Hey guys I have C370 that I recently replaced all the electrolytics on. It's been biased etc. and working and sounding very well.
One thing that really bugs me is the various adjustment trim pots. The DC offset pots have enough travel that I can accurately (enough) set them. The bias pots are way more fiddly and basically to get bias within range requires such small pot movement that it's close to impossible. The ICS pot is just as bad. I feel like if I look at them wrong, they'll drift out of spec. Given that this is how NAD shipped them out of the factory I'm sure it's fine but due to a high level of annoyance I'm going to replace them all with multi turn versions so they're less sensitive.
My question is, is there something in the amp that I could swap for a better version for audio improvement? Better resistors in specific places? I'm not an engineer, just a builder so any help would be appreciated.
Cheers
One thing that really bugs me is the various adjustment trim pots. The DC offset pots have enough travel that I can accurately (enough) set them. The bias pots are way more fiddly and basically to get bias within range requires such small pot movement that it's close to impossible. The ICS pot is just as bad. I feel like if I look at them wrong, they'll drift out of spec. Given that this is how NAD shipped them out of the factory I'm sure it's fine but due to a high level of annoyance I'm going to replace them all with multi turn versions so they're less sensitive.
My question is, is there something in the amp that I could swap for a better version for audio improvement? Better resistors in specific places? I'm not an engineer, just a builder so any help would be appreciated.
Cheers
Is this like the NAD C320 which is all discrete parts. The schematic is formidable. I repaired it once when a shorted capacitor took out the 18v supply. It worked for several years but now the audio volume fluctuates intermittently. I believe this is hard too fix and not worth the effort.
So for the C370 you need service manuals, schematics, and tools. Designs with bias pots are more likely to degrade into distortion.
Recent NAD designs are computerized amps like the 3045.
https://www.diyaudio.com/community/threads/nad-d-3045-overheating-allegedly.379438/#post-7069133
So for the C370 you need service manuals, schematics, and tools. Designs with bias pots are more likely to degrade into distortion.
Recent NAD designs are computerized amps like the 3045.
https://www.diyaudio.com/community/threads/nad-d-3045-overheating-allegedly.379438/#post-7069133
NAD was plagued with bad caps for some time and their current FDA devices don't shine bright either with regards to longevity. The recapping debate can be skipped with the C series by NAD, just replace ALL the electrolytic caps.
Not much else beyond internal signal wires and opamps. I'm a huge advocate for internal wiring upgrades where possible.
Yup, as I noted, I've already done that. I'm just curious if there is something else that can be replaced for a relatively easy improvement.
There are none of those on this model. Well, ok, there is some internal wiring but unless NAD screwed up the gauges required (doubt it) I'm not interested in audiophile magical wires. Maybe people can hear a difference in wire material but I sure can't. I guess mainly I'm wondering if upgrading any resistors to low tolerance metal film versions would be of benefit.
If the power amps are on the separate boards, maybe you can replace them with some off-the_shelf or DIY modules.
The power amp has a single bias pot affecting 9 transistors. There are 2 triplets of transistors in parallel. Each has it's own emitter resistor. All these transistors need to be matched to prevent distortion. It looks to me like an unreliable design.
Man, I sure am for what they've given me, but you're right, C370 doesn't have many - only signal, which doesn't carry as much impact as internal speaker wire. Not going to even try to convince you, but respectfully I don't think you've tried - it's done great things for me..
Sorry didn't mean to come off as snide or whatever. I'm not going to tell people what they can or can not hear. Just meant they're not for me. And yes I've tried some. And various hearing tests I've done point to above average hearing. However, I'm still open minded that others may hear something I don't. The ears and brain are too complex for me to pass judgement.
What kinda wire did you use? What’s the main differences you noticed in you mad? I have the same one 90’s 2 prong plug no ground in the plug.
Well, couple of things gents - To Jedi, no apology necessary, I was once a cable non-believer and understand, with experimentation in what you are looking to achieve, I would consider internal wire since there is not much else with the NAD you have beyond caps - just a point.
@Jeffrey - I've used lots, most recently Mundorf SilverGold. Expensive, but when used internally one doesn't need much. Most recently I replaced the internal speaker wire from the board to posts on a Bryston 4B-ST, and achieved an amazing result. Better response, crisper highs, deep bass - similar to a cap change.
https://www.mundorf.com/audio/en/shop/Cables/MConnect_SGW/
@Jeffrey - I've used lots, most recently Mundorf SilverGold. Expensive, but when used internally one doesn't need much. Most recently I replaced the internal speaker wire from the board to posts on a Bryston 4B-ST, and achieved an amazing result. Better response, crisper highs, deep bass - similar to a cap change.
https://www.mundorf.com/audio/en/shop/Cables/MConnect_SGW/