SDG

[@sdgelectronics]

PCBWay 3D Printing and Fabrication: www.pcbway.com/rapid-prototyping/

[@brianwood5220]

Hi, Steve. For anyone who has one of these, this video will be like the holy grail of how to fix them. I bet the views go through the roof. Anyway, thanks for sharing.

[@IanScottJohnston]

I wonder if the "Cambridge Butcher" is watching.......what a mess! Nice repair Steve.

[@Janktzoni]

'mess' is an understatement 🤣. An apprentice bricky with a trowel and some mortar would have done a cleaner job.

[@electronash]

@IanScottJohnston - The original 'mod' job made me sad. :(

[@tolgadabbagh1877]

most professional repair job i watched on youtube

[@romancharak3675]

Almost looks like "Factory", after your rework, Steve. NICE!

[@flashback9966]

We use to include a small internal fan, just to stir up the air inside our radar receivers. This was very effective in preventing hotspots. Might help here to keep this lovely unit running well into the future. BTW nice clear video :)

[@NotMarkKnopfler]

I was thinking exactly the same - might be worth modifying the case such that some air cooling (just a weak draught is better than nothing) can drift across those components. I would imagine the cumulative effect of those quite hot components would contribute towards a little oven inside that case! Definitely room for improvement.

[@andymouse]

Awesome work, really nice job to do as you found the fault and then cleaned up the mess. Very satisfying !

[@christianlett]

What a horrible butchered hack job you started out with - but a great repair, leaving it in a vastly improved state. Nice Nichicon Muse bipolars too!

[@DimRoditis]

Excellent, analysis, repair and info! Thank you very much.

[@TechStuff365]

Great job, I'm amazed a faulty cap could make noise like that. The wall wart PSU was recalled by Cambridge audio as the plastic case can fail exposing live parts.

[@michelaarssen1520]

Thanks for sharing the video, I've fixed mine by replacing the small 10uF capacitor

[@sdgelectronics]

@@michelaarssen1520 great to hear!

[@tszaboo4952]

Cool video. I had to do the same repair to a DADMagic plus I just bought, that the seller sold as "flawless".

[@dsesuk]

A quality repair. Good to see how it should be done properly too following the hack job that had happened prior.

[@mikepxg6406]

Excellent job. Is this a job you would recommend doing on a working unit as a preventative measure. By the way I had some blue LED's fail on mine but I replaced those some years ago.

[@sdgelectronics]

@@mikepxg6406 I would leave it until you have issues. The surface mount electrolytic capacitors can be difficult to remove without the right tools and risks damaging a unit that's still ok

[@Mr.Leeroy]

fist time I see SMT film in product, and ofc it is audiofillery. keep up🤘

[@alexandergreenfield91]

Very impressive work and beautiful narration. Liked and subscribed. As a man that clearly knows his onions, can you recommend any particular brands / models for a great HD dac at a reasonable price. I was considering both Cambridge audio and the topping. Any thoughts?

[@MattNeighbour]

That brought back some hi-fi development memories ! It still irritates though that Cambridge Audio has nothing to do with Cambridge. My designed-in-Waterbeach Arcam rDac engineering sample is still going strong and I must say it has a much more compact design. Single DAC IC but the WM8741 which does sound noticeably better. And I always ended up melting something when replacing caps during development listening sessions!

[@johnshaw359]

That was where in the founders in the 1960s, Cambridge Audio began life as a division of Cambridge Consultants in 1968 were educated.

[@sdgelectronics]

Nice to hear from you Matt. I have a couple of Arcam amps for repair, but it looks like Arcam dissolved in 2019, so they are gone now from Cambridge along with any kind of customer service. Harman (Samsung!) seem to own the brand and probably lost the essence of the original products!

[@MattNeighbour]

@@sdgelectronics the algorithm sent me a few of your videos recently, good stuff. I knew Harman bought Arcam and they left the original Waterbeach factory site, but I thought there were still a handful of engineers on the newish business park across the road. Might have to ping a contact to find out!

[@MattNeighbour]

Wolfson was absorbed into Cirrus Logic I think (or similar larger semi co) that later dissolved the site and now I have ended up with a manager who used to work there, as Kandou have a semiconductor manufacturing operations team in Scotland.

[@reveal1693]

Thanks for the repair video 👍.

[@BobRoger-i8z]

Great job, nice professional video.👍

[@TechStuffGuy]

Usually adding zoom lens makes temperature readings somewhat higher if there is no correction in menu for that (Noticed this when I made E4 hacks and menu in EEVblog)

[@sdgelectronics]

I'll have to check this, it didn't seem too far off with/without the lens.

