I already though about pot shielding. I’ll go and cut metal tube (like a cylinder) to inclose pot inside of it. Not sure if to use Fe, Mu Metal or Cu... Cu is the easiest material to work with, but not sure if it better than the rest of materials to block EMI/RF.
One thing at a time so to find the weak point of low level spikes Lch ingress when the lid is closing in. To learn something for the future. Start with signal cables routing. Even the mains cables to the front switch could run lower. Everything shield see it to have continuity with the chassis also.
Just fired mine back up after a long job of putting it all in a nice chassis. First time with the I select board. I have taken power from one of the big caps on the DCSTB. On power up the led block for the rail that I took power off wasnt lit.
Basically the I select is shorting that rail. I noticed the 7812 was getting warm. It seems to be isolated from its heatsink correctly.
Any hints to what to look for.? I measure 49ohms across the dc input terminals..
Thankyou
Basically the I select is shorting that rail. I noticed the 7812 was getting warm. It seems to be isolated from its heatsink correctly.
Any hints to what to look for.? I measure 49ohms across the dc input terminals..
Thankyou
So, I made advised arrangement and replaced all wires with coax (also for the headphone output). All cables moved down and secured on my bottom plate. Tried to locate them as far as possible from DCSTB. So, I placed them under DCG PCB and routed from there through.
Now, these previously observed spikes when down and all noise include these specs got lowered significantly when I closed top LID. Stunning results and please see attachments. I'll set listening session tomorrow. Salas, thank you a lot for learning curve.
Attachments
Congratulations for debugging the low level grunge details in your build.
RightMark upgraded its general performance assessment from very good to excellent now.
By the way IMD-SMPTE which is much more intruding than any alike levels of THD and can confuse sonic results in complex dynamic music is pleasing to be reported as especially clean as in those results.
ARTA shows very low level noise floor and really rudimentary grass spikes on both channels with lid on now. Very good picture for an SE diy build with mains in the box. This is professional gear noise floor territory. Difficult to know what contributions are DCG3's and what are measurement loop's noises and distortions when so down low.
Although the ARTA THD+N numbers are highish they are different to the much more likely ~0.003% RM numbers. Even when RM measured at a 3dB higher test tone. 192kHz Fs in ARTA isn't helping it seems, could be integrating the usual high band noise (30kHz-96kHz) from interfaces like this Focusrite. There is also a difference in third harmonic spike level on the right channel not repeated in the RM charts. Better to be using same one interface channel if it proves a trait with dual channel ARTA charts. Its good you used two different programs so we could compare some areas.
Anyways, besides on how to repeatedly measure with home studio interfaces across measurement software platforms when optimizing levels and settings or software drivers which would a big discussion on its own right, the improvement in your case using the same gear and methods is well established.
I would also hope you could hear a bit of better clarity now than before but not easy. Although you averagely made 15dB improvement on grunge spikes in left channel with lid on, the ear can't discern such things directly. Like a -105dB lowish frequency spike going -120dB. There could possibly be a small side effect in fine resolution gains though since the circuit itself got rid of some imbalanced nuisances.
RightMark upgraded its general performance assessment from very good to excellent now.
By the way IMD-SMPTE which is much more intruding than any alike levels of THD and can confuse sonic results in complex dynamic music is pleasing to be reported as especially clean as in those results.
ARTA shows very low level noise floor and really rudimentary grass spikes on both channels with lid on now. Very good picture for an SE diy build with mains in the box. This is professional gear noise floor territory. Difficult to know what contributions are DCG3's and what are measurement loop's noises and distortions when so down low.
Although the ARTA THD+N numbers are highish they are different to the much more likely ~0.003% RM numbers. Even when RM measured at a 3dB higher test tone. 192kHz Fs in ARTA isn't helping it seems, could be integrating the usual high band noise (30kHz-96kHz) from interfaces like this Focusrite. There is also a difference in third harmonic spike level on the right channel not repeated in the RM charts. Better to be using same one interface channel if it proves a trait with dual channel ARTA charts. Its good you used two different programs so we could compare some areas.
Anyways, besides on how to repeatedly measure with home studio interfaces across measurement software platforms when optimizing levels and settings or software drivers which would a big discussion on its own right, the improvement in your case using the same gear and methods is well established.
I would also hope you could hear a bit of better clarity now than before but not easy. Although you averagely made 15dB improvement on grunge spikes in left channel with lid on, the ear can't discern such things directly. Like a -105dB lowish frequency spike going -120dB. There could possibly be a small side effect in fine resolution gains though since the circuit itself got rid of some imbalanced nuisances.
Yay....I have music playing sweetly through the final implementation. Took some debugging for this beginner!
So I had the polarity of the power to the I select wrong for some reason. And it was twice the voltage I expected. Currently the I select is powered from an lm317 but I shall repopultat the psu stage of I select.
I had tonnes of noise and hum with the new chassis. And my selector wasnt working. I had the centre ground pin of the selector switch on the wrong pole.
I added grounds from volume pot to signal ground. Also a ground to what I think is a star ground from the IEC. The DCG3 also grounds to this.
Such simple things make so much difference.
Just got to add a lid.
Playing music from my Rpi mega stack. Sounds wonderful. Soundstage and depth has opened up and the LF has gained weight....in a good way obviously.
Thanks for all the guidance
So I had the polarity of the power to the I select wrong for some reason. And it was twice the voltage I expected. Currently the I select is powered from an lm317 but I shall repopultat the psu stage of I select.
I had tonnes of noise and hum with the new chassis. And my selector wasnt working. I had the centre ground pin of the selector switch on the wrong pole.
I added grounds from volume pot to signal ground. Also a ground to what I think is a star ground from the IEC. The DCG3 also grounds to this.
Such simple things make so much difference.
Just got to add a lid.
Playing music from my Rpi mega stack. Sounds wonderful. Soundstage and depth has opened up and the LF has gained weight....in a good way obviously.
Thanks for all the guidance
Attachments
Like Salas has pointed out, I am puzzled by the H2/H3 profile differences of the L from the R channels, especially since the THD and THD+N numbers are identical.
Were the measurements taken when hot? Perhaps I missed this but at what input and output voltages were the plots done.
Thanks. nash
Salas thankyou for your continued support on this thread. Especially for beginners like me it is a big commitment into your time to look after us.
Best regards
James