#96 - Servicing NAD C350 stereo integrated amplifier

[@chrisdado]

For anyone looking to replace the main power supply filter capacitors on this amp I can confirm the following ones from mouser will fit (just): United Chemi-Con 22000uF 63 Volt (SMH Series), MFG Part No: ESMH630VSN223MA65S I used these in a recap and they tested well and a have good ripple tolerance, just over six dollars each.

[@DiegoooTech]

I love amplifiers and I always learn something when you put your hands on it. I also really love your work in this channel. Great videos. Even when things look simple you explain every step and something interesting emerge. Favourite channel.

[@yngvenystrand167]

A DC voltage across the pot due to a leaky cap can also cause scratching noises when the pot is turned.

[@robertw1871]

Don’t be afraid they are fake, they are... being half the rated value tells you for sure they aren’t from Nippon...

[@robertw1871]

@Melvin Ezekiel The scriptkiddy gets haxord.

[@ВладимирПутин-е7м]

I have this amp. I love it. It's run flawlessly for years until 'something happened to it'... and I had to have it repaired. Cost me a $120 to get repaired. If I'd seen your videos I probably could have done it for nothing.

[@audioteckltd5845]

I got mine for $90 USA and so far so good, still running strong for 10 years

[@hadraai]

Thanks for the very informative video. I have recapped the same amp and also searched everywhere for the 2 buffer caps. I seems that even NAD service-centers replaced them with 15000uF 63V 105DG's because of the limited space. 30KuF total is easily enough I think for this amp. I bought 2x EKMH630VSN153MA63T at Mouser. Please make sure to order the VSN version, I had made a mistake at first and ordered the VND version with the wrong pin-spacing and 2 extra pseudo pins. Good luck man and thanks again.

[@feedback-loop]

How do you know about NAD service centers replacing with 15000uF?

[@hadraai]

@@feedback-loop Because I found a post by a repairman who said: "The problem you will have is that the original caps are only 35mm in diameter with no room for anything wider. IIRC when NAD supplied replacements they lowered the capacitance, also make sure the ones you fit are rated at 105 degrees, the originals were 85 degrees and I had to change quite a few over the years"

[@hadraai]

@@feedback-loop And also because a much bigger (more power and headroom) amp in the range the NAD 317 has 28.200uF total of buffering. For this 'small" C350 30.000uF had to be more than fine.

[@andymouse]

Very interesting, buying capacitors is tricky, nice explanation...cheers.

[@Alpejohn]

Great video! I also have this amp, i bought it new in around the same time as you (2001 ish). Mine still works great, but as you mention, i have problem with channels, the sound is lounder on the left channel. If i turn up the volum on the source (my pc) i can get the sound to come back for a little while. The volume knob is working fine, i think the balanse knob is my problem. I think i will try to clean all the pots just to be sure. Not sure if i will try to change the caps, i have to look into it tho, cause it is tempting. I will probably open and clean it and have a look and go from there.

[@gordthor5351]

The reason it doesn't have a switch for 4 or 8 ohms is because it doesn't need it. The older version obviously couldn't (properly) handle 4 ohms loads, so NAD added a current limiting switch (4 ohm setting) which actually produces less power on a bench test than the 8 ohm setting. You have to be smart about it if you use 4 ohm speakers on the 8 ohm setting so you don't push the amp too hard and blow transistors. However, it should perform better with dynamics on the 8 ohm setting.

[@SidneyCritic]

I was going to skip the vid when it was only a scratchy pot, but it got good with the cap repair.

[@TrevorsBench]

I've got two of these on my bench at the moment and all the capacitors are garbage. NAD does make nice sounding gear but their design quality is junk. Cheap components and very poor heat dissipation management, plastic front panel to name a few. I noticed that resistor R227 on your amp. is the under rated type. There was a service bulletin about replacing this resistor with a 560 ohm 2W fusible. Also, there was another service bulletin for caps C511, C512 and C513 that need to be changed from ceramic disc to film Thanks for the awesome repair video, Cheers

[@RotxuF]

I've seen your repair vids. Nice jobs. I just repaired a 315 model and again essentially all the caps that are smaller then 220uf are completely shot !

[@DanielMelendrezPhD]

I would suggest you to make your own bank of capacitors, I understand that there are some space constraints however, it might be your best option due to the scarcity of high-capacitance ones on the market at the moment

[@twobob]

Sweet, I have a Quad 303, and a Leak Stereo 30 Plus to restore, appreciate the tips.

[@jeffm2787]

Often the physically large caps will last a very long time. As we all know heat is what kills most of the smaller ones. In an amp it's hard to find anywhere that's really cool.

