Hi I am looking for some advice regarding upgrading the 7 X 4700uf 63V capacitors in my Power Amplifiers. What are the best upgrade replacement capacitors I should be considering for this amp? I have been looking at the Nichicon KG line but is there better I could consider?
7 caps? 3 per rail and one for something else?
That amp is 120W/ch into 8 ohms, 400W bridged (so 200W/ch into 4 ohms). Suggests peak load currents of 20A for bridged 8 or stereo 4, 11A for stereo 8 ohms. Gives an idea of the ripple current rating.
That amp is 120W/ch into 8 ohms, 400W bridged (so 200W/ch into 4 ohms). Suggests peak load currents of 20A for bridged 8 or stereo 4, 11A for stereo 8 ohms. Gives an idea of the ripple current rating.
Stick to tier one brands. I'm sure there's a good list on this site. (nichicon meets this criteria)
Look for high ripple current rating and low e.s.r.
There's usually no harm (and some benefit) to be had moving up to the next capacitance rating, but keep in mind that all things being equal, e.s.r. will increase too, so it's a balancing act. In the end enough is ... enough.
Match the form factor to what you're replacing (most likely snap in 10mm, but watch for physical dimensions too)
High temp (105C) versions typically have longer life under the same conditions, but IMO it's largely academic, and they may suffer in other specifications. Smoothing 50/60Hz for home audio applications these caps will be running well within rating and should last decades without much drama (I tested some bulk caps recently out of a Hitachi HA4700, 37 years old, nothing special. Still within specification.)
Finally... price, personal preference and availability. The usual rule of diminishing returns applies.
Look for high ripple current rating and low e.s.r.
There's usually no harm (and some benefit) to be had moving up to the next capacitance rating, but keep in mind that all things being equal, e.s.r. will increase too, so it's a balancing act. In the end enough is ... enough.
Match the form factor to what you're replacing (most likely snap in 10mm, but watch for physical dimensions too)
High temp (105C) versions typically have longer life under the same conditions, but IMO it's largely academic, and they may suffer in other specifications. Smoothing 50/60Hz for home audio applications these caps will be running well within rating and should last decades without much drama (I tested some bulk caps recently out of a Hitachi HA4700, 37 years old, nothing special. Still within specification.)
Finally... price, personal preference and availability. The usual rule of diminishing returns applies.
I found (at Farnell) Epcos B41252 series with good ripple ratings, and B41505 series with good ripple and ESR ratings and longer endurance at 105C. Both higher ripple and temperature than Nichicon KG.
Do you know the mechanical details of the existing caps?
Do you know the mechanical details of the existing caps?
I will also add that I have 6ohm speakers and run the amp bridged. Myryad don't recommend less than 8ohm in that config. Will better caps make things easier on the amp?
Do you really need the higher voltage/power provided by bridge operation? The amplifier is already rated at 120W/per channel (unbearably loud in most homes) and better to use the amplifiers in standard mode for 6R loads, considering that the lowest point on the speaker impedance curve will be well below that - about 3 ohms.
Otherwise, better caps can mean longer life and/or lower impedance. Lower impedance suggests higher peak charging pulses and that can be worse for noise, depending on the PSU and supply wiring layout. Any increased stress would only be on the preceding rectifier, transformer and mains protection devices, if any.
Otherwise, better caps can mean longer life and/or lower impedance. Lower impedance suggests higher peak charging pulses and that can be worse for noise, depending on the PSU and supply wiring layout. Any increased stress would only be on the preceding rectifier, transformer and mains protection devices, if any.
Yes, these power amps sound sublime when bridged. I have 5 of them in a 7.1 system. with an additional MA360
Not really.
Just to take things back to basics. What is it you're setting out to achieve by "upgrading" the bulk capacitors?
The guy who owns the amplifier in the video must vacuum clean the house without a dust filter. That's like 90% lint inside the amplifier.
Excess power capacity shouldn't be a problem on its own. Plenty of users, likely the majority, will only be using a few watts RMS in normal use of each channel in a stereo power amplifier. 5 channels at a few watts will be quite a bit louder and adding bass content to that will make the system impressively loud. That's fine and using the amplifier with 6 ohm loads shouldn't be a problem until you hit peak bass levels of about half the amplifier's 8 ohm power rating. Bass power requirements are by far the biggest demand on an audio system and that's what to consider when you have mis-matched speakers.
The manufacturer has to cover themselves for users who assume that regardless of warnings, they can use any speaker with any amplifier and expect everything to be fine for as much as they can turn up the volume. Yes, there really are guys out there who have that much confidence 🙄
Excess power capacity shouldn't be a problem on its own. Plenty of users, likely the majority, will only be using a few watts RMS in normal use of each channel in a stereo power amplifier. 5 channels at a few watts will be quite a bit louder and adding bass content to that will make the system impressively loud. That's fine and using the amplifier with 6 ohm loads shouldn't be a problem until you hit peak bass levels of about half the amplifier's 8 ohm power rating. Bass power requirements are by far the biggest demand on an audio system and that's what to consider when you have mis-matched speakers.