[@jaro6985]

Do you know the reason why?

[@estebanblascotrasobares8755]

Great work

[@davadoff]

I’d like to learn more about the charge pump section: ICs, filtering & noise. I’d use external 12v AC PSU instead (a transformer) and no charge pumps. But maybe their way is better overall.

[@sdgelectronics]

I suspect it's something to do with energy requirements - transformer-based power adaptors are pretty much gone from new equipment.

[@tomasparrado873]

I could be wrong but are the relays at the outpus just a delayed connect so you don''t get a pop on switch on. As well as the reasons you gave Edit: You mentioned stopping speaker pop later, I just hadn't got there in the video yet

[@alexandergreenfield91]

Would you be able to modify the dac to have an even cleaner voltage reference in for even less signal distortion?

[@lattehour]

more repair videos specifically on complex equipment

[@davadoff]

I’d love to see more analysis & reverse engineering & teaching too. I didn’t even know about those sensitive SMD caps 🤔

[@lattehour]

@@davadoff me neither now i get it why i destroyed a few , i had a hunch they could not stand the head but did not knew exactly what type they where

[@DustinWatts]

@10:43 That Wurth capacitor seems to be loose, it moves quiet a bit when you bumped it :)

[@sdgelectronics]

That's the one with the lifted pad. All sorted now though!

[@DustinWatts]

@@sdgelectronics Yeah I saw it. and furthermore, nice job!

[@OKuusava]

Nice video, of course muted as "music" but still.

[@daniellu9106]

I have one of this DAC, the only issue is the LEDs for sample rate are all dead.

[@adamdavies163]

I repaired a bunch of those a few years back, every one of them had failed blue LEDS. Must've been a bad batch of LEDS or they were overdriven.

[@RickRuizAudio]

Hey Steve, by chance would you have a recommendation for a repair tech in California, USA? My Cambridge 851N is giving me trouble.

[@apr888]

Great job with the repair! Bad design though from Cambridge Audio. No proper heat management on the linear regulators that are probably driven so close to max current.

[@jedi-mic]

Nice di you want to sell it? Whereabouts are you based in the UK

[@abeleski]

I would also put some glue at base of that cap with the loose pad.

[@davadoff]

Yeah I was expecting him to do that instead of the wire. Superglue would be ok?

[@sdgelectronics]

Before putting it back together, I put a blob of glue between the capacitor case and the edge of that IDC connector.

[@JBits-m9p]

brilliant work, but its probably not worth it, at least subjectively the sound from CA dacs would be described as "sterile"

[@twitchbook-1]

was the feed of the bclk than cause issues in ppl thanks

[@TheEmbeddedHobbyist]

What's your room temperature 60°c seems a bit excessive for an opamp.

[@davadoff]

That room is usually intolerably hot (30*C)

[@TheEmbeddedHobbyist]

@davadoff that explains it, the chip is only 30°C above ambient. In 😀

[@sdgelectronics]

Air conditioning was on, so it should have been around 21C

[@TheEmbeddedHobbyist]

@@sdgelectronics Designing a circuit where an opamp runs about 40°C above ambient seems a bit strange. is there another fault or just bad design.(IMHO)

[@sdgelectronics]

@@TheEmbeddedHobbyist Under no load, they're dissipating around 0.5W, so you'd expect the temperature to be raised to some extent. The OP275 used at the last stage use less power and correspondingly have a reduced temperature, so I think it lines up.

[@curtlundgren6867]

A great video, but if you must run background music, please run it at a low level.

[@davadoff]

Agreed! Although no music would be better, with ASMR style repair noises instead.

[@FriendlyIntentions]

Why not just replace em with MLCC's? the 1206 MLCC"S fit perfectly in that footprint haha

[@sdgelectronics]

Went for 1210's in the end!

[@FriendlyIntentions]

@@sdgelectronics Good choice. When I design switching regs i NEVER use electrolytic for input or output primary caps, You can always do ripple reduction with MLCC's then stack electrolytic for bulk capacitance but even with 3-4 MLCC's you can get output ripple 1mV ptp with 4 22uF MLCC caps and those are cheap and easy to package.

[@codernov]

Ohhh. You using Peak ESR. I'm using Hantek. For really tiny stuff NanoVNA H4. I know industry standard is DE-5000.

[@sdgelectronics]

@@codernov the ESR70 works really well. Jez does a great job at Peak.

[@helmut3356]

eBay :o)

[@r423sdex]

What’s the point of repairing it, you can buy one for £50 that would perform better.