I do have a DAC-1 too and it did not buzz on DCB1. Description reminds a mains ground loop but you said you got DCB1 PCB ground lifted with yin yang diodes?
It could be a malfunction in that DAC then? Check DC offset on it as written before.
DCB1 ground is not lifted -- it floats.
The ground POST that connects the TT ground line is lifted.
Should I put yin/yang diodes in the DCB1 from power supply common to earth ground as well? I did not know what to do about this.
It does not sound like a ground loop. Just very noisy hash at a higher frequency.
The ground POST that connects the TT ground line is lifted.
Should I put yin/yang diodes in the DCB1 from power supply common to earth ground as well? I did not know what to do about this.
It does not sound like a ground loop. Just very noisy hash at a higher frequency.
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If you got diodes between the DCB1 PCB GND and some earth return wire to chassis, its considered lifted due to the diodes are not conducting at all until something bad happens and breaks the 0.6V limit. Then it gets grounded to channel the fault current. Floating would be if it had some resistor like 10R across those diodes.
Mains earth ground is supposed to go only to chassis when the DCB1 PCB ground has the yin yang diodes or a diodes bridge in between. See some Pass DIY amps and preamps they have wiring shown for such to picture it better.
Mains earth ground is supposed to go only to chassis when the DCB1 PCB ground has the yin yang diodes or a diodes bridge in between. See some Pass DIY amps and preamps they have wiring shown for such to picture it better.
The DCB1 PCB ground is the center tap of transformer, correct? I have nothing between that point and the chassis. I have mains earth to the chassis, and the yin yang diodes between chassis and the phono ground wire.
At centre tap and at 0 at a PSU test points /extra connector place after the regs.
Your TT ground lug has no electrical relation to mains earth or DCB1 then if its insulated with a plastic collar. Has no function when there is no fault current conducted to it from the phono.
Put an MKP or so in between and see if it disappears. If not, look for ground loops. That sound discription is more oscillations then 50/100 Hz loops to me.
Weird....
There are two independent chassis for the phono section -- one per channel. Their center taps are connected together through speaker post style ground lugs. These are isolated from the the chassis.
The TT ground wire is connectd to one of these lugs. When I touch the tonearm, there is a mild hum.
Yin/yang diodes are connected between earth ground of the DCB1 and to an isolated ground lug on the DCB1 chassis. When connecting the phono section ground lugs to this ground lug, I can touch the tonearm and there is no hum.
It sounds like I should be connecting yin/yang diodes between the CT of each phono section and earth ground. Then no connection between the Phono section and the DCB1 is necessary.
Also, I should be connecting the DCB1 PCB ground via yin/yang diodes to it's earth ground. The external ground post on the DCB1 is not needed.
Will do that tonight and report back.
If that is true, then yin/yang diodes are a great grounding method for both sound and safety.
It "should" work on the phono section, and putting it on the DCB1 should stop the DAC noise.
That would be perfect.
It "should" work on the phono section, and putting it on the DCB1 should stop the DAC noise.
That would be perfect.
The yin-yang only raises your gnd potential, nothing else. It makes small loops big. You shall only have one signal devise directly coupled to ground. All the chassies should be directly coupled to ground. This answer was directly intended for AndrewT.
So, I took a wire from the PCB ground near the buffer, and wired it to the yin/yang diodes that were connected to the earth ground. Now, when I touch the phono headshell without connecting the phono ground wire to the DCB1, there is NO sound...
EXCELLENT!!
Sometimes I see equipment with chassis/earth connected lugs... what are they for?
EXCELLENT!!
Sometimes I see equipment with chassis/earth connected lugs... what are they for?
I think a CL60 would also be appropriate to parallel, just in case fault currents knock out the diodes.
BTW: The DAC appears broken.... with nothing plugged in, it shows 10 mv VAC -- I did not bother checking the frequency.
No problem with the DCB1.
No problem with the DCB1.
So you essentially follow the diagram on top of this page now, just without a 10R, yes?
They are auxiliary chassis at mains earth potential lugs in case of noises occur with unknown new equipment introduced in a system to try solve. They are not too common these days.