Crossover Caps: Electrolytics vs. Non-Polar?

[ElectroKid]

Hi,

Want to change bust piezos in GF-767 to real tweeters (Toshiba CRT TV 4-ohms 2inch).
The GF-777 service manual states the caps are Non-Polar.
Also I plan the same mod for the Aiwa CS600 piezos...
Should I use the common electrolytics for crossover as I read they are for DC applications (will block current in one way..) while audio signals are AC ?

Would like to hear your thoughts, is it important to get non-polars?
Tried using 4.7uF electrolytics and noticed that I get low volume, the tweeter does not shine enough to me, then changed to higher capacitance say 100uF and they get better but is it good for overall frequencies to stay like that?
Is it worth getting special 4.7uF Non-Polars, will they improve anything at all?

 

[MyOhMy]

Ha, ha, ha!! You guys, eh? All that Tech Talk went straight over my lil, ol' head! I think this is speaker talk but I haven't got a clue!!! You never know, one day, if I live another hundred years...................

 

[Cpl-Chronic]

Hi,

Want to change bust piezos in GF-767 to real tweeters (Toshiba CRT TV 4-ohms 2inch).
The GF-777 service manual states the caps are Non-Polar.
Also I plan the same mod for the Aiwa CS600 piezos...
Should I use the common electrolytics for crossover as I read they are for DC applications (will block current in one way..) while audio signals are AC ?

Would like to hear your thoughts, is it important to get non-polars?
Tried using 4.7uF electrolytics and noticed that I get low volume, the tweeter does not shine enough to me, then changed to higher capacitance say 100uF and they get better but is it good for overall frequencies to stay like that?
Is it worth getting special 4.7uF Non-Polars, will they improve anything at all?

DO NOT USE polarized caps. They MUST be non-polarized & polyester film are best for sound quality. Electrolytics tend to have a harsh brassy so0und that is impressive at first but will create ear fatigue after extended listening sessions. Also, electrolytics can change value over time which will smear the stereo imaging. I've done all kinds of speaker mods for the 777 series & poly-film caps work the best & don't have the same short-falls of electros.

Hope this helps

Cpl

 

[ElectroKid]

thanks Cpl,
do u recommend 4.7uF as spec?
or you too noticed it lowers the volume and had to increase the uF?

 

[ElectroKid]

DO NOT USE polarized caps. They MUST be non-polarized & polyester film are best for sound quality. Electrolytics tend to have a harsh brassy so0und that is impressive at first but will create ear fatigue after extended listening sessions. Also, electrolytics can change value over time which will smear the stereo imaging. I've done all kinds of speaker mods for the 777 series & poly-film caps work the best & don't have the same short-falls of electros.

Hope this helps

Cpl

polyester capacitors of the rectangular type should be ok?
View attachment 22051

 

[stosoorok]

In audiophile territory, there are German Mundorf caps and Russian Teflon caps highly recommended, but maybe too overkill for old boombox. BTW, I just got the 777 and this work is ahead of me! New topic goming soon!

 

[Cpl-Chronic]

thanks Cpl,
do u recommend 4.7uF as spec?
or you too noticed it lowers the volume and had to increase the uF?

I would try both 4.7's & 6.8's. The 6.8's will bring the x-over point down further into the midrange & worked well for me. I noticed on the 777 a gap in the upper midrange that caused the tweeters to be a bit muted & the stereo imaging suffered, making voices & guitar muddy.

Of course, your ears will tell you what is best for you.

Cpl

 

[BoomboxLover48]

Could this be the reason my left channel is a little muted on tweeter on one of my 777s?
Those non polar caps hardy fail. It seems like I need to change both and see the difference.

I would buy both both 4.7's & 6.8's like you suggested Cpl-Chronic! Thanks

Now the bass on my left channel is more than the right but the treble is low. The right channel is good on bass and treble is kind of okay but not there.

Hopefully the whole issue is with the nonpolar caps right?

 

[Cpl-Chronic]

It's worth a shot & it'll only improve the sound regardless of whether that is the issue you are having. Of course, measuring the DC resitance of both tweeters will tell you if 1 is shot or shorting out the voice-coil.

Cpl

 

[BoomboxLover48]

It's worth a shot & it'll only improve the sound regardless of whether that is the issue you are having. Of course, measuring the DC resitance of both tweeters will tell you if 1 is shot or shorting out the voice-coil.

Cpl

I had a 10 uF /50V non polar laying around and hooked it up but didn't show any difference. I never thought those tweeters fail...will check soon.

 

[BoomboxLover48]

Checked the tweeter and it read 4.0 ohms.

I re-soldered the old non polar back and now it all works fine!

It was a bad solder joint.

Now both channels work fine and no excess bass on the woofer.



I have already ordered the 6.8uF pair and will replace that when it comes in.

Thanks Cpl!