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Best Upgrade ever!

booja30 said:
I didn't have any problem with your project -- fixing some bad joints sounds like something that would have the potential for far more impact than a high end cable.

It's just the thread title was a bit mysterious and sensationalist, and then the thread itself has very little info. I asked what kind of amp because it would be interesting, for example, to know how old it was. Or what type (SS vs valve), or what model. It seems like a secret for some reason.
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Far from it the amp in question was a tired old 1971 Sansui au-101 that had on the face of it iffy 2sc871 transistors,a common fault which are often replaced,though in this case resoldering the joints not only managed to save the original transistors but bought about an overall benefit to the sq
 
Mike P said:
Dry solder joints are a very common issue and if I'm 'going over' a piece of kit I'd be sure to check carefully for dry joints, especially in the usual suspect areas. I'd call it a repair rather than an upgrade though. There's surely no benefit in reflowing a perfectly good joint.
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It can be,though what harm can reflowing all of the joints be?
 
retrospective said:
It can be,though what harm can reflowing all of the joints be?
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No, I can't see any harm in it other than being a waste of time. I'm lucky enough to have very good eyesight and can spot the bad ones easily enough, so I tend to be very selective rather than taking a shotgun approach.
 
Mike P said:
No, I can't see any harm in it other than being a waste of time. I'm lucky enough to have very good eyesight and can spot the bad ones easily enough, so I tend to be very selective rather than taking a shotgun approach.
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I would suggest that the inexperienced would have no clue what to look for though
 
retrospective said:
Far from it the amp in question was a tired old 1971 Sansui au-101 that had on the face of it iffy 2sc1871 transistors,a common fault which are often replaced,though in this case resoldering the joints not only managed to save the original transistors but bought about an overall benefit to the sq
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BTW I'm a Sansui fan myself. I've never seen or heard an AU-101 but they look really nice. I love that Sansui was making black boxes when everyone else seemed to be doing silver.

One of my many lockdown projects last year was an overhaul of an AU-717. A soothing and rewarding project!
50632735153_a0aa757475_c.jpg
 
booja30 said:
BTW I'm a Sansui fan myself. I've never seen or heard an AU-101 but they look really nice. I love that Sansui was making black boxes when everyone else seemed to be doing silver.

One of my many lockdown projects last year was an overhaul of an AU-717. A soothing and rewarding project!
50632735153_a0aa757475_c.jpg
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I heard both Sansui and the 717 is way way better, it’s a night and day difference, at least in their stock form.
 
retrospective said:
I had you down as knowing a thing or two..evidently not!
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A dry joint is a fault. It will usually cause intermittency and crackles and sometimes result in no sound if bad enough. An amp with no dry joints will not be changed in any way by having all its perfectly good soldered joints remade.
 
I've had to reflow the solder in car binnacle boards and boards from games consoles using a hot air paint stripper. This was because the brittleness of lead free solder causes micro breaks in these filigree circuits. I would have thought similar failures in ageing hifi equipment would present in a similarly binary fashion as Jez says. It's very unlikely to present as progressive failure.
 
The Sansui is old enough that it will be using classic tin/lead solder.
Reflowing a joint that has been dry for a long time rarely works, you have to remove the old solder and clean up the oxidized component lead.

Touching up a joint MAY have a short term effect on an electrolytic that is at the end of its life
 
An interesting thought, I can’t imagine it ‘upgrading’ a piece of equipment in any way, it’s only going to repair and bad joints as said (and I’m sure there may have been a few!)
Jez could have agreed and then offered the service too if he wasn’t so honest,

“£150 solder reflow service.. improve ‘every’ contact for obvious and instant results!!”


If this made it into mainstream foo there would be an absolute fortune to be made..

Furthermore, removing the amp from your system, unplugging all the RCAs, living without it for a week and refitting speaker cables with fresh contacts and then powering up will bring greater benefits.

One thought - I recently cleaned up the contacts on the protection relays in my amp - unsoldered the relays, removed the covers and used some wet&dry paper to clean either side of the contact points.. these went from tarnished contact points to clean shiny copper and I’m certain that this made a difference...
 
Rug Doc said:
“£150 solder reflow service.. improve ‘every’ contact for obvious and instant results!!”

If this made it into mainstream foo there would be an absolute fortune to be made..
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I don't think so. The reason I think foo is so attractive and sells so well is that it's mostly plug and play. Forget everything inside your boxes, and focus on things anyone can install/swap. Cables, fuses, regenerators, ground boxes, etc. Maybe there's some DIY satisfaction in buying an expensive thing and 'installing' it yourself. There are individuals and businesses that do improvement work inside boxes (e.g. cap upgrades, circuit mods). But these aren't sexy enough because:
  • You can't sit across the room and admire it (visually)
  • Buying something is sexier than having someone else improve something you already own
  • It doesn't come in nice packaging so there's less sense of gratification/retail therapy
  • Mods don't get covered or advertised in magazines, just DIY websites for the most part
This is just speculation in my part... :D
 
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booja30 said:
I don't think so. The reason I think foo is so attractive and sells so well is that it's mostly plug and play. Forget everything inside your boxes, and focus on things anyone can install/swap. Cables, fuses, regenerators, ground boxes, etc. Maybe there's some DIY satisfaction in buying an expensive thing and 'installing' it yourself. There are individuals and businesses that do improvement work inside boxes (e.g. cap upgrades, circuit mods). But these aren't sexy enough because:
  • You can't sit across the room and admire your purchase (visually)
  • Buying something and fitting it yourself is sexier than having someone else improve something you already own
  • They don't come in nice packaging so there's less sense of gratification
  • They don't get covered or advertised in magazines, just DIY websites for the most part
This is just speculation in my part... :D
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The other attractive thing about foo is that it doesn't require you to replace any of your precious components. So the legendary EnglishMegaAudio amplifier that you have had for 20 years won't have to go, you can keep it.
 
What could possibly go wrong with this?

In the hands of someone competent with a soldering iron reflowing good joints wouldn't make a blind bit of difference

In the wrong hands a perfectly good amp could end up screwed!!!
 
PhilDick said:
Were they the 'spares' when you had finished?
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Yep. You can still see the corrosive glue on some of the medium sized caps.

I still have them in bags, but don't know why exactly. Some people sell the old components on eBay and people pay a lot for them for some reason! I measured the PSU caps and they were varied between half and 2/3 of the marked capacitance (not consistent with each other). I guess a vintage repair shop might keep stock for repairs where the customer didn't want a full overhaul.
 
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