Hi all, I have a naim AV2 I use for AV and realising its now 20 years old I decided to treat it to a recap of the Tantalum caps as I understand these are the units needed replacement at the recommended service interval.
I have my naim power and pre-amps serviced 'normally' and quite capable of doing the work, but for some reason wanted to keep the main amps serviced with correct parts etc. Anyway my question is I have 34 tantalum caps to be replaced all 10uf 35V and I have the correct replacements but after taking 6 out, I have realised they are all very well marched (more so than my 5% replacements) and all measure 11.2uf and all measure the same or close ESR to the new units I have bought. So given I am about to spend many hours carefully removing and adding 10uf (that mostly measure 9.9uf) with similar ESR am I just about to burn £100 and a day or so of fiddling to achieve nothing ?
Any advice on the Tants and perhaps some take more wear than others I did pull one off near the regs as this is feeding the +- 15v Opamp rails and this measures, 11.2uf and bang on for ESR as well. Are naim just avoiding premature failure with the 10 year replacement, I had understood the ESR normally raises before any failure ?
I have my naim power and pre-amps serviced 'normally' and quite capable of doing the work, but for some reason wanted to keep the main amps serviced with correct parts etc. Anyway my question is I have 34 tantalum caps to be replaced all 10uf 35V and I have the correct replacements but after taking 6 out, I have realised they are all very well marched (more so than my 5% replacements) and all measure 11.2uf and all measure the same or close ESR to the new units I have bought. So given I am about to spend many hours carefully removing and adding 10uf (that mostly measure 9.9uf) with similar ESR am I just about to burn £100 and a day or so of fiddling to achieve nothing ?
Any advice on the Tants and perhaps some take more wear than others I did pull one off near the regs as this is feeding the +- 15v Opamp rails and this measures, 11.2uf and bang on for ESR as well. Are naim just avoiding premature failure with the 10 year replacement, I had understood the ESR normally raises before any failure ?
Tantalums aren't supposed to age like aluminium electrolytics.
Some older one's might have less safety margin from failure, which might be a reason for replacement.
If all of them are 10µF that suggests they are all decoupling or blocking caps, for which exact value isn't at all critical.
The modern rule for reliability in solid tant's is to derate voltage by 50%, so for a 20V circuit 35V cap isn't enough, change to 50V.
https://en.wikipedia.org/wiki/Tantalum_capacitor
Some older one's might have less safety margin from failure, which might be a reason for replacement.
If all of them are 10µF that suggests they are all decoupling or blocking caps, for which exact value isn't at all critical.
The modern rule for reliability in solid tant's is to derate voltage by 50%, so for a 20V circuit 35V cap isn't enough, change to 50V.
https://en.wikipedia.org/wiki/Tantalum_capacitor
Mark, thanks
The Voltages are mostly sub 15V, Although some 20V DC from the power supply to the regs but I dont think the tants are pre reg at that point. The 50V tants move from £3 to £8 each so 35 of them would add up, I will put back together and see which ones are over 15V and add it to the list of later upgrades I think
The Voltages are mostly sub 15V, Although some 20V DC from the power supply to the regs but I dont think the tants are pre reg at that point. The 50V tants move from £3 to £8 each so 35 of them would add up, I will put back together and see which ones are over 15V and add it to the list of later upgrades I think