X-Altra HPA-1 Class A Headphone Amplifier

Good quality solder makes a big difference. Kester solder is hard to beat, the best I have used is Cardas quad eutectic with Topnik RF800 liquid flux.

None of that lead free nonsense either ;)

Metcal MX500 system is the finest kit available, keep an eye on the bay as they come up quite often.
 
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passive420, thanks. In the past, I went the other direction (lead free) and had total frustration so glad to get the recommendations from both of you that will make the building a pleasure rather than a total chore with damaged parts and solder globs.
 
The one passive420 linked is 0.8mm diameter (at least the picture looks like it says 0.8mm on the roll). For 0805 I personally find 0.5mm to be more suitable. You feed slightly more solder wire and thus have more control over how much solder flows into the joint (so you can more easily get a good joint geometry).
 
The one passive420 linked is 0.8mm diameter (at least the picture looks like it says 0.8mm on the roll). For 0805 I personally find 0.5mm to be more suitable. You feed slightly more solder wire and thus have more control over how much solder flows into the joint (so you can more easily get a good joint geometry).

You're right sorry, didn't check the diameter. 0.5 would be better for smaller work. For anything else you will burn through a reel in a year.

Not to be too pedantic: you do not really 'feed' any solder when hand soldering SMD parts? With the part held in place, you tap the solder with the iron bit and transfer to the fluxed joint. With the right geometry bit a tiny blob can be controlled nicely.

Just checked my Cardas solder and it's 0.86mm, been using it for 6 years. It's more than fine, good solder and kit is the key to success.

That Kester is beautiful stuff to use, with RF800 flux and Citrus based cleaner you'll be producing your best work.

;)
 
Sorry off topic: I won't lie - I'm very proud of my soldering skills, OCD has it's advantages. I'll take a long time to place a component perfectly. Line them up like soldiers or don't bother...

Some of my best work, Sjostrom diamond buffers and EUVL's SHPP board, two of the more challenging builds in DIY audio !

I bloody love SMD projects. :)

Edit: Good vision helps, being able to see the little f**k**s helps immensely, these proved worth the money -
Headband Magnifier Glasses with 2 LED Lights and 5 Detachable Lenses 1X,1.5X,2X,2.5X,3.5X-USB Charging Hands Free Magnifying Glass for Close Work,Jewelry Work,Watch Repair,Crafts: Amazon.co.uk: Office Products
 

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I'm trying to think of another activity that requires stillness and concentration like SMD work... watchmaking comes to mind. You need to be pretty Zen to handle 0603 and below.

Fortunately Bonsai's layout and pad size is perfect for human assembly, very nice board to build really. I'm trying to think how to put one of these into a slim case, I would use pieces of alu flat bar between each BJT pair and sink to the sides of the case with L-brackets possibly.
 
Not to be too pedantic: you do not really 'feed' any solder when hand soldering SMD parts? With the part held in place, you tap the solder with the iron bit and transfer to the fluxed joint. With the right geometry bit a tiny blob can be controlled nicely.

You already said it: On a fluxed joint. If there is enough flux, pretty much any technique will make an electrical connection. I am more concerned about the quality of that connection, the amount of flux that has to be removed from the board afterwards and also the thermal stress on the components.

I usually use the tip to contact both surfaces and preheat them for like 1-2 seconds, then I feed solder directly to the joint and in a total of roughly 3-4 seconds the joint is done. Without any extra flux, but still with perfect geometry and surface finish. Works for 0603 and larger (for me).
 
Sounds like a clean method, I'll try it. Sometimes depending on position I'll pre tin a pad then slide the chip in quickly with a little heat, then clear the other side. Strategy is needed when lots of 0603 are close together ;)

I think xrk71 uses a gas heat pen and paste for smd jobs, for those QFN type packages it's useful, he also uses hot plates in an oven, something I wanted to try but seems a bit tricky.
 
Luckily for audio you can mostly avoid the packages that require practice and extra tools to hand solder successfully, although I have encountered layouts with tiny SOIC footprints that were a real pain to solder. Bonsai has used nice footprints for hand soldering and left enough space between the parts so you can clean it easily. For many of my SMD layouts an ultrasonic bath has become almost essential.

I see you also used some MELFs in your build, wise choice ;)
 
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I’ll make a short video this week on SMD soldering. The basic technique is

1. Put a small blob of solder on one pad only
2. Pick up the component with fine tipped tweezers
3. Touch the blob of solder on the pad and slide the component into position with the tweezers
4. Wait 2-3 seconds while the solder solidifies
5. Solder the other pad

And that’s it. Very quick and easy. Same technique for IC’s. Just solder one corner pin down the straighten the IC if required (use the tweezers) then solder the opposite corner pin, then do the rest. I can put down 0.5 mm pitch IC’s like this.

Att: you must use an ultra fine tipped pencil bit on your soldering iron, 0.5 to 0.8 mm diameter solder and you must have fine tipped tweezers.
 
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Sounds like a clean method, I'll try it. Sometimes depending on position I'll pre tin a pad then slide the chip in quickly with a little heat, then clear the other side. Strategy is needed when lots of 0603 are close together ;)

I think xrk71 uses a gas heat pen and paste for smd jobs, for those QFN type packages it's useful, he also uses hot plates in an oven, something I wanted to try but seems a bit tricky.

Here is how I do it with paste and $40 hot air pencil (SMT rework tool):XRKaudio SMT Method Demo - YouTube

For tricky VSON parts with no exposed leads, use a hot plate underneath to get to 130C. Perfectly safe for parts indefinitely. The when you blast it with hot air pencil it locally heats only that spot to liquify.

Here are some tips for tools to use:
BTSB Buffer - SE/Bal to SE/Bal Buffer GB
 
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Thanks for that X ;) Your work it notably good. It's fun to see the chips snap into place under tension. I'm finishing that exact bal board today.

Andrew those are 0603 parts, I did mine by hand and lost a resistor at the end. It arrived today.
 

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