There is a wrap around of grounded aluminum around the transformers, and the perf aluminum top and sides. I was not planning on building the case until I had a working DAC, but there was such a long delay in getting the power supply transistors that I got antsy. From other's posts that have their Buffalos initially set up sitting on plywood panels (just open air) the comment has been that not much noise is picked up, so I'm hoping this will be enough. The housing base and back panel are black acrylic for now. When (and if) I get this running, I'll see whatever else needs to be done if noise is an issue. I've done all the normal (tight twisted on AC, keeping AC away from signal, etc.) techniques to keep noise down.
Thanks! I had designed it with something like a birdseye in mind, and when I went to the mill they had some rough lacewood. Until I planed it I couldn't see the pattern, and most was much larger than what I wanted, but there was one corner that was just right. I've got 4 "invisible" LEDs next to the selector switch, that are 1/16 plex rods that will lightpipe back to the rear of the wood.
Now to just figure out this shorting problem, (and I can't imagine not having other issues) and get this up and running. Most of my DIY has been tubes, so this was a real change for me.
75 OHMS! not shorted!!
It occurred to me this afternoon that I was just checking continuity between the S/PDF and GND on the board, and that I should see what the actual resistance is. (DUH!) It measure 75 ohms repeatedly—perhaps this is a correct value.
Does anyone know? I certainly hope this to be the case...
It occurred to me this afternoon that I was just checking continuity between the S/PDF and GND on the board, and that I should see what the actual resistance is. (DUH!) It measure 75 ohms repeatedly—perhaps this is a correct value.
Does anyone know? I certainly hope this to be the case...
Most cases...
do not do much to shield from RF. You really need about 1/2" thick aluminum with no openings (airtight) to get a really good shield… short wavelengths can get through very small openings.
Best is a machined from block case, with an airtight panel screwed on with a lot of machine screws. Of course getting a case like this made will run around $2K or more for a DAC.
do not do much to shield from RF. You really need about 1/2" thick aluminum with no openings (airtight) to get a really good shield… short wavelengths can get through very small openings.
Best is a machined from block case, with an airtight panel screwed on with a lot of machine screws. Of course getting a case like this made will run around $2K or more for a DAC.
internal shield just for Dac/IV?
If one were to build a case like that, how would the openings in the case needed for connectors affect the shielding? It would not be hard to make a small inner box that holds the USB interface, DAC and IV stages; the main difficulty would be the input and output ports, along with the power connectors. So—minimally USB in, 2 XLR outs, and some sort of 8 pin power connector.
Also, I have noticed companies using solid milled billet construction, but have wondered if 1/2 inch plate welded would not work as well. I have access to a CNC mill, but it's a lot of machine time (we're really set up for machining plastics and dense foams). So just machining plates with the correct openings and then welding seems like a more cost effective way for a one-off.
My Pass Aleph is all 1/2 aluminum, but everything is screwed together. I was thinking this was more Nelson building a brick sh*thouse; it's certainly the heaviest preamp I've owned.
Mind you—I'm asking more out of curiosity than seriously considering building one. It was your write up in CA that got me interested in the Buffalo, and your early photographs of the boards out in the open (though since then I've seen plenty of that type of photo) that made me decide to go with a basically unshielded box. With luck I'll have this all hooked up pretty soon and can see what type of noise I get.
If one were to build a case like that, how would the openings in the case needed for connectors affect the shielding? It would not be hard to make a small inner box that holds the USB interface, DAC and IV stages; the main difficulty would be the input and output ports, along with the power connectors. So—minimally USB in, 2 XLR outs, and some sort of 8 pin power connector.
Also, I have noticed companies using solid milled billet construction, but have wondered if 1/2 inch plate welded would not work as well. I have access to a CNC mill, but it's a lot of machine time (we're really set up for machining plastics and dense foams). So just machining plates with the correct openings and then welding seems like a more cost effective way for a one-off.
My Pass Aleph is all 1/2 aluminum, but everything is screwed together. I was thinking this was more Nelson building a brick sh*thouse; it's certainly the heaviest preamp I've owned.
Mind you—I'm asking more out of curiosity than seriously considering building one. It was your write up in CA that got me interested in the Buffalo, and your early photographs of the boards out in the open (though since then I've seen plenty of that type of photo) that made me decide to go with a basically unshielded box. With luck I'll have this all hooked up pretty soon and can see what type of noise I get.
warning: i'm not expert, just amateur with some experience.
ammount of shielding depends on what are you trying to achieve... for normal usage is enough to place it into regular metal case and try to keep tranformers and rectifier diodes on power modules as far as is possible from other components
this distance reduces modulation of multiples of power grid frequency into signal output.
metal box is beside mechanic and safety protection good as a shield for electric fields, generated for example by (unshielded) power cables running around the chasis. but an alluminium foil glued from the inner side of box and grounded will do a very comparable job.
ammount of shielding depends on what are you trying to achieve... for normal usage is enough to place it into regular metal case and try to keep tranformers and rectifier diodes on power modules as far as is possible from other components
this distance reduces modulation of multiples of power grid frequency into signal output.
metal box is beside mechanic and safety protection good as a shield for electric fields, generated for example by (unshielded) power cables running around the chasis. but an alluminium foil glued from the inner side of box and grounded will do a very comparable job.
Hello, I made some measurements with my EMU 0404 and RMAA. I have a problem in the high freqs, and also with noise ... The EMU alone didn't have these issues, so it comes from the DAC or from the WaveIO...
http://imageshack.com/a/img856/2297/m63l.jpg summary
http://imageshack.com/scaled/medium/405/i61k.png thd
http://imageshack.com/scaled/medium/11/m1y3.png swept tones
http://imageshack.com/scaled/medium/62/nj30.png Freq range
What can be the causes?
