"Parts upgrade" on crossovers -Any experiences?

Tireguy, thanks for the reply. I know the KEFs have matched drivers and crossovers. I might at the minimum replace the push button connectors with quality binding post and the wire that goes from the board the the new binding posts. So far I am very happy with the sound (after all, KEF supplied most of the drivers for the Rogers and Spendor BBC monitors). I might try to make me a board adhearing to the factory schematic (and bypassing the overload protection circuit). This way I can simply keep the stock xovers intact and be able to put the KEFs back to how they cam. I'll check out audioasylum.com's tweaks section.

I lean pretty strongly towards--don't mess with it, if it isn't broken. Cross-overs are voiced for the speakers. In most cases, even with improved parts and wires, you will usually take 1 step forward and 3 steps back. I could go into examples--but everyone is different. Suffice to say, that even a simple wire upgrade in a speaker can actually give you much worse results because the crossover was voiced for the wire used and thus an "upgrade" causes a loss of "magic". If you do decide to experiment--save the old parts--and label where they go. Also--I don't necessarily feel this way about amps and other electronics because the do not have the "voicing" so to speak. Speakers are a transducer and thus the synergistic nature of the cross over and drivers (and wiring) can not be broken down into confined specifications of what is supposed to do without the other. In electronics--such as amplifiers--the power supply (or other subassemblies) can be broken down into specifications for ripple, noise, etc--which can be independently improved by better parts--i.e. capacitors etc.

I totally agree with Rives. It is very difficult, almost impossible to change crossover parts and maintain the speakers voice. You might get improvement in one area only to make the speaker un listenable overall.

I post this from experience, having rebuilt the crossovers on three high quality speaker systems with the Snell Type A being the biggest disaster.

The Snell I "ruined" simply had the wire replaced and swapped caps with EXACTLY same value, but better quality. The sound was so shrill they had to be returned to the factory to be restored to stock. Luckily this was many years ago when Peter Snell was still alive, so he bailed me out. (Bless him!) he was a wonderful person and a good friend.

Many of the "problems" that one runs into when modifying speakers are that the "high grade" replacement caps are not oriented with the proper "polarity". While some will question the validity of a comment that states that non-polarized caps can be installed with the incorrect polarity, please read on.

Caps have an inner winding and and outer winding. As such, one can orient two caps, which look the same and have the printing facing the same way, in the opposite directions within identical circuits. The end result is a fuzzy mess with a lack of focus and cohesiveness. Another common side-effect is blurring of imagery and an increase in harshness. As such, one should go to the trouble of "polarizing" the caps so that they all share common directionality prior to installation. Bare in mind that, just because the labels / printing on the caps are all facing the same direction, the caps may not share common polarities / connections inside the cases. There is a trick to finding the correct polarity and once you do this, you will instantly know what i am talking about. One can see the differences in polarity on a scope once you learn the "trick".

Once this is done, you will find that having all of the caps polarized in one direction will sound different than if you reverse the polarity of all of the caps within the circuit. In such instances, there is no right and wrong, so choose which orientation sounds best to you.

On top of that, caps used within speakers can take a long time to fully break in. Due to the very dynamic ( read this as being "sporadic" or "non-steady state" ) signals that are applied to them, the caps don't really "form" like those that are used in power supplies or line level signals that are relatively constant. As such, one can "form" the capacitors prior to putting them into a circuit using a signal generator of high amplitude and speed the process up drastically. Once you've done this, the differences in "sonic polarity" with the cap facing one way in the circuit and reversed will become more evident also.

Besides all of this, every wire and resistor will impose their sonic signature into the circuit. As such, it is best to use wires that you already know sound good with those speakers and to keep the legs of any component ) cap, resistor, etc... ) as short as possible and make a good mechanical connection prior to applying solder. In other words, the connection should be solid prior to applying the "electrical glue" aka solder. This helps to minimize the influence / sonic characteristics of the solder. If you don't do this, the solder becomes the conductor rather than the actual leads on the components.

Other than that, each product is built to a price point and most engineers / designers have their own likings. If you like a product and it was truly designed to be as neutral as possible, adding passive components that are even more "transparent" by nature will only improve the product ( if done correctly ). Otherwise, taking a product that has a "built in flavour" aka "colouration" and trying to hot-rod it can end up in something VERY different. Whether or not it is an improvement is up to you as an individual and how much you liked that specific colouration. Sean
>

Very interesting - as I posted in a recent thread, I had to have an under-spec'ed resistor that went bad "upgraded" on one of my Thiel 2.2's by the factory, whose tech stated that this particular resistor (at 1/4 watt) had caused many previous problems on this model. He just threw what he happened to have lying around (of the same ohm rating) in there instead - a 5 watt resistor of a clearly different type, and also gave me another one to install in my good speaker as a preemptive measure (he admitted that this wattage rating was actually overkill). I haven't done that yet, and this thread gives me pause. Maybe I should call back down to Thiel and see if I can speak to the head honcho himself by way of doing a little more research before breaking out the soldering iron. My one reassuring indicator so far - since I haven't yet re-broken in the fixed speaker, which also required two new drivers - is that the tech performed a quality-assurance anechoic test on the repaired speaker, and said it measured better (by which he presumably meant flatter, or within a tighter tolerance) than most examples of the model.