Awsome!! What type and size of reamers did you use? Were they tapered hand reamers?
Yes, it is a hand reamer, tapering from 1/2 inch to about 1/16th of an inch over a distance of 4-5/8th inches. I bought it in the 1970's for 2 or 3 USD. I have no idea what one would cost today. See the photo in the original post.
matthaios - you did pretty well for the first time with a soldering iron!The small 1/8 watters can be hard to spot a bad joint on, even with a magnifying glass. Reheating solder joints in a suspect area is always a good first step to try.
The above is really good advice--a magnifying glass and/or eye loupe (4X - 8X) can be really useful for checking for soldering problems. That's especially true for those who wear glasses or contacts. Fine solder bridges can be difficult to see with the naked eye--especially where the spacing is really close like the O2's regulators and MOSFETs.
And I agree those who built an O2 as their first DIY project have a lot to be proud of. It's not a trivial build with nearly 80 components and a fairly cramped PC board layout.
I think the thing you need most when assembling O2 is attention. O2 is my first serious project (not the first time I hold solder iron, though), and I have to say it is awesomely designed and extremely easy to build (thanks again, RS! ) There are no SMD parts (my personal opinion - you have to be a neurosurgeon to solder those by hand), there are no closely located pads that would be easy to bridge... Consider this: the tip of my iron is 3.5 mm in diameter, and I have no skill, and I have assembled it right with the first try! I didn't have to re-solder a single part! If I can build it - everyone can build it.
It is indeed much harder if you need optical devices to see clearly, though.
) There are no SMD parts (my personal opinion - you have to be a neurosurgeon to solder those by hand), there are no closely located pads that would be easy to bridge... Consider this: the tip of my iron is 3.5 mm in diameter, and I have no skill, and I have assembled it right with the first try! I didn't have to re-solder a single part! If I can build it - everyone can build it. It is indeed much harder if you need optical devices to see clearly, though.
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+1 - although if you ever do have to solder SMD parts, particularly those with multiple pins, it can be effectively done by sticking the part accurately in position with a very small blob of hot melt glue, then soldering the part into place without worrying about bridging any pins, and finally removing excess solder with desoldering braid, which then unbridges the pins.
After receiving the front panels from the GB (thanks @Flynhawaiian!), I finished my second build last night and everything passed with flying colors.
I thought I had a strange voltage issue at first, but then realized I had temporarily forgotten that the pin locations on DIP8 packages count in anti-clockwise fashion, not columnar.
Thanks again, RS. You've really made it easy to enjoy both the build process and the end results. Now Santa just needs to bring me some new cans for Christmas so I can REALLY appreciate it.
I can't even fathom the amount of time you've given to this project (the documentation alone is jaw-dropping), and just really want to say a heartfelt THANK YOU for everything.
I thought I had a strange voltage issue at first, but then realized I had temporarily forgotten that the pin locations on DIP8 packages count in anti-clockwise fashion, not columnar.
Thanks again, RS. You've really made it easy to enjoy both the build process and the end results. Now Santa just needs to bring me some new cans for Christmas so I can REALLY appreciate it.
I can't even fathom the amount of time you've given to this project (the documentation alone is jaw-dropping), and just really want to say a heartfelt THANK YOU for everything.
Don't be afraid of SMD work. I have come to almost prefer it. Once you get the hang of it... I think you might like it better than through hole! Just think no more leads to trim!! Try a Grub DAC, a good entry into SMD and a fine sounding low priced piece of kit that will go nicely with your ne O2!!
billyk, my hand is just not steady enough for SMD, it shakes too much. I'd prefer to cut the leads, at least that's possible for me
Yeah, I use a clip to hold the part in place while I solder it. I need to get a sharper tip for my Weller though. It's not an easy task and I can't do it without a magnifying glass.
