Chorus-II xover

[leok]

I've made one (well 1 1/2) change to the Chorus-II crossover. Thanks to deang and mike stehr for thier help and warnings.

The high end of the mids seemed a little messy so I thought I'd replace that little 6uF electrolytic. See attached picture. The little silver cap is replaced by the big cap-farm.

The cap-farm consists of 4.7 and .33 uf Jensen foil pios and a 1uF metalized polyprop. (that adds up to 6, I think).

The good news was the high end of the mid was cleaner, but there was too much mid altogether. I finally decided the electrolytic ESR was necessary so I added a 0.15 Ohm resistor in series with the cap. Boy! It doesn't take much to make a mess out of a c3-way crossover.

Anyway, now it sounds very good .. better than stock .. definately cleaner, but so unforgiving of flawed source material.

The Chorus-IIs ar really growing on me, esp with the cleaned up (and level-adjusted) mid. A warning to those who consider simple cap improvements: it might not be as easy as it looks. Similar to what Dean and Mike found with inductors.

leok

[Audio Flynn]

I too find the Source material to be the weakest link in the listening to the Chorus II.

Sony Classical matering is far inferior to Duetch Gramophone or Harmonia Mundi.

On old WHO tunes with Daltry belting out the vocals you can hear the microphone diaphram overdriving. That sounds really bad. And have never heard it sound so bad before.

VPI cleaned vinyl records also sound faboulus compared to a conventionally cleaned one.

[Deang]

Yes, but inductors are little demons in disquise, and changing up the DCR in the wrong part of the circuit can destroy the voicing. Changes in DCR between like inductance values are much further apart than changes in ESR between like value caps. If one compares the ESRs of quality plastic caps, whether they be metal or film -- the differences are miniscule. Should we really get excited about 3 or 4 mOhms? Even comparing plastic types to PIO, it's usually less than 20 mOhms. I'm just not convinced that the differences in ESR alone account for the varying sonic signatures of like value caps constructed of different material. We may never know why caps sound so "different", but we know they do.

Here is something interesting: When Regnar (contingent of original Dahlquist technicians) put together the capacitor upgrade kit for the DQ-10, they found that replacing the mylars with cheap metallized polypropylenes turned the DQ-10 into a screeching banshee, and they had to completely re-engineer the board to restore the "original" voicing. Not one cap value remained the same when they were done. My personal experience with the upgrade kit was that it turned a wonderful speaker into a mediocre one -- and they certainly didn't sound like they had been voiced to "original". My solution was to go back to the original values using quality caps. My solution is the right one -- but it is expensive.

There is definitely a difference between a $5 cap and a $20 cap, and with exception of the Auricaps and ICWs, I will never use a metallized polypropylene again.

I would take that 1uF cap off the farm and drop it into the septic tank.

[leok]

Dean,

The cap I replaced was a non-polarized electrolytic. I've seen ESR specs for those things at over an Ohm. I guessed at 0.15 Ohms for the frequency range in question, and that much resistance made a very big difference. I don't know what ESR Clipsch actually expected from the device, or if the caps, from lot to lot, actually delivered what was expected. I agree with you about the metalized polyprop, but that cap is pretty safe where it is and I've had good experience with that particular Cornell Doublier model.

I do expect less of a surprise when I swap out the tweeter caps, for exactly the reason you mentioned .. the ESRs will be very close.

leok