I had planned to progress my SLOB speaker project today but with the inclement weather that wasn't really on so I spend a few hours putting my first RTZ DAC board together - soldering was with my hot air workstation so most of the time was spent applying solder paste (oh for a solder stencil!) and placing the components. I've inspected the board under my USB microscope and I'm pleased with the results, I only had to deal with a couple of solder bridges - time will tell if everything survived the soldering 😟
Still some parts to do when I get them and there's the bottom of the board to do too.
Still some parts to do when I get them and there's the bottom of the board to do too.
I foresee a SMT hot air station in my future.. I have some other SMT stuff on the design books (including a very low noise power supply). I tried to desolder a few components from an old m-Audio firewire device (including an NSK 24.576MHz oscillator) and it didn't go too well..
I've been practising on some cheap 'learn how to weld' kits from AliExpress and results are improving but not perfect yet - I screwed up soldering the Spartan chip on the simple DSD Modulator project trying to clean up some solder bridges! The main lessons I've learned is to be frugal with the solder paste (that's hard when applying it by hand from a syringe) and to take my time placing ICs, transistors, and the like.
This is the solder paste I use;
https://www.mouser.co.uk/ProductDetail/Chip-Quik/TS391SNL?qs=1mbolxNpo8d4uTdccbPJPg==
I would really like to get a small reflow oven to get more control of the heating/soldering cycle.
Yes, the syringe approach is hard work - thanks for the link, I think I'll invest in one of them - it might even allow use of a smaller bore tube so even less solder paste dispensed...
Hey all--well late to the party on hearing about this but I figured I'd shoot my shot and ask anyway; anybody out there with spares they'd consider selling? 1 DAC board, 1 filter.
I have a spare DAC and filter board I am not going to need. Tell me where you're located and I'll get a shipping cost.
For group buyers, I'm still holding two spare DAC PCBs, which I'll hold for a couple of months as insurance for anyone messing up on the soldering, after which I'll make them available on Marketplace. I don't have any spare filter boards but these are just two-layer so not too expensive to order another five if they're needed.
@nautibuoy:
Well, if you will allow me to say so .. I think your SMD mounting looks very neat, indeed 😉 ... Wondering though how you managed to place the components with such "alignment"? Did you have some kind of "alignment tool" or did you accomplish this by hand - maybe with a tweezer of some kind? Also, I am not entirely sure what "oh for a solder stencil!" means: does it mean that you would really appreciate having had a stencil - or does it mean that you had & used a stencil?
BTW I have just ordered one of these: https://smartpid.com/store/#!/Smart...tat-application/p/123201984/category=32120511
... which I will be using for my reflow oven - first time (it is a combined vacuum & reflow oven) - so I would appreciate if you have a tip particularly on an aligned placement of the components.
BTW to those of you considering a reflow oven ... I take it you know about the Controleo solution? https://www.whizoo.com/ ... As far as I can see it is considered a well-working and not too expensive reflow setup ...
Cheers,
Jesper
Well, if you will allow me to say so .. I think your SMD mounting looks very neat, indeed 😉 ... Wondering though how you managed to place the components with such "alignment"? Did you have some kind of "alignment tool" or did you accomplish this by hand - maybe with a tweezer of some kind? Also, I am not entirely sure what "oh for a solder stencil!" means: does it mean that you would really appreciate having had a stencil - or does it mean that you had & used a stencil?
BTW I have just ordered one of these: https://smartpid.com/store/#!/Smart...tat-application/p/123201984/category=32120511
... which I will be using for my reflow oven - first time (it is a combined vacuum & reflow oven) - so I would appreciate if you have a tip particularly on an aligned placement of the components.
BTW to those of you considering a reflow oven ... I take it you know about the Controleo solution? https://www.whizoo.com/ ... As far as I can see it is considered a well-working and not too expensive reflow setup ...
Cheers,
Jesper
Hi Jesper. All the part placement was done by hand with tweezers - I obviously pay most attention to the ICs but less so for the caps and resistors as the surface tension of the molten solder will help to get them neatly aligned. My comment about a stencil was wishing I had one as it would have made 'pasting' the PCB so much quicker and with just the right amount. I'm hoping the tool linked to in post #365 will save a lot of time when I do another board.
I have a friend with a reflow oven so I may ask a favour...
I have a friend with a reflow oven so I may ask a favour...
Hi Ray ... & many thanks for your feedback. Interesting that the molten solder helps in getting the components aligned to such an extent - I reckon this phenomenon will make things simpler and more aesthetically pleasing (and maybe also the #365 tool) ...
Cheers, Jesper
Cheers, Jesper
Most of them - but I get the impression that the newer boards are still rather "fresh" in the development cycle, so fully built-out systems (with power supplies and enclosures) are still WIP. My apologies if this is incorrect.
I had another look at this today. I inserted caps between the DAC board output and the 'CD Enhancer' inputs but the result is exactly the same as before, just a hum and no music. The 3A5 is a DHT so the hum can probably be worked on if I can find out what its doing with the music. I reinstalled the op-amp filter board and normal service was resumed.
Electronics theory is a strong aspect of my participation in this hobby but this morning I have been mulling over the CD Enhancer situation. I know the anode supply is good (a little higher than the schematic at 124V but still within the 3A5 spec) and I know the cathode/filament is being heated. I also know that the DAC board is outputting valid signals (because it works with the op-amp filter board). I also know that the breadboard of the circuit follows the schematic. So, I'm thinking that the issue must be grid related so today I'm going to try and get my head round grid biasing and start taking some measurements. Thoughts?