I'm starting to prototype my future DAC, specifically - it's output stage (not much else to prototype once the DAC chip and input receiver is chosen, I guess). It will be plugged in to O2 (obviously ), and my question is: how high a gain can I set without degrading sonical performance? Or, in other words, how low can I push input voltage? Ideally, I'd like to make input voltage as low as 0.1V, which would require gain of ~20. On the other hand, I understand that it would lower S/N ratio significantly, and, I guess, getting input of 300mV and lowering gain to 7-8 might be better. What do you think?
), and my question is: how high a gain can I set without degrading sonical performance? Or, in other words, how low can I push input voltage? Ideally, I'd like to make input voltage as low as 0.1V, which would require gain of ~20. On the other hand, I understand that it would lower S/N ratio significantly, and, I guess, getting input of 300mV and lowering gain to 7-8 might be better. What do you think?
I'm starting to prototype my future DAC, specifically - it's output stage (not much else to prototype once the DAC chip and input receiver is chosen, I guess). It will be plugged in to O2 (obviously
That's unconventional. What has influenced your thinking? Are you trying to bypass an I/V stage from your DAC?
At first I want to evaluate the simplest output stage design, which is resistor-based I/U converter. The lower the resistance - the better in terms of DAC linearity, but the lower the output voltage(obviously). Ideally, the resistance should be zero, but upon investigation of some forums I figure I can get 0.1-0.3V (30-100 Ohm) without significant performance degradation.
And I have missed 1 detail - the DAC has differential output, so I'll use an op-amp anyway, and I should choose it's gain, too. So, I'd like an advice on balancing DAC's output gain vs O2's gain. I understand it's a long shot with the amount of information I have on the circuit's characteristics (which is effectively none), but any guess is appreciated.
@Alexium, I don't know of a DAC that's not differential output. I'm under the impression that the linearity problems can be solved by a clean I/V stage instead of output resistance. The added noise floor should still be far lower than anything you're going to deal with from extreme amplification of a weak signal. Clean DAC + I/V implementations can approach (maybe exceed) 115dB SNR.
Is this an ESS DAC? It sounds like one.
Even if the DAC had SE output (maybe some do?), since the O2 has 10kΩ input resistence, what does that do to the DAC's output voltage spec?
Is this an ESS DAC? It sounds like one.
Even if the DAC had SE output (maybe some do?), since the O2 has 10kΩ input resistence, what does that do to the DAC's output voltage spec?
I believe there are all kinds of DACs there - with I and V output, differential and single-ended. I'll try to come up with an example tomorrow.
Of course! But that's not the point. The point is to move from simple to more complex designs to determine the top of my hearing abilities
Nope. In fact, ESS DACs are not popular or well-known where I live. I have first heard of this manufacturer only few months ago.
I'm prototyping with PCM1798, and when I determine the final design, I'll try to make a nice clean DAC based on PCM1794, perhaps even dual-mono 1794.
Nothing at all, except the need to match gains to get sufficiently loud signal on O2's output. I clearly understand this is off-topic, but I think it's a great thread to get valuable advice, so I took the risk
The PCM179x chips are great. Isn't it interesting how most all of the modern DACs aren't as good as the ones created 6-12 years ago?
This makes me wonder how the ODAC is coming along. I'm itching for details.
RocketScientist, aren't you expecting some newly minted boards any day now for your next round of testing?
This makes me wonder how the ODAC is coming along. I'm itching for details.
RocketScientist, aren't you expecting some newly minted boards any day now for your next round of testing?
I just wanted to say a big thank you to everyone who have posted tips and tricks on how to make a face plate, with only the minimum of tools. I do not think I could have come up with eve half of this on my own.
This is the first time I've tried drilling into aluminium, and I think it proves that as long as you do not expect boutique quality looks and perfect alignment, there's nothing stopping you doing it on your own.
This is the first time I've tried drilling into aluminium, and I think it proves that as long as you do not expect boutique quality looks and perfect alignment, there's nothing stopping you doing it on your own.