Replacing Capacitors Advice

Hello, I am intending to replace some capacitors on my NAD 302 integrated amplifier which is now around 12 years old. The main caps are 2x 6800uf 50v could someone suggest a replacement (and online retailer) for these which will improve sound, also I have read somewhere it is possible to double the total capacitance of these two also to increase performance. All suggestions appreciated, thanks, Ben.

 

What are the dimensions of the caps? I suspect that any 10000uF replacements would be larger diameter (and/or pitch) which probably won't fit.

You could use 4-5 2200uF parts in parallel on some bits of veroboard sat vertically.

 

It's fine to go bigger in value of caps. Sometimes up to double with electrolytics.

I bought some of the Audio ones from the maplin site to restore a Marantz and they seem ok. I suggest you have a look through the DIY suppliers thread.

The size will always be an issue (cuh!). You can always look to remount them though. i.e Run some wires fro the PCB and mount the caps on the case somewhere.

 

They are approximatley 25mm by 50mm in size. Is there anywhere to purchase siemens caps online? Sites seem awfully complicated (for comercial bulk purchase)

 

Running lengths of wire can easily add enough impedance that any benefit from increasing the size of the capacitor is lost.

Try RS (www.rswww.com) (high delivery charge) and Farnell (uk.farnell.com) (£20 minimum credit card order)

 

Thanks for the advice I have ordered two Elna Cerafine 10000uf 63v caps with the mounting clips. Will possibly need to make small mod to case to get them to fit but will see when they arrive. Thought it best to go for direct replacement, as opposed to more caps in parrallel as I don't really know how to get that right. Hope I can notice the difference though, they cost nearly as much as I paid for the amp (second hand)!

 

I've actually gone a bit further and placed an order for all the caps in the amp, using Elna cerafine with a couple of Blackgate 'n' series for the values I couldnt get in the Elnas. Found this place www.welbornelabs.com which is interesting and where I bought most of my caps from. Will let you know if this all makes a difference to the sound.

 

Remember they will need to burn in for a day or three

 

You can use larger ammounts of capacitance but you can use too much .....I tend to go 50% higher tops....just use the best you can afford ...cost is a reasonably accurate measure of performance ...if your comparing like with like on say rs or farnell.

 

The power caps alone cost £70 and the others some £50 so I have spent more on these caps than on the amp which was £90 second hand in 1996. The power caps increase in capacitance is roughly an extra 40% or so. Will try and take pics of before and after so you can rate my work!

 

The power caps arrived today, they are enormous compared to the originals, will be challenge to fit I think. lol

 

Have just been listening to my 'new' amp, although I have strapped the two enormous power caps to the top of the case and wired them through the casing to the board I think it looks cool. As for the sound, well it's absolutley wonderfull. The replacment components have given a much greater bandwidth resulting in all manor of percussion being a real part of the music now compared to the original. The timing is quite extraordinary and I am now aware of the recording that I am listening to, with distractions like pianists breathing and most surprisingly the mechanism of a church organ making me a very happy chappy indeed. It would seem to me that upgrading this amp has been the best one hundred and fifty pounds I have ever spent on Hi-Fi no doubt at all. and this is using a £27.99 dvd player as the source!

 

Nice one Ben. I'm just about to do the same to my Roksan Kandy amp.
Hope i get the same results.

 

now you need to look at the other bits ......opamps etc

sounds like it was a great move.

 

maybe you need to work on the dvd player next ben, op-amps,new clock, regulated power supplies.

 

The dvd player is only a stop gap measure as I am intending on purchasing a turntable as my source. Unfortunately a £1000 car repair bill has put the turntable back a few months. What is it you intend doing with the the Kandy Andy?

 

I'll be doing cap swaps all round Ben. The amp already has a decent alps volume pot and looks well built, although i may look at uprating the rectifier bridge soon.
Thinking of using elna or panasonic fc for the electrolytics and psu caps. The psu are already 8200uf80v so i thought i'd raise them to 10000uf and see what benefits i get.
2x10000uf's gonna cost though!
The amp's the only part of the system i haven't tinkered with yet so i thought it'd be rude not to
The system already sounds great by the way (to my ears anyway)

 

The power caps I used were Elna Cerafine 10000uf 63v (with the originals being Wendall 6800uf 50v) and this has made a huge improvement in bass and dynamics. It was roughly a 40% increase in capacitance and cost roughly £32 each from Hi-Fi collective (I used two). The equivalant Black Gates were nearly £200 each! I have 4 Black Gates in my amp now but only bought them as could not get correct values in Elna Cerafine.

 

Yep, those black gates cost an arm and a leg all right! apparently they can take an age to burn in properly so you may still have some improvements to come.
Glad it worked out well.
My mod probably won't be as effective as the caps i'm replacing are newer, although should be worthwhile all the same.

Quick question...
The Psu caps-from what i've seen in pictures, these have metal pins rather than wire legs.
Do these go through the pcb to a trace underneath or is it more complicated than that?

 

It depends on the type but mine have large flat lugs with a hole in so you can thread the wire through and round then solder the joint. I think you will find that the size of the upgraded replacements will make fitting directly to the pcb unadvisable. If you buy ones with pins try and find the diameter of these pins as you do not want to be making the hole in the pcb any bigger. It really is a case of sizing it up. See if you can find some 12000uf caps for a greater improvement.