I plan to change my EI transformers with Nuvotem moulded toroids, change all PSU cables with 20AWG Clairvoyant cables (6N 99.9999% OCC Solid Copper with .50 microns of 24K Gold Plating) +ptfe , and maybe make a little copper shield like the Hifiduino's one for the B2, if I manage to get the place.
Even if I don't really believe in an improvement, I also ordered a USB Supra cable for my WaveIO.
Thanks
http://imageshack.com/a/img856/2297/m63l.jpg summary
http://imageshack.com/scaled/medium/405/i61k.png thd
http://imageshack.com/scaled/medium/11/m1y3.png swept tones
http://imageshack.com/scaled/medium/62/nj30.png Freq range
What can be the causes?
I plan to change my EI transformers with Nuvotem moulded toroids, change all PSU cables with 20AWG Clairvoyant cables (6N 99.9999% OCC Solid Copper with .50 microns of 24K Gold Plating) +ptfe , and maybe make a little copper shield like the Hifiduino's one for the B2, if I manage to get the place.
Even if I don't really believe in an improvement, I also ordered a USB Supra cable for my WaveIO.
Thanks
Miero=> 1) I thought all the B3SE had the latest versions of these regs, no?
2) I measured on the SE output of the Ivy3.
=>Brian, I'm measuring with my RCA, at the output of the Ivy3. This seems a more "realistic" value, of what is injected in my amp, no?
Here is my box http://imageshack.us/a/img839/1613/1nsb.jpg the transfo on the left has gone, replaced by two EI ones, the rest is conform. I have to say that my WaveIO PSU has a Omron 5V relay on its output in order to switch between SPDIF/I2S at the same time. I will put a DPDT switch instead, and change my LM317 PSU for a Placid HD that I've just ordered
In my precedent message, I forgot the most disturbing thing, when I stomp on the floor around my installation, the DAC cut half a second (unlock), then leave again normally. This is very weird, it did not do that before, I thought a loose connection but everything seems OK ... Have you ever seen this?
Cheers
2) I measured on the SE output of the Ivy3.
=>Brian, I'm measuring with my RCA, at the output of the Ivy3. This seems a more "realistic" value, of what is injected in my amp, no?
Here is my box http://imageshack.us/a/img839/1613/1nsb.jpg the transfo on the left has gone, replaced by two EI ones, the rest is conform. I have to say that my WaveIO PSU has a Omron 5V relay on its output in order to switch between SPDIF/I2S at the same time. I will put a DPDT switch instead, and change my LM317 PSU for a Placid HD that I've just ordered
In my precedent message, I forgot the most disturbing thing, when I stomp on the floor around my installation, the DAC cut half a second (unlock), then leave again normally. This is very weird, it did not do that before, I thought a loose connection but everything seems OK ... Have you ever seen this?
Cheers
manudrz: probably not related, but your DC power cables are not twisted and neither cables to LEDs ... try to remove all cabling to LEDs first (might work like antenna) ... and replace them with shielded cables if that is the cause ... also signal cables without metal connector on the chasis might act like antenna
if you have an oscilloscope check the voltage on the AVCC ... or better AC multimeter might detect if there is AC on the output
if you have an oscilloscope check the voltage on the AVCC ... or better AC multimeter might detect if there is AC on the output
yes, might be caused by interference with USB.
manydrz, do you have a thd graph with small or zero signal?
some desktop pc has spdif output on the motherboard, you can try this.
or can you repeat mwasurement with notebook on baterries only? its power adapter might have HF on its output that is spreading via GND everywhere.
manydrz, do you have a thd graph with small or zero signal?
some desktop pc has spdif output on the motherboard, you can try this.
or can you repeat mwasurement with notebook on baterries only? its power adapter might have HF on its output that is spreading via GND everywhere.
Damned, I connected the SPDIF and mass on the same Buffalo pin input... Yes yes throw me small pebbles, you can! On the other hand I still do not have sound with SPDIF, DAC remains "mute" both with my IDE diy drive and with my Sony SCD-XB790 ... I removed the DIP8 firmware and tried again but no change. Any idea?
Last edited:
Ok, I'm remaking my DAC with sealed Nuvotem transformers, the latest DIYinhk Xmos USB interface and a faraday cage for the DAC+IVY3 with steel grid.
Still no solution for my SPDIF input, but I finally won't use it so it's not a problem.
1) I'm wondering if there isn't problem in changing R25-26 (I use SE), I thought about it (for fun). Texas Components Corporation
No problem to use this series (50ppm)? Still 22.1ohms?
2) I also thought to replace the C15 to 20, any advice? Want to test the Cerafine. They have 5mm spacing, but I think it's doable. The main problem is that the 100µF/25V is 16mm high, so I thought take the 16V which is 12.5mm.
Can someone confirm there will be no issue with these 100µF/16V Cerafine caps ? (ELNAC-100) - 100uF 16V Elna Cerafine Electrolytic Capacitor Hifi Collective or, if someone has a better suggestion...
Thanks a lot guys
Still no solution for my SPDIF input, but I finally won't use it so it's not a problem.
1) I'm wondering if there isn't problem in changing R25-26 (I use SE), I thought about it (for fun). Texas Components Corporation
No problem to use this series (50ppm)? Still 22.1ohms?
2) I also thought to replace the C15 to 20, any advice? Want to test the Cerafine. They have 5mm spacing, but I think it's doable. The main problem is that the 100µF/25V is 16mm high, so I thought take the 16V which is 12.5mm.
Can someone confirm there will be no issue with these 100µF/16V Cerafine caps ? (ELNAC-100) - 100uF 16V Elna Cerafine Electrolytic Capacitor Hifi Collective or, if someone has a better suggestion...
Thanks a lot guys
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.