jtrollmann
Joined: Jun 24, 2021
Posts: 129
South Bay, CA
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Posted on Jul 09 2024 11:28 PM
I own a three year old Fender Deluxe Reissue. Upon turning it on tonight, I heard a loud pop. That never happened before. Looking at the two 6V6 power tubes, I noticed that one is burning 3-4 times brighter than the other 6V6 (in the photo it's the left tube).
I shut it down and switched the two tubes. Upon start up, another loud pop. This time the same tube now in the right socket is still lit super bright. These are the original power tubes. I play nearly four or five times a week. Otherwise the amp sounds strong.
Any ideas? Is it time for new 6V6s? This does not look normal.
— -John
"...enjoy every sandwich." -Warren Zevon
Fender Stratocaster American Pro II
Fender '65 Deluxe Reverb Reissue
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DaveMudgett
Joined: Mar 17, 2019
Posts: 162
Central PA
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Posted on Jul 10 2024 03:36 AM
I wouldn't start it up again with these tubes. A loud pop is not normal. That fact that it moves with the tube suggests there's an issue with the tube. But I'd still want to make sure there isn't a problem with the power tube circuit sections. Even if there wasn't before, a bad tube can take out components.
It's a bit hard to tell, but is the plate actually red, or is it just the filament that's glowing brighter? If the plate is red, that would indicate that there's too much current flowing from the cathode to anode *plate). But too much filament current is a problem too. You don't want to stress the filmament windings in the power transformer.
A vintage Deluxe Reverb runs pretty high plate voltages on the power tubes. Nominal is around 420-430 VDC. I don't think that changed with the reissue. Design center for a 6V6 is around 350-360 VDC. Tubes used to be designed with a fair amount of margin, but I don't have the same confidence in most modern tubes.
If you have a pair of known good 6V6 tubes, you could try them. If anything pops with them, turn it off immediately and get it to a qualified tech. Or you could just get it to a tech, period.
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synchro
Joined: Feb 02, 2008
Posts: 4446
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Jul 10 2024 07:43 AM
The OEM tubes from Fender are hit or miss. I’ve seen some that were great, but not all of them. If the problem follows the tube, then it’s probably just a tube going bad. A minute on a tube tester would probably tell the tale. Unless you are equipped to set bias and have the experience, I’d suggest finding an experienced tech.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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jtrollmann
Joined: Jun 24, 2021
Posts: 129
South Bay, CA
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Posted on Jul 10 2024 10:12 AM
From what I can see, it's not the plate that is glowing, but the element inside of the plate that is glowing hot.
I will order a pair of new 6V6s. But it is my understanding with the installation of new power tubes, the amp would need to be re-biased. And since I'm not comfy trying the bias thing, I'll search for an amp tech.
Any recommendations on a brand of new production 6V6s?
— -John
"...enjoy every sandwich." -Warren Zevon
Fender Stratocaster American Pro II
Fender '65 Deluxe Reverb Reissue
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synchro
Joined: Feb 02, 2008
Posts: 4446
Not One-Sawn, but Two-Sawn . . . AZ.
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Posted on Jul 10 2024 10:25 AM
jtrollmann wrote:
From what I can see, it's not the plate that is glowing, but the element inside of the plate that is glowing hot.
I will order a pair of new 6V6s. But it is my understanding with the installation of new power tubes, the amp would need to be re-biased. And since I'm not comfy trying the bias thing, I'll search for an amp tech.
Any recommendations on a brand of new production 6V6s?
I’d talk to the tech. The last time I bought a pair of 6V6s, they were JJs, and they sound great to my ear. YMMV.
— The artist formerly known as: Synchro
When Surf Guitar is outlawed only outlaws will play Surf Guitar.
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jtrollmann
Joined: Jun 24, 2021
Posts: 129
South Bay, CA
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Posted on Jul 10 2024 10:44 AM
Thank you! I'll be contacting amp techs this week. I'm in So Cal (Long Beach - Torrance area), so if anyone can recommend a tech, I'd appreciate it.
— -John
"...enjoy every sandwich." -Warren Zevon
Fender Stratocaster American Pro II
Fender '65 Deluxe Reverb Reissue
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jtrollmann
Joined: Jun 24, 2021
Posts: 129
South Bay, CA
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Posted on Jul 29 2024 03:20 PM
Update:
I got the Deluxe Reverb back from the tech.
One of the power tubes was shorting out due to a piece of the cathode flaking off and causing it to glow brightly. So I got a matching pair of new power tubes and a re-bias. The rectifier tube was also replaced.
The tech also replaced the two 1/2 watt screen resistors on the circuit board with 2 watt metal oxide resistors that he relocated to the tube sockets.
— -John
"...enjoy every sandwich." -Warren Zevon
Fender Stratocaster American Pro II
Fender '65 Deluxe Reverb Reissue
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edwardsand
Joined: Jun 29, 2018
Posts: 756
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Posted on Jul 30 2024 08:39 AM
So why was the rectifier tube replaced? Those usually have a long life. Was the original one defective or did it get damaged?
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jtrollmann
Joined: Jun 24, 2021
Posts: 129
South Bay, CA
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Posted on Jul 30 2024 10:40 AM
edwardsand wrote:
So why was the rectifier tube replaced? Those usually have a long life.
That's what the tech said when I delivered the amp for repair. When I asked about the rectifier he said it's probably still good because they last a long time. But upon inspection, he said the rectifier was microphonic. He also noticed some flaking at the bottom of the tube, so he replaced it.
I tried the amp out last night and it sounds great. Quiet upon power up and shut down.
— -John
"...enjoy every sandwich." -Warren Zevon
Fender Stratocaster American Pro II
Fender '65 Deluxe Reverb Reissue
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chiba
Joined: Sep 02, 2022
Posts: 514
Central VA
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Posted on Jul 30 2024 02:04 PM
edwardsand wrote:
So why was the rectifier tube replaced? Those usually have a long life. Was the original one defective or did it get damaged?
Chiming in ... given the damage to the power tubes, I would have re-tubed the entire amp as a matter of course. If it was my amp, I'd be worried about every tube I didn't replace to the point of distraction!
(Yes, I saw the OP's reply about the apparently dodgy rectifier ... just adding my two bits.)
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