What Capacitor Is Better ?

[ka7niq]

I changed them to the low ESR ERSE Polycaps, now the mids seem too hot.

I see, still I would run them for a bit, and see if your ears or caps break in. I have seen many threads where 30ppi open cell foam is inserted in the horn to soften the sound when used with SS gear.

Although sceptic I tried the foam on a pair of stock cornwalls with metal horns, and found the results to be positive. The foam is filter foam, and used by speaker manufactures like Mcintosh for speaker grills, and over microphones as wind screens.

Foam is also used on these speakers.

http://www.gedlee.com/

YES !

Maybe the caps will break in ?

I will look into the foam.

Oh, BTW, the woofer cap called for a 10 percent 68 UF, I used a 5 percent 65 UF, hoping that if I made an error, it would cause the woofer to play UP a little higher into the mids, avoiding a hole.

I think I noticed the new cornwall 3 seems to have a higher woofer crossover by 100 hz, but may be mistaken.

[Guest David H]

Oh, BTW, the woofer cap called for a 10 percent 68 UF, I used a 5 percent 65 UF, hoping that if I made an error, it would cause the woofer to play UP a little higher into the mids, avoiding a hole.

I think I noticed the new cornwall 3 seems to have a higher woofer crossover by 100 hz, but may be mistaken.

The Cornwall 3 is crossed higer than ver I or II , however I do not think using the smaller value cap made any signifigant change. But if you are concerned, install a 3uf cap in paralel with the 65, and give it a listen.

Typically if the mid is to hot, it is due to interaction between the tweeter and mid causing a bump in response.

Dave

[ka7niq]

Oh, BTW, the woofer cap called for a 10 percent 68 UF, I used a 5 percent 65 UF, hoping that if I made an error, it would cause the woofer to play UP a little higher into the mids, avoiding a hole.

I think I noticed the new cornwall 3 seems to have a higher woofer crossover by 100 hz, but may be mistaken.

The Cornwall 3 is crossed higer than ver I or II , however I do not think using the smaller value cap made any signifigant change. But if you are concerned, install a 3uf cap in paralel with the 65, and give it a listen.

Typically if the mid is to hot, it is due to interaction between the tweeter and mid causing a bump in response.

Dave

Well,, I have the titanium diapraghms in thses tweeters, I wonder if the titanium diapraghms have slightly less efficiency, making the midrange overly foreward ?

I still have the stock diapraghms, and could always slap them back in easily enough.

[freddyi]

hey Herb - do I see an autoformer rotary adjustment attenuator in your crossover?

[Guest David H]

Freddi, that is a Rat Shack speaker in wall volume attenuator, I did some testing with them, and seems to work good for the tweeter.

I used those on a few crossovers, then had my own custom wound and potted to ease mounting and eliminate vibration.

These are 8 ohm 10 watt transformers.

Dave

[Guest David H]

Here is a pair of attenuators mounted I sent to JWC.

[freddyi]

nice custom attenuators - are their mounting cases plastic? - do they handle more power lower than Klipsch autoformer? I've run a $10 stereo Belkin autoformer as a CD player volume control - not much inductance but still nearly flat at 20.

ka7niq - here's a nifty page on a 2.2uF cap's failure - its called a "foil" cap but I believe its metallized:

http://www.amplifier.cd/Technische_Berichte/defekter_Folienkondensator/failed_foilcapacitor.htm

[Guest David H]

do they handle more power lower than Klipsch autoformer?

No, the are only 10 watt autoformers, not sure how much power the klipsch T2A will handle.

are their mounting cases plastic?

Yes they are potted in plastic.

Here is a pic of the bare transformer.

[Deang]

ESR of a good polyester measures in the 100ths of ohms. The ESR of a good polypropylene measures in the 1000ths of ohms. If the ESR of an existing capacitor is high, it means the cap was garbage to begin with, or has declined in performance over time.

If it sounds too hot to you, either attenuate, or don't listen as loud. The answer is not to put crappy capacitors back into your crossovers.

Experiment with placement -- move the speakers back a bit to bring up the bass and restore balance.

[hklinker]

hey Herb - do I see an autoformer rotary adjustment attenuator in your crossover?

freddyi-

Yeah, those are the Rat Shack ones Dave mentioned. He gave me the idea when I was trying to tame my overachieving K-77's. I have the option of mounting them there, or on the back of the speaker where I installed a binding post cap. Right now I stuck them in line on the board, using rubber gaskets and a little epoxy to fasten them. My APT-50's are not as "hot" as my K-77's so I have them cranked full (no attenuation).

They are $20 apiece and are rated at 50W, a well built autoformer that does the job for me.

