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old capacitors (in their day) vs new

i feel like if we all put our heads together we could assemble a go-to thread of information for those looking to replace filter caps/signal path caps. wih how many caps are out there and available to people, we could save a lot of people time and money by outline the best caps for certain jobs. i know it sounds time consuming but sticky threads of valuable information are how i learned a lot of the things i do mechanically. forums alone took me from jetting carburetors on small engines to rebuilding engines to cummins ford swaps, wiring, etc.. and that knowledge gave me the confidence to work on old stereo receivers and amplifiers i have. thanks to everything thats been leading up to this moment in time and knowledge, ill be able to fix a rockford fosgate car amplifier with bad power supply caps that i got 2 years ago unsure of how to fix it.

it helped me fix my 3125, my sta-78, soon to be other things.

people take the internet and its ability to teach for granted, but ive been addicted to learning from forums since like 2004
 
It makes sense, but every time I recommend a particular part number it seems like they immediately discontinue it.
 
these nichicons are very accurate and have incredible sonic resonance to them, but the bass just doesnt thump like it should. its there, the accuracy of the pluck is there but the thunk (the amount i feel should be) is not
 
maybe just like a thread for 100-130 wpc receivers we could make a thread where people can share what caps they have used for certain applications and their experiences good and bad
 
even finding out the specs on caps that have been discontinued would be a good reference for people that may need to replace a discontinued cap
 
Probably drifting a bit OT, but one should remember that the PS caps ability to deliver current shouldn't have any significant affect on the amps output until the voltage sags so far that the amp actually clips. It's the amplifier circuit (and its feedback) that determines what the output looks like and if the output doesn't look like the input, even when the supply varies, I'd accuse the amplifier of a significant design flaw. Unless you use tubes, then all bets are off, because the gain and amount of feedback are less.
 
ConradH said:
Probably drifting a bit OT, but one should remember that the PS caps ability to deliver current shouldn't have any significant affect on the amps output until the voltage sags so far that the amp actually clips. It's the amplifier circuit (and its feedback) that determines what the output looks like and if the output doesn't look like the input, even when the supply varies, I'd accuse the amplifier of a significant design flaw. Unless you use tubes, then all bets are off, because the gain and amount of feedback are less.
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well worst case scenario then it sounds exactly the same but with capacitors that will last longer and ill have 4 kg gold tunes for other stuff whereas the big cornells that are on the way wont fit in anything but this 3125
 
Karl vd Berg said:
... and what about using 2 "ordinary" caps of, say, 5,600uF (total of 11,200uF) instead of a single expensive 10,000uF?
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each channel is using two 80v 6800uf caps, im replacing each with 100v 10000uf for a total of 40000uf filter capacitance instead of 27,200uf

i guess i could rig it up to use 4 caps per channel, but i dont think i want to. thats something to keep in mind though. sorry for not really understanding at first
 
yotems said:
each channel is using two 80v 6800uf caps, im replacing each with 100v 10000uf for a total of 40000uf filter capacitance instead of 27,200uf

i guess i could rig it up to use 4 caps per channel, but i dont think i want to. thats something to keep in mind though. sorry for not really understanding at first
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Hi,

Yes, I meant using multiple caps in parallel instead of a single for higher ripple current ratings and overall performance. But the Cornell D. caps are good enough to avoid the hassle of multiple caps in parallel. Which size (diameter and height) are the original main filter caps?

Are you also replacing the rectifiers for the new 40,000uF total capacitance?
 
Blue Shadow said:
I mentioned this in another thread. The older caps have different specs than newer caps. I can't say for sure what the specs were in the old caps but the new caps have published specs. When you get to the larger caps, ±20% is common and with modern 6-sigma manufacturing techniques, the cap can be built at the low end of the range, say 10-15% below the value stamped on the cap. Back in the day, statistical process control was just getting underway with W. Edwards Deming's work at Sony in the 50s. I'm sure that the improvements were spread throughout Japan but how long it took to get to the capacitor manufacturers, I don't know so a new cap back then, maybe rated -10%/+70% may well have been built at the +20% level to achieve consistent 'on-grade' production. I'm not saying this is the way they were made, just throwing it into the discussion on caps.

This means that 10,000 cap would be measured at 8500-9000 for a new cap and measured at 12000 for an old cap when new. That is a big enough difference to be a possible cause of the lack of performance on the new caps. We may be putting in caps that were below what was used back then and calling it good.
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That is why on Vintage gear I always try to go up a value or two depending on the circuit its in. For PS i alway go up in uf and or Voltage..

But one thing to try to lower is the existing ripple current before it gets to the caps, not easy to do...then all this ripple current talk wouldn't matter ;)
 
Hyperion said:
You know of course that the heart of a good amplifier (particularly SS but also Valve) is the transformer, increasing filter capacitance only helps a little and up to a point.
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but going down in filter capacitance certainly cant help. not saying i did but its possible that i may have. ive read that going up in capacitance is best in small doses
Karl vd Berg said:
Hi,

Yes, I meant using multiple caps in parallel instead of a single for higher ripple current ratings and overall performance. But the Cornell D. caps are good enough to avoid the hassle of multiple caps in parallel. Which size (diameter and height) are the original main filter caps?

Are you also replacing the rectifiers for the new 40,000uF total capacitance?
Click to expand...

i guess im going to leave the rectifiers alone for now, didnt intend on changing anything but the caps. ive seen people go with 100v 10000uf caps in these 3125's before and didnt hear of any ill effects (knock on wood). i figured if this nec 910 rated at 110 wpc 8 ohms .006 THD 10hz-40khz has 4 10000uf 71v elna's then the 3125 should be ok with 40000uf total capacitance.

it uses the output transistors the pioneer sx-1980 used and a sansui 9090 db sized transformer
 
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