L-Adapter

[triode_al]

Salas what a lot of low & mid information lost with SMPS.

How universal is this remark? I use such a ‘filter’ in my 2SK182 after the Meanwell. It sound good.

 

[merlin el mago]

With the Mark Johnson PO89ZB SMPS DC inline DC the SQ improved a lot same noise but tone more low so disturb less.

 

[merlin el mago]

How universal is this remark? I use such a ‘filter’ in my 2SK182 after the Meanwell. It sound good.

This info is related for comparison between a SMPS + Mark Johnson PO89ZB SMPS DC inline DC vs L-Adapter and in my audio system.

 

[merlin el mago]

The noise seems like when you phone and it's busy this kind of noise is only playing music, without music hiss like white noise.

Both kind of noises it's only in right channel like with the SMPS.

When upsampling to DSD it's more strong so surely laptop polluting the sound.

 

[merlin el mago]

Salas SMPS + filter 0 noise playing natives DSD files also 0 noise upsampling PCM files to DSD256 I guess both thanks to the DC filter installed between de noDac PSU & BiB, now two DC filters: one for the SMPS & the other PSU-BiB. So I'm sure the noise is L-Adapter related.

 

[Salas]

How's the grounding of your L-A done to its chassis and mains ground? Maybe needing another approach for your application.

 

[merlin el mago]

Very good questions, tomorrow I let you know, thanks.

 

[merlin el mago]

A picture is worth a thousand words.

 

[Salas]

Maybe the laptop prefers floating because its normally a battery operated device. When on SMPS recharging mode we don't know if the DC output is referred to mains either. In general try NTC thermistor for mains earth to chassis and/or the L-A's DC out zero should be tied to its chassis.

 

[Salas]

*Since your L-Adapter's DC output reads good and AC ripple reads zero or little on the DMM even when seriously loaded, there's nothing wrong with your build. Everything else is about system integration.

 

[merlin el mago]

Maybe the laptop prefers floating because its normally a battery operated device. When on SMPS recharging mode we don't know if the DC output is referred to mains either. In general try NTC thermistor for mains earth to chassis and/or the L-A's DC out zero should be tied to its chassis.

Could be better to connect 1st mains cap negative to chassis?

 

[Salas]

Its an option.

 

[merlin el mago]

OK 1st will try 0V output to chassis.

 

[merlin el mago]

What NTC thermistor value?

 

[Salas]

Hmm... some inrush current limiter disk around 33Ω 1.3Α. No bigger than 1.6A-2A 20Ω given what your 120W transformer can provide during at hard fault to earth.

 

[merlin el mago]

How do you calculate the value? I ask to use it for other projects, TIA.

 

[Salas]

In this case I thought gο hot less resistive at no more fault current than the range of SLB fuse for the specific transformer. ICL NTC datasheets have R25 spec (resistance at 25C) and Imax spec listed.

 

[merlin el mago]

Local store don't have stock of 33 ohms but have 22 ohms, could I use it?

 

[Salas]

Looks like it was popular the 33. Yes use a 22.

 

[merlin el mago]

Without the NTC but mains earth connected togheter with r-core shield & 0Vout to chassis still the same noise