noise
I am certainly no electronics expert but is it not possible we are dragging in noise from the outside world through the mains connection. Most housing units are notoriously noisy. in radio, toroids and filters are used extensively to reduce RFI/EMI. We are either making it or bringing it in. or BOTH. Neither one is OK.
My 2 cents.
Don
I am certainly no electronics expert but is it not possible we are dragging in noise from the outside world through the mains connection. Most housing units are notoriously noisy. in radio, toroids and filters are used extensively to reduce RFI/EMI. We are either making it or bringing it in. or BOTH. Neither one is OK.
My 2 cents.
Don
Hi Salas
I can try to bypass DC blocker and see what is happening… Will report soon...
Hi Ricardo,
For my final note, I’m just coming back every other day and ask myself if to continue that troubleshooting or to take this Khozmo out. I always can use known and tested mechanical attenuator (25k Goldpoint in my case) which gives me my beautiful second DCG3 with crystal-clear sound and very deep noise floor.
Not decided yet if I’m ready to lose $360 for that remote controlled insanely hard to integrate attenuator.
My mains and GND are very contaminaed since I live in very close proximity to Micron Technology Fab. All generated RF and other junk is in my power grid.
I can try to bypass DC blocker and see what is happening… Will report soon...
I assumed that ARTA was picking up noise from above 20kHz when I set measurement limit to 20/20k.
I have both cans build with TRS connector with comon GND. I’ll try advised Earthing.
Hi Ricardo,
Make since to try, but I’m out of permalloy or even Cu now. Might going to try Fe. Let’s see.
For my final note, I’m just coming back every other day and ask myself if to continue that troubleshooting or to take this Khozmo out. I always can use known and tested mechanical attenuator (25k Goldpoint in my case) which gives me my beautiful second DCG3 with crystal-clear sound and very deep noise floor.
Not decided yet if I’m ready to lose $360 for that remote controlled insanely hard to integrate attenuator.
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I used kohzmo pots in one of my builds with total success but mine did not have a remote.... can you disable the remote psu and see the outcome?
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You probably used Khozmo classic mechanical unit with resistors, same concept as I know from goldpoint/elma/dact. My Khozmo is new design micro-relay based. It has no signal trough if power in not connected. External PSU test reviled same noise level. If no power connected to it (means no signal through, but with its own PSU is on and inside of my enclosure), then my DCG3 is crystal-clear. Same clear picture when I install Alps or Goldpoint with Khozmo PSU is on with 500mA dummy load.
Going to create Faraday around IEC.
Hi guys,
I've accidentally reverse volted the right side of the board (the side with the Da Db Dc circuit branch), and i need help with some measurements.
Can someone measure their V+ and V- to ground? I'm only measuring some ~12.5k to ground from V+, whereas on the left side of the board I measure many MOhm to ground from V+.
I'm just not sure what it damaged and I've check everything and replaced all of the bipolars and FETS. But, I'm still getting a huge voltage imbalance when connected to the DCSTB, ~17v on the negative rail and ~11v on the positive. So, a huge imbalance.
Like I said, I think the problem is in the Da-Db branch.
Amazingly, the right side bias is very close, but it's high ~.2v, but all the offset can be easily biased out.
Thanks in advance,
Greg
I've accidentally reverse volted the right side of the board (the side with the Da Db Dc circuit branch), and i need help with some measurements.
Can someone measure their V+ and V- to ground? I'm only measuring some ~12.5k to ground from V+, whereas on the left side of the board I measure many MOhm to ground from V+.
I'm just not sure what it damaged and I've check everything and replaced all of the bipolars and FETS. But, I'm still getting a huge voltage imbalance when connected to the DCSTB, ~17v on the negative rail and ~11v on the positive. So, a huge imbalance.
Like I said, I think the problem is in the Da-Db branch.
Amazingly, the right side bias is very close, but it's high ~.2v, but all the offset can be easily biased out.
Thanks in advance,
Greg
The PSU side powering the relay has Ra//Rb=12.29k i.e. suspiciously close to a 12.5k reading. It can't be showing MegOhm like the other free side. But my DCG3 is installed so lets see if others can practically verify. Over-current possibility must be examined with the DMM in series to the pulled down rail. If normal DCG3 mA consumption is found, maybe there is a sneaky damage done by that reversal mishap to the DCSTB. Q2 is the most vulnerable there.
Salas DCG3 preamp (line & headphone)
Well, beside the fact that my 60Hz spikes are appears only with Khozmo (and not with any of mechanical units that I have in hand) I installed IEC shield. It is GNDed aluminum that I found on one of my old junky industrial controllers. Also, I cleaned all RCAs.
And….damn, I accidentally dropped my test lead prob of GND on one of “-“ outputs on DCST. So, 400mA fuse and BC560 are both “kaput”. I replaced damaged parts and got back to business quickly.
There is absolutely no noise then inputs are shorted and very little 60Hz and its harmo180Hz spikes when I deliver sine with 1VAC RMS -10dB. I found signal ground position that gave me no hum with Audeze. So, I decided to leave it as is and will close box tightly today.
My first salas simplistic RIAA amps has the psu inside the same enclosure as the riaa amp.... I needed to create a screen between the iec inlet and the nearest riaa input rca... A steel plate connected to gnd was effective... later used mumetal with even better results
Well, beside the fact that my 60Hz spikes are appears only with Khozmo (and not with any of mechanical units that I have in hand) I installed IEC shield. It is GNDed aluminum that I found on one of my old junky industrial controllers. Also, I cleaned all RCAs.
And….damn, I accidentally dropped my test lead prob of GND on one of “-“ outputs on DCST. So, 400mA fuse and BC560 are both “kaput”. I replaced damaged parts and got back to business quickly.
There is absolutely no noise then inputs are shorted and very little 60Hz and its harmo180Hz spikes when I deliver sine with 1VAC RMS -10dB. I found signal ground position that gave me no hum with Audeze. So, I decided to leave it as is and will close box tightly today.
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Yes in did, and Ricardo was right. His tip reduced total noise substantially. It was nice to use mu Metal there instead of Al, but I’m totally out of it. Do not understand prices of that Ni alloy either. It must be way cheaper since it is that exotic.
My Arta is calibrated since we discussed it about two years ago. I have 1V RMS on Focusrite input when I see 0dB on Atra screen. I just hope that my Fluke is measure right AC voltage with 1kHz frequency.
My Arta is calibrated since we discussed it about two years ago. I have 1V RMS on Focusrite input when I see 0dB on Atra screen. I just hope that my Fluke is measure right AC voltage with 1kHz frequency.