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Need some advice. Had the bottom plate off my Art Jota HC amp yesterday, and noticed that one of the electrolytics has a bulge in the top of it. Not leaking, but that bulge concerns me as it's rather pronounced. This amp is nearing 18 years of age, so it's probably time to look at replacing all the electrolytics anyway. The one in question is a Cornell Dubilier 100uF 400v with radial solder leads (12 of 'em in total), presumably an aluminum 'lytic. Can't seem to find identical replacements online, other than Mouser that has a minimum 2k order quantity and 17 week lead time for that particular cap. Any suggestions for a good replacement? There's reasonable room to the sides and top of each cap so that matching the Dubilier's dimensions exactly isn't critical. I don't care so much about cost (within reason), but I am concerned about changing the sound of the amp. I love it the way it is, and don't want to change anything. Unfortunately, Art Audio is no longer around, so getting their input isn't an option. Any suggestions?
Panasonic and Nichicon offer some superb 'lytics. If possible, select parts rated for 105 o C., for increased longevity/reliability.
If the mechanical fit is satisfactory, the Panasonic part linked below should prove highly satisfactory in your amp.
I have had people ask me about bulging capacitors, and I found that it was just the plastic disk on the bottom that had warped. Now, you may very well have a genuine problem, but it would be nice if you had the ability to run some technical measurements. Bulging capacitors usually do not test as normal.
That could well be all that's wrong with mine. I pushed on the area that was popped up, and it's pretty hard under there (no flex), but that could just be deformed plastic. I have a simple capacitance meter, but not sure how well it will work with the caps in circuit, plus I'd have to get the board out of there (which will take some work) to get to the contact points. Don't have any other testing tools beyond a DVM, unfortunately. Should have taken a picture of it when I had the bottom off...
Thanks for the info!
Any bulging electrolytic, you need to replace it.
Do not power up the unit with that cap visible to you, and wear eye protection when examining the amp. A failing electrolytic can explode violently at any time, spewing electrolite everywhere. You don't want to have to clean that up and you don't want bits of capacitor hitting you in the eye.
there is usually a good selection of caps in that range. If no CD, Nichicon and Panasonic are very good as well.
I haven't looked extensively yet. I see 100uF/400v caps on CD's website in a couple different varieties, but haven't easily found a retailer for them at this point. I'm wondering if Joe Fratus selected this lesser-known cap for a particular reason, or whether they were just easily available to him and priced how he wanted. Don't have a schematic, or I'd be asking for some advice on what would be best to use. :)
Good to know the Panasonics and Nichicons are good to use...I haven't bought any electrolytics since some Black Gates 20 years ago.
I can't speak to what the designer was thinking but I tend to use caps that i like sonically and that are readily available. But, you can use caps of higher voltage as a sub with no down side. Also, electrolytic caps have advanced in design since the time when your amp was built and especially when the caps in your amp were manufactured.
at the link. I have been replacing the electrolytics in 2 of my SET amps with these to a very good benefit.
The 100uF/500v caps have snap-in leads....I'll have to get the board pulled out to see of the PCB holes are large enough. Pricey too, but then I did just say that cost was not the main factor. :) Thanks for the suggestion and the link. !
In my estimation and others, they sound better then Black Gates and break-in is not an issue.
I live in Europe, but there are a number of AN(UK) dealers in the US. Check the AN(UK) home page.
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