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In the Forum: Analog Playback
In the Thread: The K&K SE hybrid phono stage: a report
Post Subject: Duelund caps: sanity check.Posted by Romy the Cat on: 3/9/2009

 drdna wrote:
Actually, I believe they can be tailor made to your exact specifications, which at that price they should be.

It is not a thread about cup but I still….

This is always an interesting question to me – where is the threshold between rational and irrational when I think about capacitors.  The expensive caps made to exact specifications sound like rational but there are no expensive caps that need to hit exact specification. The small caps on some cases need to be very exact but slam caps are not expensive. The large and expensive caps do not need to be exact, nether in uF number, nor in leakage, nor in impedance, nor in any other specification. It is not to mention that capacitance almost always is very flexible parameter and precision of value is necessary only in case of caps use for filtration. However, capacitance doe not filter itself but only along with impedance, so it always possible to play with impedance to moderate the required value of capacitors. Therefore I do not mind the caps to be cheaper and only at fixed values.

Now about the threshold between rational and irrational. Duelund makes huge 300uF caps, 25 kilograms with 1 kilometer of metal in each.  I am sure it is insanely expensive but I question if it is justifiable. It is imposable to control tension and properly damp 1 kilometer of foil in those caps. I never heard them of course but I would very much would like to see those 300uF Duelund caps compete with regular commercial grade electrolytic that would be 1000 times smaller and 1000 less expensive.  I have a feeling that Duelund will not be effective, particularly if electrolytic is used with active basing.


OK, let to look from a different perspective – my favorite perspective – cost bur solution. The 300uF, low voltage Duelund caps probably meant for speakers crossovers. Those values in speakers crossovers are useful only for low-passing of bass (the area where active based electrolytic destroy any competition) . So, what Duelund offers for low-passing of bass? A $2000 capacitor? Does anybody feel that the Duelund’s solution price-wise very much competes with idea of multi-amping? Do anybody understand that using a dedicated amp for bass and a few nF capacitor in amp’s input is order of magnitude more interesting solution then to use a “magic caps”?

Well, I am not against of what Duelund offers but I would call to some sanity in this subject. Their small, up to 5uf caps might be good but why shell they be expensive?

The caT

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