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In Reply to: RE: Linear PSU again: help needed posted by audiodan@tiscali.it on December 09, 2010 at 16:43:59
Hi guys,
Today, just hours ago i made huge step forward in my cMP set up.
Ones again -power supply ! I use low profile computer case and have not enough
space for everething i want to put in , so in time my MoBo died, i change design. Cut off some bottom part of a case to provide access to back side of MoBo.
First, i follow JackWrong way , but just install small electrolit cap on open part of MoBo and move some of my caps on back of moBo . It was posible use short wire 30-35 mm longfor big caps.
Difficalt to say about improvment , becouse I start to use Buffalo DAC and tube Buffer, belived it was also on part of cMP.
Access to back of Mobo ,give me ability to mesure by my basic PC Oscilloscope what
i got . I find difference 2-3 fold in mvolt on deferent end of 35mm wire.
So , using strip of PCB board as a wire (should be square size or so, but not narrow)
I connect my caps to Mobo.
Result- excellent. Sound more clean, bass more controlled,mach better resolution on low level. I still not mesured what I got by Oscilloscope, planned make same approch
for CPU +12volt and added small NOS cap all around, will see what happen.
Gene.
Follow Ups:
Hi Gene!
It's interesting but photo is small and dark :(
http://cmp2-mihaylov.narod.ru/
will be sent tommorow better, this ones just scaled.
Hi guys,
I starting use PIO caps for fitering with great result. Two 2mf PIO caps reduce
noise on 10 db from 10 khz upward , on 5 volt MoBo line, but still some spike.
Sound has changed , more space , cleaner,more impact ,distant instruments and low level signal sound more smooth ,refined.
More experiment on a way , will report.
Gene.
Hi guys,
Continue install PIO caps for filtration on P24 connected by PCB . Again , success .
Noise level drop on 7-9 db according to oscilloscope reading ( +12 MoBo).For +3v MoBo and +5v MoBo added small caps 0.001mf -improvment on 3-4 db,( it is giong to measurement limit of my oscilloscope -90- 95db.).
Sound cleaner, more space. More caps on a way.
I think this is a way forward. Salas shunt regulator splited on two units, last one should
be installed closely to board. Buffalo DAC use also smallest shunt reg., whith connectors
pin just a 1/2 inch long.
Picture show last addition.
Gene.
BTW. How post bigger picture?
"BTW. How post bigger picture?" - In no way unfortunately :( ("All images over 640x480 resolution will be scaled accordingly to reduce bandwidth and storage space."). It is possible to upload here http://imageshack.us/ (for example)
http://cmp2-mihaylov.narod.ru/
Hi guys,
I installed PIO caps on +12 volt CPU line, ( two 6mf caps) but no any good result this time , even added another 47 mf non-polarised cap , not make improvement. Just for experiment I connected my 45 Amp lead battery by short, 150 mm 8 AWG wire to 60 mm long strip of PCB wich is soldered to MoBo- nothing changed. Only option I see now -replace switching regulators. First I am going to try with memory, as JackWrong
did, but will use LT1083 regulator, feeding from original 5 volt spot.
Memory 1.85 volt spot, I find on MoBo ( maybe it is not memory spot ?) very noisy -same as CPU , you can see on picture .
For 3.3 volt MoBo I added two 6mf PIO caps , this give me litlle bit improvement .
Level of a noise same by analyzer , but reading in mv better ( 1.6 mv vs. 3.0mv).
Adding 47 mf non-polarised cap reduced noise just on -2db. Sound- wise I cant see any difference.
Gene.
Jack is not Wrong but Wong ;)
http://cmp2-mihaylov.narod.ru/
Thanks Mihaylov, sorry Jack !
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