[@stewartholmes7927]

I'd of rearranged the vertical circuit board to where the original main filter caps are and put a capacitor bank in it's place. Possibly the standby transformer would be better (heat) yet I'm guessing it's wires aren't long enough

[@dirtydon8661]

Enjoyed your service video. Very technical.

[@ElectoneGuy]

NAD kept/keeps costs down by manufacturing in China. The problem is a lot of the caps they used were no-name junk like "Giant" brand.

[@thethirdman225]

At least they are made to NAD specs.

[@ElectoneGuy]

Never buy filter caps off of Ebay or Ali Express. They are knockoffs and although some will measure well, they will not last and even worse, may blow up during use. Ask me how I know...

[@beatingbytes1692]

For me, the primary filtercaps are fine. Even the rattling sounds more like a loose plastic disc on the top of the cap, then a broken or defect cap. Normaly they wont fail, even after all the years of usage.

[@Irilia_neko]

You know the rattling it's because it's a small capacitor inside ^^

[@synaesthesia2010]

If you're doing a repair video, you should show a teardown too so those of us with the same amp or with one in the same range will have an idea of how they come apart

[@CarlosAvellanet]

Have you ever used DeOxit5? I swear by that stuff.

[@BaconbuttywithCheese]

Very nice bit of maintenance. How do you find the TongHui? I am just about to purchase an LCR meter and am wondering if a Hantek at 1/3 of the price will be just as good.

[@feedback-loop]

In my view the TongHui is quite good. 0.25% basic accuracy. The model I have supports up to 100KHz. It was about $300 some years ago. The input connectors are a bit flimsy, so I had to take it apart a couple of times to bend the contacts slightly towards each other, so that they would make better contacts with the plug. I have never seen Hantek.

[@BaconbuttywithCheese]

@@feedback-loop thanks for your feedback and videos.

[@Todestelzer]

Andrew Pratt I will buy a DER EE DE-5000 this year. Best bang for buck. Only 100€ with accessories.

[@BaconbuttywithCheese]

@@Todestelzer That looks like a good recommendation, thanks!

[@PeterMilanovski]

@@feedback-loop I was surprised that it could read the larger capacity of those capacitors! I have a few different capacitor testers but they can't read the larger capacitors! That's a real problem because I have a couple of those cheap eBay Chinese capacitors that I purchased some time ago and I was planning to use on a project but now I'm not so sure that I'm going to use them! I might end up putting them in a test circuit and let them charge and discharge to see how they will perform over time. I don't mind if their capacity is lower than rated, as long as they don't fail into a short circuit. It's also possible to make up your own capacitor bank using a perf board and multiple smaller capacitors, the ESR will be super small and it's easier to get better brands in the smaller values...

[@artur7587]

Do you have schematics and/or service manual for NAD C350? Searching over the web but found nothing :/

[@feedback-loop]

www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Nad-C-350-Service-Manual.pdf

[@M0XFXUK]

Out of interest, what is the DC voltage of the power supply i.e. what voltage does the power supply put across the main smoothing capacitors?

[@feedback-loop]

50V

[@M0XFXUK]

@@feedback-loop I was hoping that the voltage was slightly lower than 50V, so you do need 63V as a minimum. I have looked on the RS Components website in the UK and the best I can find at 63V is dimensions of 40x80mm manufactured by Kemet which I think maybe too tall for your application. I am based in the UK but work mainly in Denmark, I have become friends with a gentleman in Viborg who runs a business repairing and restoring new and vintage, high-end HIFI equipment. I will ask him for some advice for you in the hope that he may have a solution to your problem. I really enjoy the videos, keep up the good work. Best regards John from the UK and Denmark.

[@feedback-loop]

@@M0XFXUK I have seen such caps on Digikey or Mouser or both. 80 mm caps won't fit. I will keep looking. This is not urgent. The original ones are not failing yet. Thanks.

[@M0XFXUK]

@@feedback-loop Arrow electronics (arrow.com) have 22000UF 63V 40X60mm in stock manufactured by Kemet part number: A533HK223M063G.

[@feedback-loop]

@@M0XFXUK I am afraid that 40 mm diameter is too large. The original ones are about 35 mm and almost touching each other.

