Coupling cap upgrade for Cary CAD-805C help

Sorry to have confused you. My Cary monoblocks are not 805's, and have four 6550s each(push/pull amps), hence: two coupling caps each. The Deulands are available(discounted) at Parts Connexion. The only caps that are currently regarded more highly, by those that have done extensive(and megabuck) listening tests, are the Deuland Cast-PIO-Ag. Your amps should have 4) 1500uF/450V filter caps, each. I usually buy my bigger electolytics from Digikey or Mouser. They are both very finicky about the manufacture dates of the caps they sell. (http://jimmyauw.com/2009/08/18/extreme-capacitors-battle-2nd-session/) (http://www.partsconnexion.com/PDF/duelund.pdf) (http://www.digikey.com/product-detail/en/MAL210447152E3/4565PHBK-ND/2552542?cur=USD)

You must have hit ENTER, about the time I did! BTW: as wonderful as the 805C is; it would be a shame to use anything less that a REALLY superb coupling cap. According to the schematic; both SET tubes are using a .22uF/450V coupling cap. the final output tube(845) has a 2uF cap, in parallel with the .22 oil filled. You needn't worry about the, "eye" tube(obviously). If you upgrade those .22's; you should realize a substantial improvement(ie: soundstage/more organic sound/cleaner & more extended high freqs, sans stridency).

Really appreciate your comment Rodman
So the 2uF cap is not benefit from upgrade?

I can go with Duelund (price wise) if I can find feedback about it on coupling function. I had my Merlins upgrade to Master status with Duelund caps

From schematic, I have no clue which power caps to upgrade.
Anyway, my goal is coupling caps, as Cary offer
Thanks

Hello Mt T: Cap upgrades will increase performance, almost anywhere in an amp. Certainly; in the case of that 2uF, but- the .22uF will be more noticable. The filter caps are the large ones that extend above the chassis, next to the power and output transformers(C2-5, in the parts list). Depending on how old the amps are; the replacement of those caps can yield dramatic benefits(especially dynamics/bass impact). The 805C came out in 1991, so- your pair could be as old as 22 years. A virtually guaranteed, drastic change in sound quality, with those 1500uF/450V Vishays installed(and they're some of the easiest things to swap out, in an amp). I would do the coupling caps first(especially while they are on sale), let them burn in(a couple hundred hours), so you appreciate the differences that they've made. Then, upgrade the power supply filter caps and brace yourself for the next level.

I have rolled all kinds of high end caps in the coupling position. The Mundorf SGO caps are good, but nowhere near the glorious sound and dead quiet background of the Duelund CAST caps.

The two best I have heard in tube amps and preamps are..

Duelund CAST caps
JB JFX Premium film caps

The JB caps come very close and only cost $3-$10 depending on size. They can be purchased at Just Radios in Canada.

They are not quite as extended in the top end as the CAST, but give little else up. The CAST have a blacker background also. the JB's have better bass and are a little warmer sounding without giving up any detail. I know it is hard to believe a $3 cap can sound that good, but they do. I prefer these over the Mundorf SGO's as well as several other Aphile friends that have tried them and now use them.