How long do '65 DRRI Filter caps last (these are ICs)

bluesholyman

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NOTE: I made sure there were no unsafe voltages in the amp before I went poking around.

Backstory: I recently (a month or so ago now) acquired a 2014 '65 DRRI and it developed a hum on the reverb circuit and I felt I needed to take it in. After talking to the local amp tech (Fender authorized, etc.) he gave me a few things to try before I hauled it in. None of what he suggested involved cracking open the amp, but....I was curious about the (Illinois Capacitor) filter caps as I have heard they are notorious for failing anywhere from 2-10 years after manufacture. I had also been watching a few videos from Psionic Audio in Memphis and he seemed to have a less than favorable view of the caps and a few other things on the amp.

I opened it up, checked the caps which I saw no signs of leakage, checked for discoloration on the heater wires at the board and a few other things I had seen/heard. All looked good. Turned out the hum seemed to be either the driver tube or proximity to a power source (variac) - I replaced the suspect tube and moved the amp away from the variac - no more hum.

I noticed that the bright cap appears to have been changed out, presumably for a less bright value, but I didn't remove the control board to look - just saw the solder work.

Just wondering what experience from those working on these things says about the filter caps. My local tech seems to think the ICs last as long as anything else and the '65 DRRI is pretty bulletproof, while Psionic takes issue with some cost shortcuts Fender does on their amps. I am sure it can vary dependent on use/abuse but there should be some sort of bell curve around the number of years where most failures occur.

I guess I should check them every so often, but just wondering what kind of life I could expect and if at, say 10 years, I should just redo them and be done with it for another 10-20 years with a good cap set. I'd rather do them before they fail.
 
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Timbresmith1

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NOTE: I made sure there were no unsafe voltages in the amp before I went poking around.

Backstory: I recently (a month or so ago now) acquired a 2014 '65 DRRI and it developed a hum on the reverb circuit and I felt I needed to take it in. After talking to the local amp tech (Fender authorized, etc.) he gave me a few things to try before I hauled it in. None of what he suggested involved cracking open the amp, but....I was curious about the (Illinois Capacitor) filter caps as I have heard they are notorious for failing anywhere from 2-10 years after manufacture. I had also been watching a few videos from Psionic Audio in Memphis and he seemed to have a less than favorable view of the caps and a few other things on the amp.

I opened it up, checked the caps which I saw no signs of leakage, checked for discoloration on the heater wires at the board and a few other things I had seen/heard. All looked good. Turned out the hum seemed to be either the driver tube or proximity to a power source (variac) - I replaced the suspect tube and moved the amp away from the variac - no more hum.

I noticed that the bright cap appears to have been changed out, presumably for a less bright value, but I didn't remove the control board to look - just saw the solder work.

Just wondering what experience from those working on these things says about those caps. My local tech seems to think the ICs last as long as anything else and the '65 DRRI is pretty bulletproof, while Psionic takes issue with some cost shortcuts Fender does on their amps.

I guess I should check them every so often, but just wondering what kind of life I could expect and if at, say 10 years, I should just redo them and be done with it for another 10-20 years with a good cap set.
Don’t worry about it. If the amp starts humming or starts generating weird harmonics on low notes, then it’s likely time.
 

Phrygian77

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With modern caps like those ICs, an ESR test is good at weeding out the bad ones. If you really want to check them yourself, you can get a cheap ESR meter that will do the job. On vintage Fenders, an ESR test isn't sufficient because those older electrolytics are usually water based electrolyte, and they fail differently than modern ones do.
 
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sds1

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Word on the street is IC manufactured some problematic e-caps for Fender that seem to be isolated to the Blues Deluxe/Deville series amps. The resissues seem not to be affected and IC's are in general a quality part.

So, I'd tend to agree with your local tech.
 

Telenut62

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Word on the street is IC manufactured some problematic e-caps for Fender that seem to be isolated to the Blues Deluxe/Deville series amps. The resissues seem not to be affected and IC's are in general a quality part.

So, I'd tend to agree with your local tech.
 

bluesholyman

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This is the video that made me wonder about the filter caps in my amp. They looked good from what I could tell, but I might get them done in a few years just the same.

Edit: Something I just noticed - the caps in that video have black end caps where the radial leads come out. Mine are actually aluminum/sliver in color and are built just a bit differently.

So I wonder if it was only the ICs with the black ends that had trouble....
 




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