LT1083 7.5A regulator are a bit overkill, maybe 1086 more realistic. But i prefer 723 with PNP BJT over 78xx or even 317
As power supplies for TDA1545A, I've tried a few. TL431 shunt, BJT-assisted TL431 (lower Z-out) and TL431 as Vref feeding an EF. I prefer this last one (the shunts improved a lot with lots of electrolytics on them) but I'm not yet done with PSUs.... A normal 3pin reg feeding a single TDA1545 is going to have highish Zout due to the very low current demand (3mA or so).
I was using about 2,200uF as decoupling for pin7, same resistor values as in the DS. I figure passive filters do the best job of noise reduction.
I was using RCR where Rs were about 15-22k (can't recall exactly) and C was 2200uF. VDD to first resistor of RCR chain, pin7 to the second one.
When I had the BJT assisted shunt, I put 20,000uF on its output and this improved the bass rather a lot. Trouble is - 20,000uF is rather bulky!
More capacitance always sounds better to me, overkill or not. Currently my DAC has close to half a farad of decoupling (on the active stages, about 20,000uF on the DAC chips) and the bass sounds truly awesomeMy amp hasn't caught up yet though, still has only about 50,000uF....
Long overdue for upgrading. Good job caps are cheap here
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I parallel up lots of small caps, have tried using a big single one (68,000uF) but didn't sound as good. Here I get 3,300uF/10V and solder them up 40-50 to a board in parallel. So one board is over 0.1F. Takes a while to power up with this much uF but the wait is worth it![]()
Yes, this huge quantity of caps won't fit on the boards. For my DAC I've built 4 100,000uF PCBs which I have used as the 'feet' for the analog PCB. They can be mounted underneath by a few cm of thickish wire (say 20AWG). I only use these caps to decouple LF, the HF is handled by a big stack of 1206 22uF ceramics on the chips themselves.
When the caps are on the output of a reg, the ripple current is negligible and low ESR isn't a requirement as there are so many in parallel that the wiring begins to dominate over the internal resistance of the caps. Hence Panasonic FC are definitely overkill in this application - use very cheap 'lytics where the ESR isn't disclosed
I shall be interested to learn if you hear a difference - for me it improves the soundstage at LF, so I get more of the original acoustic coming through. Also rhythm is enhanced, more likelihood of foot tapping....