After reading some previous post, I have tried to stack 2 x 1541 together onto my Arcam Black Box. As a result, the dynamic seems to improve. But I got some unwanted background noise (SA...sAS...sAS) when the music starts to play. When there is no music, no Sa...SAS. In that case, I belive that the chips are still functioning otherwise I will always get these noise. Could it be the two 1541 interfering with each other or I have missed somthing here. I have also checked the power supply to the DAC and it looks to be fine. Any comments. TIA.
Did you CD player sound louder after the stacking?
Yes, it does but It also give you more punch, Sound is more forward ...etc but unfortunely, I got this noise problem.
So no sign of a cure for your noise problem yet? What value of R are you using for passive IV conversion? If it is 100 ohms, you shoudl probably half it or use even less than 50 ohms.
How does teh paralleled DAC sound and did you simplybsolder teh one on top of teh other.
Also what Power supply are you using? If TL431, I presume you should half teh value of the series resistor since current draw is presumably double.
Let us know how you progress.
I was using 50 ohms in the first place. I use LT323 which is a 3 amp 5 v regulators. The piggy back chips do get quite hot. Also the SAA7220 also get hot when using piggy back.
Since the original DAC is working fine, I do not want to raise the risk by changing too many parts of the DAC.
(maybe I can try a 30 ohms resistors). Any further suggestions.
Make sure the I/V stage is not overloaded with double output current and increase the active divider oscillator and bypass capacitors twice. May be it can help. May be it can't and you'll have to use separate capacitors for each chip.
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