Cambridge Audio Azur 550A Power Supply Cap Replacement

[3Phase615V]

Hi,

I isolated a power supply failure in my Cambridge Audio Azur 550A to a shorted filter cap (C42, page 37 - see service manual attached) on the +45V supply of the right-hand channel PCB. The faulty cap is a Cambridge Audio branded "Audio Grade" 2200uF, 63V, 105°C 18mmx35.5mm (see attached photo), for which CA have refused datasheet information and the supply of a replacement(s) as they advise they do not supply these items to "end users".

Since audio grade caps rarely appear available at more than 50V (105°C) it has me wondering whether or not a couple of decent quality non-audio grade Nichicon or Rubycon caps will suffice in the C41 and C42 positions (my intention is to replace both +45V side filter caps to reduce any untoward imbalances between original and non-original caps).

Given that audio grade 2200uF, 63V, 105°C capacitors appear to be a rare item, I am looking for suggestions for potential replacements (brand and series) that I can use in place of the original CA caps. I would think that low ESR, high ripple would the guiding parameters, but the latter can be quite a range. In other words, what is considered too low, high enough or even excessively high ripple current for a cap for this particular purpose?

So far I have been looking at the caps below, with the last two (Rubycon and Vishay) having quite substantially higher ripple current figures than the other three. Are these suitable/compatible? I am also wondering if leakage is a particularly important parameter to pay attention to for this usage:

Nichicon UVZ1J222MHD

Nichicon UVY1J222MHD

Panasonic ECA1JHG222

Vishay MAL214258222E3

Rubycon 63ZLJ2200M18X35.5

Thanks in advance for any advice and suggestions.

Tony

[stj]

scumbags.
you dont use "audio grade" caps on power rails.
look for low impedence caps with the highest ripple current you can find - preferably with a decent lifespan not some 1000hour shit

[redwire]

I would say the custom capacitors are for marketing wank and wooing reviewers, and for having a poor lifetime... strange it shorted.
Sonically, low ESR and high capacitance are audibly better. I think Cambridge Audio saved money by keeping them relatively small value.
Note the capacitors experience audio-frequency ripple currents (as well as mains) - so look at the 10kHz ESR spec as well for a figure of merit.
So I think an SMPS-grade capacitor is more what these are.

If it was my amplifier I would upsize the caps as 2x2,200uF per rail per channel is a bit lean, not the greatest. If you have the height see what might work.
pic from Azur 651a

edit: the problem is the small height.
Nichicon UFW1J222MHD "Audio grade" 2,200µF 63V 2,000Hrs @85°C but more of a placebo.
Taller, like 37.5 to 41mm MUCH BETTER:
Nichicon UHW1J222MHD 20mohm 3.86A @ 100kHz ripple. But 18x40mm high.
United Chemi-Con EKYB630ELL222MM40S 10,000 Hrs @ 105°C, very low ESR 16mohm 3.67A @ 100kHz ripple. Nice. But 18x40mm. I would stuff them in lol.

[3Phase615V]

Hi stj and redwire,

Thanks for your replies and advice.

It looks like didn't miss out much with the most sensitive parameters for my particular cap requirements. I was thinking I might be better focussing on longer life caps than the ones I found first off and you have confirmed that is worth doing- thanks.

I want to try to stick with the original cap sizes (18x33.5), so I will continue looking for similar caps to the ones you have suggested, but the parameter figures are useful to me in that search, so thank you again.

By the way, I meant to type I had the Azur 650A not the Azur 550A (hence requiring the larger voltage caps).

The cause of the fault, I suspect, was a power surge or outage that caused the ring main fuse to trip while the amp was on standby. I cannot be sure though as I did not immediately use the amp in the days after the trip event.

Thanks!

Tony

[RJARRRPCGP]

Originally Posted by stj

1000hour shit

Sounds like 1920s' incandescent light bulbs, LOL.

[petehall347]

just put long life ones in and call it an upgrade .

[stj]

how wide and tall can you actually fit?