[@tuanto9618]

The power led is green but The input source led not light? Help me,bro

[@markthackray3185]

Thankyou for this video! I have the c352 and have recapped it as the old ones were totally shot. Huge difference in performance. Very happy. I haven't done the large caps which are identical to the ones in your video. Hard to find them so ordered two 'jccon' Chinese ones which are on a rowing boat making there way across the ocean as we speak!! So after watching this there's no way I will use them. Why can't anyone make genuine ones? And why did nad put such crap into such a capable amp?! Tempted to make an external power supply with banks of caps. But I would rather stick to original setup. Awesome video - 👍👍

[@feedback-loop]

Looks like these should do, but I did not try myself yet: www.mouser.com/ProductDetail/United-Chemi-Con/ESMH630VSN223MA65S

[@ljubomirculibrk4097]

Its ABS plastics, fatigue cracking under constant load if normal after that time span. Drop of superglue behind, after drying aply dental repair cold acryl two part resin (powder and liquid). Budget repair is cotton and superglue, old t-shit piece or a raw fibers, poor mans composite.

[@benw2751]

thank you

[@nicwilson89]

Superglue and things like baking powder can sometimes work rather well, too

[@mangist]

Cut that 22000uF cap from China open, you'll probably find a smaller electrolytic 12k uF inside lol

[@donsutherland5706]

I enjoyed the video. Thanks!

[@paulpaulzadeh6172]

Those capacitor on eBay from china are not original ( fake) , they put plastic sleeve the same as original and sell it as original

[@Johnathan_Waters]

HOW is it possible that the 22,000mF caps tested within spec, even though there is literally something loose and knocking around inside them??

[@Irilia_neko]

Because they are real fake, it's the capacitor inside that knocking xD

[@Johnathan_Waters]

@@Irilia_neko Ahhhh I see! That's incredible! I had the same problem with the filter caps that came FACTORY inside my Harman Kardon AVS235!!

[@Irilia_neko]

@@Johnathan_Waters because people think à Large capacitor it's better, open the blue can and you will find the real value normally, otherwise mesure the capacitor wen it's working it's clearly not a high voltage, just don't touch the PCB when measuring the voltage by principle.

[@Johnathan_Waters]

@@Irilia_neko Thank you for this info!

[@Irilia_neko]

@@Johnathan_Waters my pleasure if that can help ^^

[@gbowne1]

I tend to snag the stuff bigger than 10000uf on eBay.

[@MrRobbyvent]

no final sound test?!

[@feedback-loop]

Well, it was not really a repair, it worked before, but you are right, I should have shown some test at the end.

[@SDS-1]

👍👍👍👍

[@christian56311]

Can you please feature my Tektronix 465 on your channel? It just quit working 2 days ago.

[@victimovtalent6036]

There are fake branded cheap capacitors around the world..guess where they are from?

[@ЮрийБаянов-г7ж]

ОТЛИЧНЫЙ УСИЛОК

[@sailing_raptor]

Nad is a word in itself, the letters do not form initials.

[@feedback-loop]

Wikipedia says: "NAD is an abbreviation for New Acoustic Dimension"

[@sailing_raptor]

@@feedback-loop be that as it may, as an acronym, it is in itself a word.

[@feedback-loop]

You are, probably, right. Someone, who lived next to the original office in London, also commented that it should be pronounced as a word. I have to remember.

[@SamFirthDesigner]

The company name is "Nad" but it does form an abbreviation.

[@sailing_raptor]

@@SamFirthDesigner it isn't an abbreviation, it is an acronym.

[@bobbarcus8310]

I would not waste my time putting in cheap capacitors from China I have but the older Capacitors from China before and open them up and there was a chance it capacitor inside of a cardboard container stay away from Chinese stuff it’s all cheap crap

[@eknaap8800]

Please use another microphone; this one sounds too muffled... 😢 BTW, there is no such thing as 'supper contact cleaner. 😂

[@ДмитрийСумароков-з2в]

с ебея привезли неликвидные конденсаторы к сожалению

[@TheGmr140]

just buy a new one, NAD have been junk for years. switch to Marantz, the high end

[@TestEquipmentAnonymous]

"just buy a new one" is an invalid command on this channel 😁

[@TheGmr140]

@@TestEquipmentAnonymous just trying to mix it up and have a laugh.

[@TestEquipmentAnonymous]

@@TheGmr140 Hehe, yep.

[@PeterMilanovski]

Speaking of new, has anyone seen the new Yamaha amplifiers? They still have that old school style look on the outside and they actually look very good on the inside too! I could be mistaken for saying this but it's almost like buying a new old stock amplifier! Even Technics has released new Amplifiers that appear to be like their older stuff! Who knows, maybe a cassette deck is in the pipeline? I really hope so! With the world population growth, and vintage equipment slowly disappearing, there's just not enough of it to go around for everyone so I think that it's great that the old school masters of hifi building from Japan are back at it. Now all that we need is to get it made in it's rightful place, Japan.