Herb

[ka7niq]

ESR of a good polyester measures in the 100ths of ohms. The ESR of a good polypropylene measures in the 1000ths of ohms. If the ESR of an existing capacitor is high, it means the cap was garbage to begin with, or has declined in performance over time.

If it sounds too hot to you, either attenuate, or don't listen as loud. The answer is not to put crappy capacitors back into your crossovers.

Experiment with placement -- move the speakers back a bit to bring up the bass and restore balance.

THAT is the question Dean, were the stock Mylar Caps "garbage" to begin with, or did they degrade over time ?

HTF does plastic film "degrade" ?

Electrolytics, sure, but I am having a very hard time accepting that a Mylar Cap can degrade.

Bob told me he has measured these old mylar caps, and saw high ESR.

I trust and believe Bob Crites.

However, w/o a stock, new Mylar cap to compare it to, perhaps the high ESR he measured is the inherent value of the cap ?

If so, then perhaps Klipsch took this high ESR into account in the crossover design ?

[djk]

"HTF does plastic film "degrade" ?"

It's how the leads are attached to the film that fails (high ESR).

I think you would be better off to use the best cap in the midrange circuit and add a small resistor, rather than fool around with 'lossy' caps to get the balance you want.

[ka7niq]

ESR of a good polyester measures in the 100ths of ohms. The ESR of a good polypropylene measures in the 1000ths of ohms. If the ESR of an existing capacitor is high, it means the cap was garbage to begin with, or has declined in performance over time.

If it sounds too hot to you, either attenuate, or don't listen as loud. The answer is not to put crappy capacitors back into your crossovers.

Experiment with placement -- move the speakers back a bit to bring up the bass and restore balance.

I found the "problem" Dean !

There IS no "problem" at all!!!

I moved the Cornwalls into my main system with much better amplification, replacing the B&W 801's, temporartily.

The "problem" is the re furbished Cornwall 2's do not LIKE my Yamaha RX V1.

They sound like a totally different speaker in my other room, with a better source chain.

However, I do not like them as much as my 801's, and their color does not match the decor in that room.

The room my 801's are in is on the small side, and the 801's are plenty loud and dynamic in there.

So, I will reluctantly say goodbye to the refurbished Cornwall 2's, as they have no place in my world any longer.

For the sake of this thread, the ERSE Poly Caps worked very well in the Cornwall II's, and so did the Crites Titanium Diapraghms.

The refurbished Cornwall 2's sound splendid, there is nothing wrong with them, the Yampah RX V1 and them just dont like each other.

Someone will get a really nice sounding speaker, with much of the refurbishing already done for them, assuming they have a system/room the Cornwall 2's like ?

I find it amazing how the midrange forewardness disappeared, just by changing amps/rooms.

If I did not have B&W 801's, and I was not so "married" to the Yamaha DSP system of the Yamaha RX V1, I would keep the Cornwall II's.

[freddyi]

"HTF does plastic film "degrade" ?"

It's how the leads are attached to the film that fails (high ESR).

I think you would be better off to use the best cap in the midrange circuit and add a small resistor, rather than fool around with 'lossy' caps to get the balance you want.

Hi DJK - which caps are known or assumed to be "good" with regards to lead termination? - need 12uF minimum doing type A (or double if battery biased) -- -for stock Heresy I considering 2uF Theta foil - any other caps to look at?

[ka7niq]

"HTF does plastic film "degrade" ?"

It's how the leads are attached to the film that fails (high ESR).

I think you would be better off to use the best cap in the midrange circuit and add a small resistor, rather than fool around with 'lossy' caps to get the balance you want.

Thanks Dennis.

I used good ERSE Poly Caps, and they will stay there.

Nothing is wrong with the Cornwall 2's, except they dont sound very good with my Yamaha RX V1.

In my main system, I currently have the Ashly FET 500 with new supply caps running the 801's, and a Dared Tube Preamp with a Tube DAC.

The Cornwall 2's sounded great, in there, I just prefer the 801's.

[freddyi]

"tone controls for the audiophile" can get to be an expensive version of Goldilocks - trying multilple amps, dacs, cap swaps --- putting a small value resistor in series with a cap seems like a cheap and effective way to tune - within limits- might not be easy to get to in some networks & if one doesn't mess up the cap's lead then that might be worth trying - a question for DJK - can one add a small value cap at the driver and sometimes get the wanted effect? - if so are we talking 0.5-2 ohms range?

[Deang]

...might not be easy to get to in some networks & if one doesn't mess up the cap's lead then that might be worth trying

You don't have to get to the network, you can connect the resistor at the driver side. Some people have issues with series resistors, but they do have the advantage of not adversely affecting the impedance.