Crossover upgrades and new tweeters

You replace it because film and foil caps are superior.

Now you need some serious burn in time ...after 200 hours my 10's were a whole new beast! they well just keep getting better for awhile. ENJOY!!

Congrats Randy. I am waiting for parts to arrive for my 2As. Hope I have similar good news

My crossover upgrade sounded great right from the start. I didn't experience any ups or downs in performance over time like some have reported.

Dayton film caps for the 20uf parts. A friend is sending me the 130s, so I'm not sure if they are Mylar or electrolytic. Soon come, mon. My setup is different than yours.

Unsurprisingly, not everyone agrees with Crites. I did not hear changes--good or bad--that I can put down to "break-in" when I replaced the caps in my 1Bs. They just sounded great, instantly, and still do.

http://www.critesspeakers.com/frequently-asked-questions.html

Q: Do components have a break-in time?

A: Some do and some don't. Capacitors would be a definite NO. Let's look at this one a bit.

You have new good quality capacitors installed in your crossovers. Capacitors have exactly two qualities that effect the sound of your music that goes through them. Those are capacitance (what we use them for) and ESR. ESR is the sum of all other qualities of a capacitor other than capacitance expressed as an Equivalent Series Resistance. ESR is a bad thing. Good caps have ESR so low it is barely measurable, on the order of a couple of hundredths of an ohm. ESR is made up of stuff like the resistance of the leads and their connections to the foil inside the capacitor or stray inductance or dielectric absorption.

So, we put our new caps in the crossovers. These new caps are right on the capacitance value the design calls for and the ESR is almost unmeasurably low. What exactly of these two qualities do you expect to change with break-in? And if either of them changed, why would you expect the sound to get better since the only way they could change is to go away from the "perfect" values they had to start with? I hope any caps you use in your crossovers are good enough that they do not change at all for many years of use.


http://www.audiokarma.org/forums/showthread.php?t=637954

I have experienced what F1 touts. Mine sounded somewhat better from the start but over time the the presence and clarity has increased. On the 1C the 200 hours burn was an extended time due to fact they were used infrequently compared to the 2.3 TLS everyday use.

When I first got my crossovers back from Dave I thought they sound a lot better from the start, then I started a burn in program of 12+ hours a day and after 100 I listen again and the thing that changed the most was the high's but they were new RDO-198 tweeters so maybe they were burning in too. then I listen again after 200+ etc...
To me I plainly heard improvements along they way, now I did have some fairly new analog cables that sort of got burned in also.

finished my SDA2A refurbish last night. New RDO194 tweeters, new capacitors, jumped the polyswitch. Did not touch the resistors, as I assume they don't deteriorate. The speakers were in good shape before I started, so difference is subtle. Better clarity and definition in the high end. Tried the tweeters before re-capping and they sounded duller than the SL2000s, but back to quality with new caps installed. The soundstage is more expansive and seems wider than before. so far so good. only have listened briefly.

They should only be stuffed above the passive area of the cabinet. And the stock fiber fill is plenty.

As for not doing the resistors, why not? It is really cheap insurance. And they also make improvements of their own. Resistors are the part of the crossover that heat up and cool down. These thermal effects will cause deterioration of the resistors ability to dissipate over time.
There is also the consideration of tighter tolerances in these new resistors.

Just food for thought.

ZLTFUL: Interesting that you think that. I spoke with a Polk tech advisor who says it would make no difference to change the resistors. But if I was to do that, I don't see 2.7ohm 10% 5W resistors online anyway. And thanks westmassguy for the fiber fill answer. it seemed odd that the cabinets were so starkly empty.

The suggested Mills parts are significantly better at dissipating that thermal load with much lower chances of failure.

And more importantly, the lower inductance of the Mills resistors.

I spoke with a Polk tech advisor who says it would make no difference to change the resistors.

Did you ask this person if they have ever modified a crossover? If they have ever used something other than a sand cast resistor?

F1 next time you are in Denver stop by and give a listen. I'm sure you will have lots of good ideas. ZLTFL I did not see the correct Mills resistors in my search. I'll look again. I did not grill the Polk tech, but on 2 different calls to them I got the same advice. I really have no other SDAs to compare to, but these sound darned good. I bought them from a guy who had them in a box, purchased here in Denver, and they looked like they did not get much use which is amazing for a 1986 item. My other speakers are from the same era, which I purchased in Miami; Energy pro22. They were awesome but the tweeters dried out and died every few years. I gave up on paying for rebuilds as they are no longer available. At the time I purchased them it was either the Energys or the Polk SDAs, so I got em both now.