Power supply help please

BIA

Member
2011-01-08 12:14 am
Hi can someone help me , i just replaced the power capacitors in my Linn LK-85 power amp , i replaced the 10,000uf 63v with 15,000uf 63v .
Should i also replace the next set of capacitors which are 100uf 63v .

Because i seem to have lost some sound quality in the high frequencies , such as the symblos there washed out not bright .

Has anyone had experience with going up from 10,000uf to 15,000uf and changes they had to make to smooth the new capacitors .

Help appreciated

BIA
 
Has the power supply voltage changed from before? Do you have a schematic to work from? Was there something wrong with the other power supply caps? It is unlikely that this change could effect the sound and some caution should be used when substituting power supply values that are 50% more than the design values. It works so you diden't break it, but bigger value caps require higher charging current so I hope it keeps working.
 
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BIA

Member
2011-01-08 12:14 am
The power supply voltage is the same i dont have the schematic for the LK-85 , the old caps i suspected of having blown as they looked blown , the new old caps were 4A ripple current and the new caps have a 7A ripple , im just letting them run in . im getting the same dc value at the out put 2mV DC . but there is a definite change in sound i may go back to 10,000uf with 4A ripple current its the only thing i can do
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Fitting larger caps than originally specified is a common trend in the belief that bigger is somehow better. However in this case I suspect 10K to 15K isn't going to make much difference in practice.

Sometimes when swapping parts, your expectations are sky high and the result can be a bit of an anti-climax. Personally, I suspect the reality is that the sound is just as it was before and if you relax and listen, perhaps over a few days, you will find the same.

Just my thoughts :)
 
The new caps may have a lower ESR, which could make the charging pulses slightly more peaky thus increasing magnetic induction. On the other hand, lower ESR would also make the DC output have a smaller spike during the charging interval so you could get less PSU IM - this ought to be a good thing but any subtle change in sound can be perceived as the opposite of what it actually is. Only gross changes for better/worse can be reliably assumed to sound better/worse.