Hi,
Sorry to hijack this old thread. Please ask me to create a new one if that is more appropriate. I'm looking to replace the bulged power supply caps in a cambridge Azure 640R receiver. These are from 2007 and are custom "Cambridge Audio" 71V 15000u 105 deg.
I have seen several posts claiming that Cambridge power supply caps from this period are probably quite poor quality and should be replaced anyway. Question is by what? 15000u caps are not available in many of the preferred types for audio. Pnasonic FC's seem also to have been discontinued. What is the consensus for:
1. Sound should be at least as good as the original if not better.
2. Price and value are important
3. Can I go up in uF (22 000) without side effects?
I haven't measured the physical dimensions of the originals, but height is less limited than width.
Cheers!
Sorry to hijack this old thread. Please ask me to create a new one if that is more appropriate. I'm looking to replace the bulged power supply caps in a cambridge Azure 640R receiver. These are from 2007 and are custom "Cambridge Audio" 71V 15000u 105 deg.
I have seen several posts claiming that Cambridge power supply caps from this period are probably quite poor quality and should be replaced anyway. Question is by what? 15000u caps are not available in many of the preferred types for audio. Pnasonic FC's seem also to have been discontinued. What is the consensus for:
1. Sound should be at least as good as the original if not better.
2. Price and value are important
3. Can I go up in uF (22 000) without side effects?
I haven't measured the physical dimensions of the originals, but height is less limited than width.
Cheers!
similar questions but a different Thread !
http://www.diyaudio.com/forums/solid-state/279039-av-receiver-dilemma.html#post4433908
http://www.diyaudio.com/forums/solid-state/279039-av-receiver-dilemma.html#post4433908
Thanks Apogee lover.
I took a look at the website. Actually the main problem seems to be in finding anything with similar parameters to the original:
snap-in
15000uF (or more)
71V. max.
105 deg. temp rating.
I took a look at the website. Actually the main problem seems to be in finding anything with similar parameters to the original:
snap-in
15000uF (or more)
71V. max.
105 deg. temp rating.
An externally hosted image should be here but it was not working when we last tested it.
something like this LKG1K153MKZ Nichicon | Mouser if you can find stock, and dimentions are compatible would probably fit the bill.
edit: or a cheaper alternative http://www.mouser.com/ProductDetail...=sGAEpiMZZMtZ1n0r9vR22ZriOvlTFyShWMm/SYjoo9w=
Tony.
edit: or a cheaper alternative http://www.mouser.com/ProductDetail...=sGAEpiMZZMtZ1n0r9vR22ZriOvlTFyShWMm/SYjoo9w=
Tony.
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Yes,
I was wondering about Nichicon KG,
Nichicon KG Type | Hifi Collective
But these, and the LKG's you mention are only rated up to 85 deg. C. The caps are close to the main, output stage heatsink and may be subject to high temperatures. This could be why the originals, rated at 105 deg. are already blown after 8 years??
I was wondering about Nichicon KG,
Nichicon KG Type | Hifi Collective
But these, and the LKG's you mention are only rated up to 85 deg. C. The caps are close to the main, output stage heatsink and may be subject to high temperatures. This could be why the originals, rated at 105 deg. are already blown after 8 years??
OK yes that could be an issue. The life of a cap at their max rated temperature is not that long (typically between 2000 and 5000 hours). At temperatures less than their max rated they last a lot longer. I would hope that they wouldn't be seeing temps greater than about 60deg C but if ventilation is not great maybe it gets hotter. But a 105 deg cap should last a lot longer than an 85 deg cap at 60deg.
I guess it comes down to what sort of temp they are actually seeing, and why the originals failed (as 8 years is pretty short life for PS caps). 71V is an odd voltage rating, what voltage are the rails on the amp? Maybe the problem is that the caps were not very conservatively rated and were actually working close to their limit...
Tony.
I guess it comes down to what sort of temp they are actually seeing, and why the originals failed (as 8 years is pretty short life for PS caps). 71V is an odd voltage rating, what voltage are the rails on the amp? Maybe the problem is that the caps were not very conservatively rated and were actually working close to their limit...
Tony.
Hmm... Rail voltage is +- 55V. so not that conservative.
As the unity is secondhand, I'm not sure about ventilation. The top was quite discoloured, which might suggest that it was running warm for some time?
Having said all that, the unit sounds pretty good to me, so the only indication I have that the caps are shot is the bulging of the tops, but I'd rather change them now than wait for them to die completely, maybe bringing down other components as they go.
As the unity is secondhand, I'm not sure about ventilation. The top was quite discoloured, which might suggest that it was running warm for some time?
Having said all that, the unit sounds pretty good to me, so the only indication I have that the caps are shot is the bulging of the tops, but I'd rather change them now than wait for them to die completely, maybe bringing down other components as they go.
I had one fairly cheap 15mF 63V Nichicon that after some amplifier testing as one of a group of six that appeared to have a bulge. Since I had many spares I swapped it out.
Ran a leakage test and a capacitance check and it appeared to be OK. I still have it on the shelf some years later.
Maybe another couple of checks are worth while.
Maybe a long term charge at 60 to 63Vdc would prove something?
I don't know if I was overly cautious.
Ran a leakage test and a capacitance check and it appeared to be OK. I still have it on the shelf some years later.
Maybe another couple of checks are worth while.
Maybe a long term charge at 60 to 63Vdc would prove something?
I don't know if I was overly cautious.
Hi Andrew,
You may well be right that swapping them out, purely on the basis of the bulge may be unnecessary. My reasoning was that the electrolytics should probably go after another couple of years anyway and that it would be an excuse to do the job a little earlier. While I'm, at it, I'll probably swap out all the signal path caps with silmic's and may raise the capacitance of the psu caps.
Anyway, the amp sounds okay, so I may well leave it for at least another few months, but good to know what to go for when I finally do tackle it.
You may well be right that swapping them out, purely on the basis of the bulge may be unnecessary. My reasoning was that the electrolytics should probably go after another couple of years anyway and that it would be an excuse to do the job a little earlier. While I'm, at it, I'll probably swap out all the signal path caps with silmic's and may raise the capacitance of the psu caps.
Anyway, the amp sounds okay, so I may well leave it for at least another few months, but good to know what to go for when I finally do tackle it.
The 1 volt difference could have nothing to do with the filter caps.
For example, the power transformer windings may be matched well enough for their purpose, but they are not perfect. Wisdom may suggest moving on... ;-)
I read a blurb in another, ahem, forum recently in which it was stated that by far the biggest improvement in the overall sound is achieved by upgrading the filter caps to really good ones. He said that putting better caps in the pre or power amp section had far less effect(?) Doesn't make sense to me. I would think that what's in the signal path is most critical, good film caps and 1% metal foil resistors. Aside from the "sag" produced by undersized caps under heavy load, It's job is to supply steady, clean DC, period. Is a slight bump in ripple current, ESR, or whatever you call it, noticeable? What sayest the panel??
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