Hi, I've had my NAD C325BBB around ten years. Pressed front panel ON/OFF last week, amber light doesn't go green. I've downloaded the service manual. Found out there is no +37VDC at CB53 (the power out 7-pin connector on the power board). However, on taking out the power board, all the solder on the +37V pin has melted, giving no volts to the main board. So I'm gathering there was a fair bit of current being drawn by something on the main board. I'm unable to find any short-circuit on the main board at the +37V in points, ie jcn R41/R45 and at R427. Has anyone had this sort of fault on these NADs?? Also reading another post of a NAD C320 he talks about notorious capacitors!! Can anyone enlighten me about them, please?? Many thanks for any help.
The brand of electrolytic caps used in my C325BEE were JH (Jianghai) and JAMICON....both low tier brands.
Many were physically ruptured, many failed high ESR specs. The pre-driver riser PCB uses SMD caps, these were failed too.
The power PCB was a complete mess with e-cap rupture corrosion damaging the ribbon cable connector and the DB104 diode bridge.
So yea, NAD are good audio designs it's just the physical implementation of the designs is sub-par.
End result, repaired with proper components my amp works very well.
Many were physically ruptured, many failed high ESR specs. The pre-driver riser PCB uses SMD caps, these were failed too.
The power PCB was a complete mess with e-cap rupture corrosion damaging the ribbon cable connector and the DB104 diode bridge.
So yea, NAD are good audio designs it's just the physical implementation of the designs is sub-par.
End result, repaired with proper components my amp works very well.
I have used the NAD C320 for many years, I assume it is similiar to the 325. The 320 has a lot of discretes. The driver transistors are on 4 heatsinks with 3 transistors screwed together on the same heatsink. It still works but I am afraid that some failure will ruin my speakers. So I am replacing the C320 with hybrid C338.
The NADs are designed in Pickering, ON, Canada but assembled in China. IMO, it would be better for quality control to do design and production in the same facility.
The NADs are designed in Pickering, ON, Canada but assembled in China. IMO, it would be better for quality control to do design and production in the same facility.
Right, many thanks for that. There's an RS place down the road from me (South Wales, UK), they do Panasonic capacitors so I think I'll replace all the electrolytics while the amp's in bits, and my LPs and CDs of Arnold Schoenberg and Gregorian Chant (only joking) will just have to sit patiently... 🙂 I suppose after ten years all those caps could do with replacing?!?!
Well I don't like to just generally replace all the electrolytic caps...but in my case I did. As I said the majority of the electrolytics were failing.
For the riser boards, I used polymer SMD instead of the standard electrolytic SMD. The polymer from what I read is more stable and those riser boards generate a lot of heat.
Again I don't like to generalize but NAD seem to use the cheapest capacitors and PCBs. I have a 310, 3155, 314, 7125 and this 325BEE; in each case low tier branded caps, many failed ESR and physical leakage along with bad traces and/or fractured boards.
But if you research NAD this was their SOP; design state-of-the-art audio equipment but contract the manufacturing to inexpensive factories. This made the products more affordable than the competition. And it's a consumer item, so 10 years is "good enough" using this mindset.
Those NAD models I own I purchased DOA. I think only one amp had a failed output transistor. The others were failed caps or a PCB problem causing channel outage or always in protect mode.
Anyway, enjoy the restoration adventure; the end result is a fine sounding amp.
Thanks for all that, JH. I suppose these cheap capacitors just go leaky rather than dead short, do they, apart from visibly leaking? I used to work in avionic workshops where all the components were military grade and very rarely failed.
yes, electrical leaky to very high ESR. Some do show visible signs of failure, but high ESR is typically the fail point. All of these statements are my opinion so
as the saying goes "your milage may vary".
If possible I replace with 105C ratings (automotive spec?) and the next higher voltage spec.
That is the other item, many times there's not much headroom for the working voltage component spec versus the measured circuit voltage.
as the saying goes "your milage may vary".
If possible I replace with 105C ratings (automotive spec?) and the next higher voltage spec.
That is the other item, many times there's not much headroom for the working voltage component spec versus the measured circuit voltage.
Thanks again, JH. One more question if I may, will my remote for the 325 operate a 320? There's a good 320 on Ebay which I'm thinking of getting. Cheers.
Not sure if the remote works for both.
I do not have one, I just use an app from the android phone to control.