before i go down the workshop and punch out the casework on my friends turret punch can anybody see any potential problems with the layout below?
bottom tray:
Thanks
bottom tray:
An externally hosted image should be here but it was not working when we last tested it.
Thanks
I suppose the two small PCBs are rectifier bridges+capacitors, right?
Why don't you try to put any of them closer to corresponding amplifier PCB?
What is the white area in the upper right corner? Is it reserved for something?
What is the white rectangle between toroidals? Can you try to put there rectifier boards instead?
Regards
Why don't you try to put any of them closer to corresponding amplifier PCB?
What is the white area in the upper right corner? Is it reserved for something?
What is the white rectangle between toroidals? Can you try to put there rectifier boards instead?
Regards
@Bibio, may I ask if you are using a Raspberry Pi i2s dac mounted on the Pi, and placed inside this same case?
Your concerns may be warranted since I'm potentially seeing a big ground loop there, which needless to say, is an invitation for magnetic coupling. Your left and right audio grounds are inevitably going to be joined at both the RPi (with a DAC board, I guess?) and the headphone jack, while being split up on two amplifier boards in between. You will need to interrupt said ground loop somewhere on the amplifier boards, and if it involves just a 10 ohm resistor or so. Other than that, it looks OK - orient the transformer end with the wiring coming out away from the electronics in the final thing.
TBH, going dual mono in a headphone amplifier has zero benefits and a number of drawbacks. It only ever makes any sense for a balanced headphone amp, balanced headphones featuring nicely separated signal returns.
TBH, going dual mono in a headphone amplifier has zero benefits and a number of drawbacks. It only ever makes any sense for a balanced headphone amp, balanced headphones featuring nicely separated signal returns.
yes, at the moment i'm using an iqaudio dac+ but i'm thinking of swapping it out for the hifiberry dac+ pro. i remove the phono sockets and wire direct to the headphone boards.
yup i already have a ground loop on my test bed but its a weird one, there is a bad hum until i start to play music at which stage the RPi DAC somehow removes it and will continue until i cold boot the RPI again. upon first turn on of the system there is a HUMMMM then when i start to play music its an inky black silence.
the dual trafos is what Richard recommends for his Sapphire headphone amp.
I see that the dac+ pro has two clocks. I also have some iQaudio dacs, as well as some Audiophonics dacs. The latest audiophonics use saber es9023 with tcxo clocks.
I'll be following your posts on your combination Sapphire/Pi/dac setup.
Very interesting to me.
That probably means that once turned on, the output amplifier of the DAC will remain active, providing a low source impedance. Getting a hum when the output is essentially open circuit is nothing too unexpected and not necessarily an indication of a ground loop, but possibly of insufficient shielding.
hhhmmm, thats interesting but also disturbing.
i have a dedicated mains line from my consumer unit that powers my audio/multimedia system in my living room. i had this and extra sockets installed when i moved in about 20 years ago and recently i had my consumer unit replaced.
well today i decided that i would try my pifi on another spur in the house (kitchen) and to my surprise when i turned the headphone amp on without the RPi being plugged in i was greeted with silence, not a bit of hum to be heard where before it would hum like a good one. i then turned the RPi on and i now get a buzz instead of a hum so i can put that down to the wall wart that powers my regulator that powers the RPi.
am i happy? hell yes but i'm also disturbed as i now have to track down why i'm getting a bad hum from the mains in my livingroom.
i have a dedicated mains line from my consumer unit that powers my audio/multimedia system in my living room. i had this and extra sockets installed when i moved in about 20 years ago and recently i had my consumer unit replaced.
well today i decided that i would try my pifi on another spur in the house (kitchen) and to my surprise when i turned the headphone amp on without the RPi being plugged in i was greeted with silence, not a bit of hum to be heard where before it would hum like a good one. i then turned the RPi on and i now get a buzz instead of a hum so i can put that down to the wall wart that powers my regulator that powers the RPi.
am i happy? hell yes but i'm also disturbed as i now have to track down why i'm getting a bad hum from the mains in my livingroom.
I'd guess phase and neutral in the outlet are reversed - and in terms of electrical fields at the xfmr, that absolutely matters. Could you check that?
Here in polarity-non-observing power plug land, it would not be too uncommon for "high-enders" to "phase out" their equipment, i.e. turn power plugs to minimize hum. IMHO it is more of an indication of bad construction on part of the gear if it makes any (audible) difference, but I digress. A good xmfr would have a shield winding to minimize primary/secondary capacitive coupling (goes to secondary-side ground), and maybe general shielding of primary-side E field as well.
Here in polarity-non-observing power plug land, it would not be too uncommon for "high-enders" to "phase out" their equipment, i.e. turn power plugs to minimize hum. IMHO it is more of an indication of bad construction on part of the gear if it makes any (audible) difference, but I digress. A good xmfr would have a shield winding to minimize primary/secondary capacitive coupling (goes to secondary-side ground), and maybe general shielding of primary-side E field as well.
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sockets were tested by electrician last year when the new consumer unit (fuse box) was installed. the xfmr i use is a troidy.pl audio grade one that i had built about 2 years ago single 300va with 4x 12v outs, i'll be swapping that out at some point for the two new ones in picture in first post when i get the case built. as another little test i run an extension cable to another different socket and plugged the RPi into that and the buzz dropped even more so i'm guessing its the wall wart for the RPi that is giving me the problems.
i had a listen too some of my favourite tracks and my jaw nearly hit the floor, i thought it sounded good before but now it sounds sooo much better and cleaner.
i think i have decided to use full 430mm sized case instead of making things crowded.
i'll take the wall sockets off sometime next week and see if anything is loose on the backs.
i had a listen too some of my favourite tracks and my jaw nearly hit the floor, i thought it sounded good before but now it sounds sooo much better and cleaner.
i think i have decided to use full 430mm sized case instead of making things crowded.
i'll take the wall sockets off sometime next week and see if anything is loose on the backs.
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