capacitor advice

[tomst]

Hi I need some advice on capacitors.
The amp is an Arcam Alpha 5 and some of the electrolytic caps are ready to be replaced so i thought it would be a good time to upgrade them.
I have attached the images of the PSU, Pre amp and Power amp and have circled all the electrolytic caps.
My thoughts are that fitting a better capacitor in C1, C10 and possibly a MKP type capacitor in C9 would be better.
The PSU caps are Jamicon 50V
100µF/10µF and 22µf are Rubycon CE W 25V, 50V and 60V respectively
and the 100µF are Samhwa (S6) (M)9405 50V
i will also be renewing the Q15 mute transistor and possibly Q1/Q2 power amp transisotor

Thanks
Tom

 

[jaycee]

MKP capacitors are much larger, which will give you mounting issues. I personally wouldn't bother. However, if you can get 10uF Wima MKS2 series capacitors, these will be improvements for coupling capacitors like C1/C101, C405/C505, C606/C706. For C1/C9 a 100uf MKP would be huge - stick to electrolytic.

Simply use good quality electrolytic to replace - Rubycon, Nichicon, Nippon Chemicon, Panasonic are all good brands. I personally like Panasonic as they are easily available from CPC.

Replacing the muting FETs is probably a good idea as the old ones can be flaky. I wouldn't bother replacing the output MOSFETs unless they are damaged - incidentally the SMF045 are no longer made, and Arcam adapted the design to IRF540N

 

[tomst]

Thanks for your reply I'm new to this and I'm still learning. I understand how the components work and how components make a difference but knowing/selecting what components to use and where i still need to learn. also it takes me a while to work out how the whole circuit works.
One of the MOSFETs is on its way. looking at CPC/Farnell they have a few different versions of the IRF540N the only one Readily available in the uk is IRF540NPBF. I guess this is correct? and i suppose it's just a drop in part?
For the electrolytic caps i don't suppose the voltage rating matters as long as its not lower than what the originals are and the pin spacing is suitable/adaptable. regarding the panasonic electrolytics there are various versions ECA,ECO,EET,EEU which are best? or are they all the same but take the one with the lowest ESR if shown? For c10/110 would an MKP be better as it is the fist thing in the signal path If space and size weren't an issue? Farnell only has MKS4 in 10 µF which i guess are the same but with different pin spacing? I can't really find any thing on the rubycon CE W but i don't think they were audio grade caps so i guess any modern cap will be an improvement on these anyway

Thanks
Tom

 

[homemodder]

Tom, for excellent audio supply caps look here BHC - AudioCap Limited.
Made in the UK.

 

[indianajo]

Having had to replace e-caps several times in some equipment over the years, I buy the ones with the highest hours life rating. I try to buy nothing rated under 3000 hours. I haven't downloaded all those series but I have bought Panasonic EEU's with lives quoted over 8000 hours. ECA appears to be a 1000 to 2000 hour rated cap.ECO appears to be slightly better. One odd thing about Panasonic caps is that the datasheets I receive by clicking the link on the supplier selector chart do not have the letter combination that is listed on the selector table. I haven't been watching ESR and haven't caused trouble in any of the over 150 overage e-caps caps I've replaced in the last two years. The brand names are nice but all mentioned sell "popularly priced" caps and long life ones. I won't say initial quality of any brand mentioned is bad but I run the hifi 1300 hours a year and the PC 5400 hours a year. The six year old PC mainboard had two caps fail two weeks ago, taking me off line where I couldn't select caps by selector table.

 

[homemodder]

Agree, here, Ive had to replace most caps in my 3d video card, after 2 years they started literally exploding one by one, they make a hell of a bang when they go, gunshot like.

My pc doesnt get switched off ever year out, I find this actually prolongs the caps life.

 

[jaycee]

PC problems are due to squeezing price margins, low ESR and good quality is especially important in high speed, high power DC-DC conversion used everywhere in PC's, and yet a good deal of stuff has cheap Chinese junk instead of quality parts.

 

[tomst]

Ok going to replace the electrolytic caps for the ones in the signal path i guess the Panasonic FC/FM or Rubycon ZL are a good option. But what about the caps in the decouple the power supply rails to earth in the power amp stage. Will FC/FM/ZL be good for this or is a capacitor with a higher impedance better?
On replacing the MOSFETs i guess it's a drop in replacement and reset the quasient current.
Thanks
Tom