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In the Forum: Analog Playback
In the Thread: The K&K SE hybrid phono stage: a report
Post Subject: Again, use “price” as a design toolPosted by Romy the Cat on: 2/19/2010

It is nothing to do with Wisdom.  It is my principle of application of “cost” as a common sense design tool. I do not bitch that Duelund caps are expensive. I just try to find a rational solution for using them that would embrace their price. My argument is that with $1000 per 1uF the Duelund caps not useful. Let me show it to you.

The high quality super-expensive cap makes since to use in first order high-pass filters for HF drivers. Let pretend that we have 8R driver then at 2.000Hz we need 10uF per channel, at 500Hz we need 40uF per channel. No one would suggest $80K of capacitors in this filter. With 16R driver and crossover point of 1000Hz we have 10uF. With lower voltage of caps, not he 630V, the cost would go 2-3 time lower, so I presume that 20uF of 200V would be around $3-$4K. With this cost of capacitors in filter the total coast of the solution begin to be competitive with a cost of multi-amping solution with DSET.

Let say that a cost of HF DSET for the same driver will be $5K-$7K. In this HF DSET for filtration purpose it might be used a small fraction of mF and very low voltage cap (it might be Duelund) that would be MUCH better than any larger Duelund cap. It is not to mention that in multi-amping it might be used the RL shunt filtration that would be light miles away and superior then ANY capacitive filtration. The cost of multi-amping and Duelund C-filtration is competitive but the multi-amping   has so much more advantages!

So, my point is that there is only restricted cost in speaker-level crossover. When this cost goes up to much (like in case of using Duelund caps) then here is always a multi-amping DSET consideration as an alternative. An multi-amping DSET has disadvantage to be costly but if one already waste time for better caps then why don’t do it properly and to invest the virtually the same amount of money for a pair of extra DSETs?

Romy the Cat

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