubes to heat up excessively and slightly burn the nice Orange paint hence the smell. And second if the tubes are just a touch out of balance they may hum a little.
What would I suggest :
Swap positions of the KT-66's in the chassis , make sure they are seated well. Turn the bias pot down a touch I would say a 1/4 turn CW for a non scientific approach, but better to get the bias checked and set the KT-66's to say 28 to 30 mA each. Also check your wall voltage I bet it's on the high side.
The paint smell will subside , some are just more sensitive then others, and turning down the bias will help the hum.
DR.Z
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Post by Phil (aka Phil) on Jan 13, 2009 17:30:00 GMT -7
One the amp maybe slightly over-biased ( do to to your wall voltage being slightly above 240V.) DR.Z High wall voltage? Isn't that normal at the Z-Factory? I though Broadway Ave. always runs up around 126V-128V ;D (sort of an inside joke; I work in Power Quality Engineering but at a different electric utility than Z is fed by)
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janlf
Full Member
Moment's Notice
Posts: 173
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Post by janlf on Jan 16, 2009 15:29:06 GMT -7
Hi again and thank you for your reply.
I forgot to tell you that the hum was coming out of the speaker cab.
Yes, the tubes are GT orange labeled as you suggested. I have not tried to do anything or played since my first post/email. But now I did measured the wall voltage to exactly 240V. I also did swap the tubes and took the chassis out and turned down the bias pot a notch. I then hooked it up to my Z 2X12" and turned it on. The tubes glowed up as usual, but it took the 3Amp fuse in a second when I turned the standby switch. Just a load "bang" and no smoke or smell. So are the KT's or at least one of them gone maybe? I have 2 brand new TAD KT sets that I can try to put in there. What you think?
Best regard, JanLF
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janlf
Full Member
Moment's Notice
Posts: 173
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Post by janlf on Jan 26, 2009 15:01:01 GMT -7
Hi again, I replaced the fuse, rectifier and both the KT's and adjusted the bias and she plays like a dream again . Thank you so much for your help. Greetings from Norway, JanLF
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Post by dongiesen on Jan 26, 2009 20:30:28 GMT -7
Thank goodness.
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Post by bluzman on Jan 28, 2009 18:39:55 GMT -7
Route66 hums and smells very hot Sorry to say this, but with the guys I play music, if they heard this the response would be: "So does your sistah!" ;D ;D ;D ;D ;D ;D Sorry, I crack me up!!
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Post by anotherlefty on Mar 3, 2009 13:54:32 GMT -7
im late on this one bluzman but i was waiting for that one!!
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