High-quality capacitors needed for valve amp PSU

[Rare Bird]

Cerafines wernt like standard Electrolytics they used ceramic particles, i doubt they will break down with age..I pesonally would buy the Mundorf nowadays..

[Marco]

Ah, I see what you're saying about the Elnas...

Dunno why BHC don't seem to do the right values, though. Farnell has 100s of them (some rated at 500V), but none of the right capacitance

Perhaps if I emailed them, they'd make some up as a special order? ICW (Clarity cap) may also do that....

Marco.

[lurcher]

I would avoid NOS electrolytics (unless I am selling my small stash of BG WKZ's :-)). Does the value have to be that exact Marco? I think your amp is SS rectifier, so larger valves should do no harm, and could be a benefit. 500v electrolytics are far less common, 450v is the normal voltage limit, but 500v do exist. Though I use lower voltage ones in series for higher voltage use. You could also look at Motor run film caps.

[anthonyTD]

hi Nick,
marco's amp uses a pair of GZ34 rectifiers so the first resevoir cap is limited to 50uf, the caps i used were original plessey 16 +16 and i doubled up the first in line to give 32uf, the voltage rating of 500v is to make sure they are absolutely safe with the surge voltage from standby mode.
obviously the caps used elsewhere in the circuit could be 450v working.
Anthony,TD...

[lurcher]

Ahh, sorry, I stand corrected. So, yes, you have the limit on the first cap after the rectifier,

[Marco]

Cheers, chaps. Anthony, you have email!

After some digging, and much help from Andre (and Nick), the front runners are now custom options from Ansar, such as mentioned here:

http://www.suppression-devices.com/a...apacitors.html

I like the idea of being able to specify solid silver lead-out wires, etc... And judging by the description, they seem like superb quality:

http://www.suppression-devices.com/a...al.html#Choice

Also, there is the option of going for custom ones from ICW in Wrexham. They of course make the superb Clarity Caps. Their PCS range, looks ideal for Copper amp duties:

http://www.icwltd.co.uk/power4/image.htm

Now, I use the MRs in the crossovers for my Tannoys, which are superb, so if the PCS range is as good, then it would be a VERY valid option indeed...

Decisions, decisions!

I'll have a chat with Anthony about this, but what do you think would be the best move, Nick? Bear in mind that I would like the absolute best caps possible (sonically speaking), as this job will be a case of 'do it once and do it right with no compromise', if you see what I mean.

Marco.

[lurcher]

Any of those would be good. I would chose what fits the case best.

[Marco]

Good point, and very relevant! However, presuming that both types will fit, if it were you doing the job, which ones would you be inclined to go for?

Perhaps based on the spec/descriptions of the caps mentioned on the respective websites and/or the reputation for quality of both companies.... (or anything else you consider important).

At the moment I'm leaning towards ICW, simply because of their level of expertise in the professional industry and amount of resources available for R&D....

Marco.

[StanleyB]

Capacitors are made out of a range of materials for a reason. Manufacturer reputation counts for nothing if the end user uses the wrong type of capacitor material for a critical job.

Also keep in mind the tolerances of the cap. A 32uF would have to have a tolerance of less than 5% before it is guaranteed to be any different to a 33uF cap.

[leo]

I've heard various flavours of WAD 300b amps, one was full of polypropylene caps in the psu, it sounded very different to the others containing lytics, brighter with lighter bass, the brightness was a little much for me with busy music in the system I heard it in . Of course it all comes down to system and taste. They may also work great in the copper amp , just thought its worth mentioning though

I've known high capacitance lower voltage NOS caps to work ok after being properly formed, not sure about the higher voltage types though, probably best to avoid if unsure.

Never tried these http://www.jj-electronic.com/pdf/TC_TE.pdf