I agree, I usually skip the breadboard version and go straight to the pcb until I find the best version.
And then in the end everything remains on that best prototype 🙂
And then in the end everything remains on that best prototype 🙂
These days, with very cheap pcbs that are easy to design, old style rats nest protos are obsolete.
I only use breadboards now for experimentation.
I only use breadboards now for experimentation.
For now it seems solved or almost, I've connected everything to the ground point of the DAC board close to the 1000 uF reservoir capacitors.
This aligator clips seem to have very high resistance, like 0.5 Ohm or so (measured in DC), I think that's too high for a ground connection. I've put 4 of them connecting to the battery GND.
I'm willing to go to the next phase and design a few PCBs to get rid of this mess. 😋
PS:
Is it possible to unsolder components on 2 or 4 layer PCBs? I've never been successful in doing that.
This aligator clips seem to have very high resistance, like 0.5 Ohm or so (measured in DC), I think that's too high for a ground connection. I've put 4 of them connecting to the battery GND.
I'm willing to go to the next phase and design a few PCBs to get rid of this mess. 😋
PS:
Is it possible to unsolder components on 2 or 4 layer PCBs? I've never been successful in doing that.
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Yes, the AD811s don't seem very comfortable they are heating up to about 50-60 ºC at +/- 12 V supplies, I've never used heatsinks on DIP packages, but this one seems to need one it is very hot to touch and I'm afraid that working at high temperatures might degrade performance and/or damage the IC.
They don't seem to make any noise, the noise floor measured with the soundcard of my PC (16 bit resolution) is under 100 dB on the spectogram.
I've also checked with the probe of my osciloscope and I can't see any oscillation.
I cannot tell about sporadic oscillations or very high frequency oscillations (at 100 MHz and above), any idea how to check for those?
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I would not recommend it. Maybe your first pcb could have IC sockets, and terminal posts or socket pins
in critical places. There are many kinds of those. An example:
https://www.digikey.com/en/products...acturing-corp./9019-0-19-15-06-27-10-0/437868
Sorry for making such a noob question, what are those connectors for? 😋
Never seen them before 😅
I've successfully made a 2 layer PCB with metalized holes once, it's the one for the HP amplifier, though I will never be able to recap it, well for now it is relatively new, but in the future it will be nearly impossible to change those capacitors.
That is a pcb mounting socket, that will fit a certain size wire or component lead.
Often used in phono preamps for holding cartridge matching capacitors.
You can use it for trimming a component like R or C that you are not certain of the value.
I would only plan on being able to unsolder components from plated through holes (without pcb damage)
if you significantly oversize the mounting holes.
Snap-in mounting components are much more difficult, and much more likely to cause pcb damage
when trying to remove.
Thank you very much rayma 😉
So for ICs I should use sockets, right?
The mounting sockets are for used for which components? Resistors and capacitors? Should I use for all or only for the ones that tend to have a shorter life?
Maybe some pin connections, like those found in microcontroller boards, with the ability to be bypassed or opened with jumpers can also add some extra flexibility to the PCB what do you think?
Which heatsinks can be used for DIP packages and how are they held in place?
Do you think the regulators also need heatsinks? They also heat up to 60-70 ºC!!!
So for ICs I should use sockets, right?
The mounting sockets are for used for which components? Resistors and capacitors? Should I use for all or only for the ones that tend to have a shorter life?
Maybe some pin connections, like those found in microcontroller boards, with the ability to be bypassed or opened with jumpers can also add some extra flexibility to the PCB what do you think?
Which heatsinks can be used for DIP packages and how are they held in place?
Do you think the regulators also need heatsinks? They also heat up to 60-70 ºC!!!
Well, if you suspect that you may later have to remove a particular part in order to get the pcb working,
then install a socket for it. Please don't expect to just solder on all the parts, and it will work perfectly.
That is not the typical thing that happens. Usually there are layout errors, wrong footprints, etc.
that have to be fixed. Sometimes you will have to make several iterations of the pcb.
So do whatever you think will work best for you. Of course, sockets of any kind are not ideal for HF performance.
but you may need them to get it working in the first place.
then install a socket for it. Please don't expect to just solder on all the parts, and it will work perfectly.
That is not the typical thing that happens. Usually there are layout errors, wrong footprints, etc.
that have to be fixed. Sometimes you will have to make several iterations of the pcb.
So do whatever you think will work best for you. Of course, sockets of any kind are not ideal for HF performance.
but you may need them to get it working in the first place.
Thank you very much for your patience and quick reply,
I only got a PCB design right at the first time once in like 10 attempts or so, having this in mind I think this will be a long way.
I think it is a good idea to use sockets for expensive components, keeping in mind that the PCB design may not work well at the first atempt, this applies to the DAC ICs (AD1862) and maybe also for the AD811s, in my opinion it is not so important for the regulators for example.
I only got a PCB design right at the first time once in like 10 attempts or so, having this in mind I think this will be a long way.
I think it is a good idea to use sockets for expensive components, keeping in mind that the PCB design may not work well at the first atempt, this applies to the DAC ICs (AD1862) and maybe also for the AD811s, in my opinion it is not so important for the regulators for example.
I don't know if I should make another thread to discuss this or not, but I've tested an unregulated power supply in this design and I can only hear 50 Hz hum. I've tried to add regulators for the HP amp and the tone control circuit and it doesn't improve much. Maybe I should keep the batteries as power supply, since they provide a much cleaner voltage supply. The main problem with the batteries is that they don't last for more than about 2-2.5 hours on a full charge.
Unregulated supplies should only have 100Hz or 120Hz hum, due to full wave rectification.
If a regulator does not help, then ground loops or poor connections would be likely.
There's no reason to spend days and weeks trying to fix a crude breadboard mock-up. Just go for it.
A decent pcb layout should take care of the noise.
If a regulator does not help, then ground loops or poor connections would be likely.
There's no reason to spend days and weeks trying to fix a crude breadboard mock-up. Just go for it.
A decent pcb layout should take care of the noise.
The preamp pcb should be no problem with just two layers.
The DAC board is more problematic. Besides the DAC being obsolete, it requires four power supplies, and split
ground planes. I would check around for a board design that someone has already done and maybe has gerbers available.
https://www.diyaudio.com/community/threads/ad1862-pcb-layout.254063/
But why not this board?
https://www.diyinhk.com/shop/audio-...sampling-nos-audio-dac-with-fifo-reclock.html
The DAC board is more problematic. Besides the DAC being obsolete, it requires four power supplies, and split
ground planes. I would check around for a board design that someone has already done and maybe has gerbers available.
https://www.diyaudio.com/community/threads/ad1862-pcb-layout.254063/
But why not this board?
https://www.diyinhk.com/shop/audio-...sampling-nos-audio-dac-with-fifo-reclock.html
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I think I can base my DAC board on the lastest version of miro1360, if he allows me to do so, but I want to simplify the logic section and modify the I/V stage to be able to accommodate a CF opamp, like the AD811.
The preamp board I will try to design myself from scratch.
The preamp board I will try to design myself from scratch.
Sorry for asking again, someone has a PCB design for the AD811 I/V stage alone? Which heatsink should be used for the PDIP package and how is it fastened?