Hello, first time posting. I am looking for a review of my car audio wiring without a head unit, any help is appreciated,
Motivation: I will be using a WiiM Mini to AirPlay 2 music from my iphone, this connects to my Schiit Modi+ DAC via optical. This is why I have the 2 12v-5v buck converters to power those via USB. DAC->DSP and then to both amps pretty standard from there.
My battery is in my trunk so all runs will be less than 5 feet.
Thanks!
- Streamer: WiiM Mini
- DAC: Schiit Modi+
- DSP: PRV 2.8x
- 4 Channel Amp: Morel MPS 4.400
- Mono Amp; JBL A600
- Fuse Block: amazon link
Motivation: I will be using a WiiM Mini to AirPlay 2 music from my iphone, this connects to my Schiit Modi+ DAC via optical. This is why I have the 2 12v-5v buck converters to power those via USB. DAC->DSP and then to both amps pretty standard from there.
My battery is in my trunk so all runs will be less than 5 feet.
Thanks!
The only thing I'd likely change is going to a 50 amp fuse for the 8g wire in place of the 60 amp but the 60 will be OK.
I'd avoid glass (AGU) fuses in the distribution block).
I'd avoid glass (AGU) fuses in the distribution block).
Hi. If there will be something analog, not digital, power from 5V , i would recommend use not buck converters, but isolated 12/5V converters. With just digital or just optical signals ground loop may not cause any problem, but with analog dac and amplifier with analog input ground may cause problem, noise and such problems, when used in car. Not all amplifiers inputs ground are property isolated from supply ground(12v negative) potential. Using isolated comverters will help overcome this problem and not degrade audio quality. 12v input ground will be no more related to +5v output ground. Buck converter has one common ground.
Thank you Perry. Excuse my poor handing writing but it is actually a 30A fuse going from 8g to fuse block. The entire block will realistically only draw a couple amps. Do you think 30A is okay or bump it up?
Thank you for your reply. It will be Digital -> DAC, Analog from DAC -> DSP. Analog from DSP->Amps. I have not heard of isolated converters but I will look into this.
If your amplifier will have dsp inside and just optical input as example, you wouldn't need to worry about possible ground loop. But if there's dac with analog output, then dsp with analog input, analog out to amplifier analog input - more than one ground loop . Only one drawback is with isolated converters is price . Also it's possible to use one converter with multiple isolated outputs, if such exists with suitable parameters. Do you know exact power requirements of dsp and dac, except supply voltage? They may have external psu rated 5V 2A as example, but in practice draw just 0,5ampere or 1 ampere and there's may no real need to oversize 5v converter. Actually if you have devices near and test connected, measure power draw on +5V with dmm on a 10A range , connected in series with +5V and use supplied ac wall adapter or phone charger etc
8g for the fuse block is overkill. OK but unnecessarily large. You could feed it with 12g fused with a 15 amp fuse, use 3 amp fuses in all slots and eliminate the fuses going to the converters.
That isolated converter looks OK.
That isolated converter looks OK.
This converter looks cheap, but it has transformer, optocoupler for feedback, so it might be ok. Output voltage will be regulated. Qiestion remains, how many mA your devices needs.
What about this? https://recom-power.com/en/rec-s-REM4A.html
Never worked with anything like that but ChatGPT and googling says Modi DAC uses less than .5A at 5v. I can confirm with the company tomorrow. So I could wire that to a usb break out boards is my understanding?
REM4A-1205S looks ok according to it's datasheet. Input 9...18v range covers 12v battery , charged fully reaches 14,4v . You can just solder 2 pcs to veroboard , if pin spacing match.
Ok last question, this one specifically: REM5E-1205S/R8/A
Or that cheap tinysine one https://www.tinyosshop.com/isolated-dc5v
REM5E is expensive ,but tolerates up to 4700uF load capacitance ( we don't know what capacitor have your devices in parallel to dc input ). REM4A mentioned before allows up to 1470uF only . Cheap tiny converter has not all parameters specified , so everything is in question . From photos looks like 2 transistors design ,popular in lowest price phone chargers ,and probably with overrated parameters . Output current 1000ma is probably short time ,not constant load. Also i see small output diode (1A rated), which can be upgraded to bigger one (3 - 5A) ,for improving reliability .Also dual USB output is not helpful ,with any choice you need 2pcs of dc/dc converters .
Also in any case dc filter would be helpful to clean up dc output from hf ripple. You can build it yourself . REM5E specifies output ripple 150mV, i don't know if it can affect audio quality ,but still ,cleaner power is always better .
If you will add output filter, big inductor lets say 100uH 3-5Amp rated (for reduce voltage drop) and capacitor like 1000uF ,ripple will be greatly reduced, and don't care about load capacitance .
Also in any case dc filter would be helpful to clean up dc output from hf ripple. You can build it yourself . REM5E specifies output ripple 150mV, i don't know if it can affect audio quality ,but still ,cleaner power is always better .
If you will add output filter, big inductor lets say 100uH 3-5Amp rated (for reduce voltage drop) and capacitor like 1000uF ,ripple will be greatly reduced, and don't care about load capacitance .
I don't know what a dc filter is to be honest, I am new to this space. I think this product has a filter built in? SD-25A-5
I can also jus try with the REM5E and see how that goes first. Unless you think the SD-25A-5 is a better first try.
I appreciate all your comments very much by the way.
Datasheet for SD-25 converter 5V output specifies low effeciency , just 71 percent, and it can provide much more output power than you need - overkill . Also output ripple specified as 100mV , so just a little better than other small converters.
Don't be scary about dc output filter, just locate inductor for purchase kinda like 100uH 5A for purchase, and capacitor 1000uf 10V .Values are not critical. Even local elecronics parts store can have that.
No , i would not use sd-25 for this project. At best, you should connect dac to 5V power source and measure power draw, to be sure about real power requirements. Do the same for DSP . Then you will easily know , which converter will handle that at best.
Don't be scary about dc output filter, just locate inductor for purchase kinda like 100uH 5A for purchase, and capacitor 1000uf 10V .Values are not critical. Even local elecronics parts store can have that.
No , i would not use sd-25 for this project. At best, you should connect dac to 5V power source and measure power draw, to be sure about real power requirements. Do the same for DSP . Then you will easily know , which converter will handle that at best.
I would get a converter that’s rated at at least twice what is expected for amp load.
I had a similar arrangement a while back and the audio peaks just weren’t a welcome thing for the converter.
I had a similar arrangement a while back and the audio peaks just weren’t a welcome thing for the converter.
Thank you I think I am done looking, I am going to try this one unless someone tells me it's bad idea! MEAN WELL SKM10A-05
2A should be at least double overheard.
Skm10a-05 looks good too , also ripple specified as 50mV , so less noisy output, also allows output voltage trimming to exact voltage you need . Also more effecient at least on datasheet.
You’re welcome, hopefully you’ll not have the experience I had sending a clipped signal to one of my remaining Soundstream D200s.
My fault for not testing adequately…