Crossover improvements

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jeffreybehr

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Crossover improvements
« on: 4 Jun 2011, 02:13 am »
I'm the first to admit that RV has managed to build a truly-5-star speaker system.  That he has achieved that with a crossover network full of 2- and 3-star parts is a tribute to his skill and artfulness.  However, I am indeed an incorrigible tweak, and I don't much like the sounds of DynamiCaps.  While deciding that the main caps in series with the MR and treble drivers* are too high in value and low in volume to change, the DynamiCaps bypasses aren't, so I replaced them.  A pic of the original x-over is here http://www.audiocircle.com/index.php?topic=94855.0 .  The principle space restriction is the height of the board and parts, since it lives in the c.-two-inches-high space between the bottom of the upper-frequency 'head' of the system and the top of the bassbox in the bottom of the system.  There's not even room around the x-over for larger caps dangling from the board on long leads. 

Here's a pic of the x-over overall.  Visible are the three 0.1uF SoniCap Platinum (Teflon-film) caps now residing about where the DynamiCaps used to, and the three MultiCap RTX ('styrene) caps atop the bank of WIMAs in the MR filter.

I had replaced the D'Caps weeks ago, and the Platinums are well broken-in.  Since they were already installed, I just joined the leads of the RTXs to those of the Platinums.  Lead extenders are 23g. Neotec OCC-silver, doubled.

Here's a closer look at the input end of the board.


...and the left end of the RTXs.


The systems sounded great with all-original parts and, I think, a little more transparent with the Platinums.  I hope they'll sound even-more transparent with the RTXs added.  We'll see.   :D


* The tweeter has a pair of 4.7uF WIMA 'propylenes (= 9.4uF) bypassed with a 1uF DynamiCap on each of the positive and negative poles, while the MR has a 22.85uF series/parallel combination of WIMA 'polyesters and 'propylenes, bypassed with a 1uF DynamiCap.
« Last Edit: 27 Sep 2015, 07:28 pm by jeffreybehr »

jeffreybehr

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MORE Crossover improvements
« Reply #1 on: 11 Jun 2011, 08:08 am »
After doing the RTX-installation work, I thought I might to able to get a much-larger-diameter 1uF SoniCap Platinum (Teflon-Film) cap in the cavity to the left of the 3 RTXs and occupied partially by the bunch of light-blue resistors.  I was right; it fits and is now the sole bypass for the MR-driver WIMA filtercaps.  (The midrange is the most-important band in music, and I simply wanted a better cap than the RTX/small-Platinum combo.)

This is an overall view...

...while here is a closer view.


Because this is the 3rd time I've been inside this assembly, things aren't as neat as I'd like nor as neat as I'd do if I were starting over on fresh boards.  But it'll do.   :)

Teflon-film caps require hundreds of hours of break-in before they sound their best; I'll let you know if I think the system sounds any better in a few weeks.

Meles

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Re: Crossover improvements
« Reply #2 on: 10 Feb 2015, 11:58 pm »
How did this turn out? What are all the little black boxes? I'm actually plotting some RV no no's with my vandersteen 4a crossover. Your 5s appears to have no electrolytic capacitors I see. At some point I plan to battery bias my 4a crossover and do in most of the electrolytics (I've actually got all the parts.)