The manufacturer has to cover themselves for users who assume that regardless of warnings, they can use any speaker with any amplifier and expect everything to be fine for as much as they can turn up the volume. Yes, there really are guys out there who have that much confidence 🙄
I've had these amps for years and they have been great, periodically I get them serviced and have the caps replaced as they generally last 5 years and are overdue now. rather than sending it out I will be doing it myself as I would rather have some control over the replacements. I also have subs in my system so the speakers are all bass limited to >80hz anyway which reduces strain on the amps further.
5 years only? I don't think we are actually talking about the capacitor life there, or perhaps in the past, the renewals were very poor excuses for electrolytic caps. I would expect - no, demand that they are working virtually as new for at least 15 years, as long as the temperature inside the case was well within the cap's spec of either 85 or 105C and the duty cycle was normal for the type of audio equipment.
Do you leave your system fully powered up 24/7? Some folk believe that music sounds better when their amplifier is hot and they like to keep it that way, as if the amplification was class A, even restricting air flow in cabinets, shelving and stacked on each other to keep things warm. It isn't safe practice, regardless of device safety approvals but beliefs are beliefs, no matter the evidence
Do you leave your system fully powered up 24/7? Some folk believe that music sounds better when their amplifier is hot and they like to keep it that way, as if the amplification was class A, even restricting air flow in cabinets, shelving and stacked on each other to keep things warm. It isn't safe practice, regardless of device safety approvals but beliefs are beliefs, no matter the evidence
5 years only? I don't think we are actually talking about the capacitor life there, or perhaps in the past, the renewals were very poor excuses for electrolytic caps. I would expect - no, demand that they are working virtually as new for at least 15 years, as long as the temperature inside the case was well within the cap's spec of either 85 or 105C and the duty cycle was normal for the type of audio equipment.
Do you leave your system fully powered up 24/7? Some folk believe that music sounds better when their amplifier is hot and they like to keep it that way, as if the amplification was class A, even restricting air flow in cabinets, shelving and stacked on each other to keep things warm. It isn't safe practice, regardless of device safety approvals but beliefs are beliefs, no matter the evidence
Yes you have my card marked. I'm one of those people. my system gets a lot of use, remember it's also the AV system so can be at high volumes for a few hours at a time and always left powered 24/7. never had a capacitor explode or anything but I do believe amps are happiest when left running. I don't mind the maintenance as they have lasted me over 16 years and have been great (recapping isn't expensive either) . Remember also that my Naim speakers are 6ohm so put slightly more load on each amp than is ideal (albeit they are bass limited by the processor). BTW its me in the earlier video. Those Amps hadn't been cleaned out in 8 years as they are heavy and kept on the 3rd floor.
back to the question, what do you think of the Nichicon KG?
The speakers are
1 Pair of Naim Ariva Front MA240 Mono Blocked bass lim 80hz
1 Pair Naim Ariva Rear Surround MA240 Mono blocked bass lim 80hz
1 Pair Naim NSAT Center rear MA240 Mono Blocked bass lim 80hz
1 Naim NCent Center MA360 with 1 channel off. bass lim 80hz
2 B&W Pv1 Subs
Sound corrected by Audyssey XT via Denon AVPA1HDA
As for blocking vents, I try not to but stacking is sadly the only way to Utilise the limited space I have. they are each on separate shelves though with ventilation space around each one.
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I quite like Nichicon caps generally, because of consistent quality and in my humble opinion, probably the most consistent performance over their lifetime, for a commercial grade cap. KG grade is a 'first tier' product as said earlier, so it needn't be questioned as to quality. You pay for that but you may still pay less than alleged European products which often aren't entirely manufactured there anyway. KG also comes in 3 variations, which allegedly perform differently. http://www.nichicon.co.jp/english/products/pdf/e-kg.pdf
Elna, for another example, produce a few ranges of caps with various filler fabrics and the inference that each fabric type will impart different sound qualities - a sonic smorgasbord if you like. People apparently experiment with the various grade combinations possible in their audio gear but I'm not convinced that will lead to audio nirvana. Maybe just for the time it takes until the novelty, imagined or real, wears off.
Unfortunately, I have I have no experience or data on Naim's own speaker products. I've owned a couple of Linn's speakers from before they parted company and a friend has a recent pair of Focal Arias that are used in his Naim system but even though they sound impressive, I didn't feel particularly moved to get up and dance to the PR&T thing.
Elna, for another example, produce a few ranges of caps with various filler fabrics and the inference that each fabric type will impart different sound qualities - a sonic smorgasbord if you like. People apparently experiment with the various grade combinations possible in their audio gear but I'm not convinced that will lead to audio nirvana. Maybe just for the time it takes until the novelty, imagined or real, wears off.
Unfortunately, I have I have no experience or data on Naim's own speaker products. I've owned a couple of Linn's speakers from before they parted company and a friend has a recent pair of Focal Arias that are used in his Naim system but even though they sound impressive, I didn't feel particularly moved to get up and dance to the PR&T thing.
My favourite caps whenever i cannot justify Kaisei. But surely you have mechanical constraints as well when making a choice...which kind of narrows it down a lot.
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