Tantalums don't have any magic properties. They used to have a size advantage, but aluminum has caught up to some degree. Solid polymer (Oscon) caps have high leakage, but in a PS you don't care. They have excellent performance otherwise and can filter noise better than most. I don't know if they're available in the voltages I'd want.
solid electrolytics (the same ones found on the pc motherboard) have good performance in 100hz/120hz rectification?
There is no doubt that transformers matter: we have already installed bugger transformers on one of our units, and they bring a huge sonic improvement over the stock ones.
Original transformers are:
2x9V, Talema molded (soldered directly on the PCB), 5VA.
2x15V, Talema molded (soldered directly on the PCB), 5VA.
New transformers are:2x9V, Talema toroidal encapsulated, model TRTV302309, 30VA
2x15V, Talema toroidal encapsulated, model TRTV50215, 50VA
both are screwed on the chassis, no longer on the PCB.
I can't explain scientifically, but the sonic improvement is huge.
It seems that you are not convinced by Low ESR caps in this power supply: so I would probably just replace these old VX caps by new ones (not specifically low ESR) like Nichicon KW; we have 2 identical DACs that we work on, the one having the big transformers has already Nichicon KW in this location.
I agree and I have the question in this post: https://www.diyaudio.com/community/threads/2w04-rectifier-bridge-replacement.388537/
But I don't clearly understand the recommendation...
To avoid to mix the subjects, I believe it is more simple to talk about the Bridge rectifier in the specific thread I have started for.
But if I ant to achieve a very good one, I will probably have to build the bridge from single diodes
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Ah, another fact that would help if known from the beginning. Advice given on assumptions could be wrong. This confirms that capacitor charging pulses will be much higher than with the original design. If you are satisfied with the sound of first modified DAC, stick to the capacitors type used.
Reason why DAC sounds better with new transformer, could be in reduced mains noise. It’s possible that new transformer passes less HF noise from mains to the secondary and DACs are known to be sensitive to various noise sources. LM7812/7912 regulators are decent, but far behind currently available solutions. In example, 7812 voltage regulator has only 60 dB PSRR at 5 kHz (noise reduction between input to output of 1000x). Adding snubber will additionally reduce PS noise. You’ll have to read Mark’s article that rayma linked in another thread.
Anyway, that are only assumptions. It is better to take some measurements before and after upgrades, along with the listening tests. That way, correct conclusions can be drawn.
Another way is to change components, with presumably better ones, and listen. However, we can easily fall victims of expectation bias. That’s why I always accompany listening with measurements.
The truth is out there. 🙂
Yes, excellent in all regards. The only place where I'd avoid them is where leakage matters, like coupling caps.