Replacing caps in an old speaker system. Should I use a higher value here?

[Delicieuxz]

I'm recapping an old Creative Labs / Cambridge speaker system / subwoofer. At 4:33 in this video, the person looking at what he says are the speaker caps in the system says they are 470 uF, and that he'd use much larger caps if he was building it.

https://youtu.be/1LRIzePlma0?t=273

I'm wondering if I should use something larger for the recap job, and what using larger caps will do for it.

Would 680uF be good value to try in place of the 470uF originals?

[sam_sam_sam]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

Where is this capacitor located at power supply rail or somewhere else because it might make a difference in performance

[Delicieuxz]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

Where is this capacitor located at power supply rail or somewhere else because it might make a difference in performance

Unfortunately, I don't know. My circuitry knowledge extends little beyond soldering and following traces. Would there be an obvious way to tell, or any risk, if I just installed 680uF caps, and then tested it by using it normally?

[sam_sam_sam]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

Post some pictures of the circuit boards in this device and might be able to help you out

[momaka]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

I'm recapping an old Creative Labs / Cambridge speaker system / subwoofer. At 4:33 in this video, the person looking at what he says are the speaker caps in the system says they are 470 uF, and that he'd use much larger caps if he was building it.

https://youtu.be/1LRIzePlma0?t=273

I'm wondering if I should use something larger for the recap job, and what using larger caps will do for it.

Would 680uF be good value to try in place of the 470uF originals?

If these are for the front L/R and rear L/R speakers (and it looks like they are), I say don't bother. Reason being is that this system has a subwoofer already, which means the sub should handle all of the bass / low-end audio frequencies. Upgrading the speaker output coupling caps only matters if the system doesn't have a subwoofer and you want to get deeper bass / lower high cut-off frequency. At around 6 min. into the video, you can see the datasheet for the audio amp IC that handles the small speakers has 1000 uF output coupling caps. But again, that's if you want "full range" audio frequencies going to the speakers. In the case of this speaker system, the sub should be handling all frequencies under ~120-150 Hz... so 470 uF coupling caps for the small / surround speakers is OK if they are rated for 4 Ohms or more. With 4-Ohm speakers and 470 uF, the low-cut frequency will be ~85 Hz. I'm pretty sure there is also some kind of a high-pass filter for the small speakers before the power amp IC, so changing to higher capacity output coupling caps may not even change how the system works at all.

If you do want to upgrade the capacity on any of the caps, do that for the main input cap that filters power from the transformer. And possibly any signal coupling caps for the subwoofer amplifier IC... but be careufl! - Find a datasheet for the sub IC and see the suggested values in the app circuit. You have to be careful about increasing the value of certain caps, otherwise the amp IC could become unstable or give an annoying popping sound at power On and Off.

[Delicieuxz]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

Post some pictures of the circuit boards in this device and might be able to help you out

If these are for the front L/R and rear L/R speakers (and it looks like they are), I say don't bother. Reason being is that this system has a subwoofer already, which means the sub should handle all of the bass / low-end audio frequencies. Upgrading the speaker output coupling caps only matters if the system doesn't have a subwoofer and you want to get deeper bass / lower high cut-off frequency. At around 6 min. into the video, you can see the datasheet for the audio amp IC that handles the small speakers has 1000 uF output coupling caps. But again, that's if you want "full range" audio frequencies going to the speakers. In the case of this speaker system, the sub should be handling all frequencies under ~120-150 Hz... so 470 uF coupling caps for the small / surround speakers is OK if they are rated for 4 Ohms or more. With 4-Ohm speakers and 470 uF, the low-cut frequency will be ~85 Hz. I'm pretty sure there is also some kind of a high-pass filter for the small speakers before the power amp IC, so changing to higher capacity output coupling caps may not even change how the system works at all.

If you do want to upgrade the capacity on any of the caps, do that for the main input cap that filters power from the transformer. And possibly any signal coupling caps for the subwoofer amplifier IC... but be careufl! - Find a datasheet for the sub IC and see the suggested values in the app circuit. You have to be careful about increasing the value of certain caps, otherwise the amp IC could become unstable or give an annoying popping sound at power On and Off.

Good info. Thanks!

Here are a bunch of photos I've taken of the two boards:

[Delicieuxz]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

Here's an update:

I initially replaced all the electrolytic caps other than 4 non-polar 1uf 50v caps, as I accidentally ordered polar 1uf 50v caps. I ordered some Nichicon NP 1uf 100v caps separately, and I installed them when they arrived.

Both after initially replacing all the electrolytic caps other than the 1uf ones, and after, the speaker system sounds great, without the buzz and hum that it had before. After later installing the 1uf caps, it seems to me the system has far less bass on tap, and the bass seems more restrained, in general. There's still enough bass, overall, but I think I have the bass control turned up almost 1/3rd more than it was before I replaced the 1uf caps.

It's hard for me to be sure exactly what the difference is, since I can't A/B before and after. But this is an impression I have.

The speaker system sounds fantastic, regardless, and all the unwanted noise and interference is now gone from it.

[stj]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

what caps did you buy?
make/series?

not surprised throwing out the jun-fu 85' caps improved it.

[Delicieuxz]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

what caps did you buy?
make/series?

not surprised throwing out the jun-fu 85' caps improved it.

I didn't pick the brand, but ordered from a local store that I trusted would have decent caps. It looks like they're a mix of different brands (same brand per cap value): Nichicon, Rubycon, KEMET, KMG, and one that just has a diamond shape on it in addition to its stated value.

[andrewsawesomr]

Re: Replacing caps in an old speaker system. Should I use a higher value here?

The calls marked "KMG" are probably from Nippon Cheni-Con / United Chemi-Con