And the extra resistor(s) will dissipate a lot of power so you need choose their mounting positions carefully. And you'd probably want to buy several more resistors than you actually need, to hand-measure and then extract the best matched pair or quad. This operation requires a rather expensive benchtop 5.5 to 7.5 digit DMM with 4 probe Kelvin connections. Of course, all of these difficulties can be overcome, but not many hobbyists have the necessary equipment and experience.
I think that Claude hit on my solution (well actually properly worded my proposal): bi-amping, with each amp having its own filter from the SMPS.
Mark, what you said makes total sense. I'm not really excited about 4 wire resistance measurements to match ballast resistors. Although i have access to the instruments, i'm not typically the guy using them
I suppose I'm still working out where in my "mental model" this filter belongs. Is it an overlooked part of the SMPS or is it the first step of supply filtering for the "load".
I know that the answer is probably "yes"
All of my experience with electronics comes from working with/designing scientific instruments. We typically just purchase our way into stable supplies ($$$$) and go from there. All of this consumer grade stuff is really new to me. My mind is typically used to going from good--> really good.
It seems that the issues i've been having with these DIY audio boards are going from "barely good enough" --> good --> (with potential for really good)
Enough philosophy! Thanks for the help
Mark, what you said makes total sense. I'm not really excited about 4 wire resistance measurements to match ballast resistors. Although i have access to the instruments, i'm not typically the guy using them
I suppose I'm still working out where in my "mental model" this filter belongs. Is it an overlooked part of the SMPS or is it the first step of supply filtering for the "load".
I know that the answer is probably "yes"
All of my experience with electronics comes from working with/designing scientific instruments. We typically just purchase our way into stable supplies ($$$$) and go from there. All of this consumer grade stuff is really new to me. My mind is typically used to going from good--> really good.
It seems that the issues i've been having with these DIY audio boards are going from "barely good enough" --> good --> (with potential for really good)
Enough philosophy! Thanks for the help
Filter for raspberry pi
Here is a photo of Mark"s filters installed in my raspberry subbu dac player using Moode audio software.I am using a Meanwell smps feeding the raspberry.I tried a Salas bib v1.1 power supply for the dac but preferred the original kit supplied one.I also tried A Meanwell with filter on the dac but it did not surpass the original.Using a filter for the smps feeding the raspberry improved the sound of instruments and vocals giving them more presence and realism.When I cut into the usb cable to power the ssd drive from the smps with filter instead of the raspberry pi usb port things improved further.I heard more details in the background and the soundstage improved.A big thanks to Mark for sharing his work.And I agree with Jean Paul about using linear low noise power supplies for dac"s.I will now retire my Aya tda1541 dac and shigaclone transport for the convenience of an ssd drive with my entire music collection at my fingertips.
Here is a photo of Mark"s filters installed in my raspberry subbu dac player using Moode audio software.I am using a Meanwell smps feeding the raspberry.I tried a Salas bib v1.1 power supply for the dac but preferred the original kit supplied one.I also tried A Meanwell with filter on the dac but it did not surpass the original.Using a filter for the smps feeding the raspberry improved the sound of instruments and vocals giving them more presence and realism.When I cut into the usb cable to power the ssd drive from the smps with filter instead of the raspberry pi usb port things improved further.I heard more details in the background and the soundstage improved.A big thanks to Mark for sharing his work.And I agree with Jean Paul about using linear low noise power supplies for dac"s.I will now retire my Aya tda1541 dac and shigaclone transport for the convenience of an ssd drive with my entire music collection at my fingertips.
Attachments
Minimalist
A snug fit - I had to file down both edges of the board to fit it in.
The cable came with an iFi Audio ipower, snipped in half.
Should I be concerned about heat, using it for B1-K pre-amp, so 24v and <100mA? It doesn't feel warm, with an hour's use.
To early to evaluate any changes to the sound, but no smoke so I'm pleased.
Thanks Mark and Konst for the board.
A snug fit - I had to file down both edges of the board to fit it in.
The cable came with an iFi Audio ipower, snipped in half.
Should I be concerned about heat, using it for B1-K pre-amp, so 24v and <100mA? It doesn't feel warm, with an hour's use.
To early to evaluate any changes to the sound, but no smoke so I'm pleased.
Thanks Mark and Konst for the board.
Attachments
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Hi, everyone. Just a reminder that I have quite a few boards here, ready to send out. If you want one or two and are in the US, then they are free. If you want more than two or are not in the US, then I'll ask you to toss me a couple bucks to cover the costs (60 cents per board) and shipping (usually just a first class letter, though more than three boards takes it over an ounce). PM me if you want some.
Note also: Mouser BOM here for one click ordering. This does not include DC jacks, etc, as on the original BOM.
Note also: Mouser BOM here for one click ordering. This does not include DC jacks, etc, as on the original BOM.
LM723 can be very good when implemented right. Also nice that a simple linear design with a decades old IC wins from SMPS even with an added filter. Noise that is not created does not need to be filtered
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If I spotted it correctly you are using some perfboard DC-blocker on the mains side. You may omit them as DC-content on mains voltage does not harm smps at all - keep in mind they do a mains rectification as a first step
Thank you Mark Johnson ...
... for making (amongst other things) this well thought-out PCB available to the public, including publishing the gerbers so that anyone who sees fit to do so can duplicate and distribute them.
I therefore, as a tribute, can offer 14 PCBs (2 ounces copper) for free
(including free p&p) to callers.
Two restrictions I shall make however:
-- only two per caller and
-- only to german adresses as the postage to foreign countries would exceed
the pcb fabricating costs by far.
I hope that Mark Johnson will not disagree with me herein.
I shall wait for PMs.
Greez
SigFire
... for making (amongst other things) this well thought-out PCB available to the public, including publishing the gerbers so that anyone who sees fit to do so can duplicate and distribute them.
I therefore, as a tribute, can offer 14 PCBs (2 ounces copper) for free
(including free p&p) to callers.
Two restrictions I shall make however:
-- only two per caller and
-- only to german adresses as the postage to foreign countries would exceed
the pcb fabricating costs by far.
I hope that Mark Johnson will not disagree with me herein.
I shall wait for PMs.
Greez
SigFire
You mean same power supply but two different devices? Yes of course.
But isn't the USB dac powered by the Raspberry?
If you don't have an analog output from the Raspberry I don't know how much of a difference it will make.
Depending on the power supply and the load on the RPi there might be an issue with the voltage drop across the filter, but a lightly loaded Raspberry work just fine.
Actually, Raspberry Pi2 is still on sale and recommended elsewhere on this forum for having the least amount of electric interference with DAC:s.
@konst: it surprises me as UltraBib is supposed to be ultra low noise already. Without wanting negative criticism (I don't use these ultraBiB so I don't know them) : any good quality DC power supply for audio devices must have very low noise to be called "good". If a linear PSU is not ultra allow noise in a pretty wide bandwidth area it is better checked and when noisy by design it is likely not suitable for high quality audio (with or without veils
True story my friend, I am only going by my ears here, it is subtle but different and preferable in my opinion. I am busy for a few weeks, but will experiment when time frees up.
Two SMPS inline DC filters in series !! Cowabunga !
It's delightful that you're pleased with the resulting sound: congratulations.
I bought it from Amazon- $11.99. I like that the case split in two, so you can set up the components in the lower half with ease.
I can't seem to get a link to work. Here's the item title on Amazon-
Jiuwu- Surface Drawing Split Aluminum Enclosure Project Box Electronic Enclosure Case for PCB 88x38x100mm
I can't seem to get a link to work. Here's the item title on Amazon-
Jiuwu- Surface Drawing Split Aluminum Enclosure Project Box Electronic Enclosure Case for PCB 88x38x100mm
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