Updates on My Systems TDA-1305 DAC SMPS

Click pics to enlarge. Top, Sansui F55 flanked by Beydas. On Center Shelf of Rack is the FU-50 amp. Lower rack the APPLause 300B amp. On top of rack a pair of 新时 597 Resonators.

Letter from Shenzhen (23-12): Updates on My Systems

Current Trajectory: Sonic Sleuthing - Struggles, Trials and Errors

Most readers of this blog arrive via a Google Search. Of these, a number have become regular readers, and they of course are of most interest to me, like family, They identify with our approach and values. Not only that, a sub-fraction believe the devil is in the details (indeed) and sometimes, like family, scrutinize every word (I can tell from some of the comments) or even pic. Sometimes I cover my journey in great detail, which I know is of no use to most people, but I think interesting to these readers who like to mine the fine lines. So, it's time to inform you of some of the changes here in my system. In the most important ways, configuration and most gear have stayed more or less the same as in my Mid-Trajectory article (if you look at the pic of system then, it's not so different from now, top pic)

Sonic Woes

Before I left on my trip to NYC (and UK) in mid-June, as is my wont, I made sure I turned off everything in my system(s) in Shenzhen. When I came back in early September, the system sounded foggy and sluggish. I was quite surprised but thought it was just wake-up woes.

It was not that simple. After some time it started to really bother me. Now, in NYC, on much more expensive and better gear, I exclusively listened to real albums, on CDs and LPs. Hence, some friends teased that I'd not be able to go back to streaming! But I knew my systems well, and was sure that was not the cause.

Now, ever since the Beydas "Stirling" LS3/5a's (here and here) arrived in mid 2022 I had been listening to them. In my reviews I used them as a reference, even if they were not the last words in anything. In real life, if a certain acceptable level of fidelity and musicality is achieved, lazy I would be the last one to tinker with the system. And so it had gone on for almost a year. Although I rotated the 15 and 11 ohms, I listened more to the latter.

Why the deterioration now? I had NO clue! I swapped preamps, changed rectifiers etc - still no clue. Finally I swapped out the bi-wire Belden "1609", which I know to be on the soft side. I tried out the several pairs of freebies that came with the loudspeakers. The "Audioquest CinemaQuest" (as believable as "Stirling" or "Belden") improved things a little but, still, I could not get back my previous sound.

Sansui F55 Redux

Finally, unable to stand it, I swapped out the Beydas/"Stirling" and went back to my Shenzhen longtime workhorse Sansui F55 (See Top pic; Basic Info from a long time ago here). Cables still the "Belden 1609". Wow, the difference was not subtle at all. I got back all the air, treble sparkle, and had a much better bottom end. Agile and lithe, the sound was wonderfully familiar. I know actually very well the difference between the Sansui and the Beydas. Although I have always preferred the greater bandwidth and power of the Sansui, I stuck with the LS3/5As for a long time as a review tool. They are good enough to tell me the difference between gear and were voiced more similar to something most readers are familiar with. I also know the Sansui's are much easier to drive. Previously my Aosibao 6P1 PP amp (now with a problem in 1 channel) drove the F55s much better than the LS35s. And this is also true now for my BRZ FU-50 Amp too. Whereas with the 35, it'd struggle during loud passages, with the Sansui it shows no strain whatsoever. Here, I'd like to clarify that although I use the FU-50 amp as a workhorse I actually prefer the more powerful APPLause 300B. The latter used to have socket problem (pops) that irked me so I did not rely on it. But recently after reworking the sockets and tubes (just by inserting and pulling the tubes repeatedly), the problem went away. But I had already been accustomed to the highly reliable FU-50. It's a bit like the Sansui vs LS3/5a, and shows you, again, that for me, as long as it's within acceptable range, for listening to music I can easily adjust. The system now is so good that I actually rolled in the 80 Rectifier in the FU-50 amp. The 80 is more yin than yang, but a subtlety champ, and the sunlit Sansui can now afford it. Marvelous!

Although the system put the smile back on my face, or cleaned up my ears, that was not the end of the story! No.

UMI on top of the TDA-1305 DAC.

Enter the UMI and Second Try for Beydas Very recently, I got a 2nd gen unit of UMI 1:1 Transformer to review (Our writer ELO waxed lyrics about an earlier version very recently here). I placed it between the DAC and Preamp, and plan to write about it in a dedicated article. For now, let's just say it brought even more air into the already well ventilated Sansui system, which I happily wallowed in. With all that happening, I thought, why not give the Beydas another chance? Well, yes, I swapped back the Beydas. And? Well, slight improvement but still no go. Still lacked energy. No go.

Freak Event: The Power Supply Musical Chair

The 2nd gen UMI has an unusual feature, a 5V DC power is required to operate the XLR connection relay switch. RCA can do without, but I was advised that even then plugging an LPS 5V improves the sound nonetheless. So, I scrambled for testing this. My 1-bit TDA1305 DAC has for the longest time been powered by the BRZ (伟良) 5V LPS. Here are my various Power Supplies. As you can read from the link, I had from the start some reservations about the BRZ LPS. Even then, I connected the BRZ 5V LPS to the UMI and instead powered the DAC by my unused Wanptek SMPS. Guess what? I was SHOCKED that the sound improved markedly. NOT through the UMI being powered (the effect is subtle, as evidenced by removing the BRZ 5V). BUT the DAC as powered by the SMPS became a MUCH better beast! In fact, it exceeded all my expectations! In fact, later I tried the DAC's generic stock SMPS, a tiny thing, and it was still significantly better than the BRZ. Convinced that the DAC is now in full glory, I tried yet again to get my old sound back!

Wait! There's more! A condensed version: I took the UMI and my BRZ LPS to my JBL friend and tested them there (he uses XLR, mandating use of the 5V DC). As I expected, the UMI did a spectacular job all around. BUT, the revelation was that at his place the BRZ 5V LPS underperformed the generic cellphone charger my friend has. You figure! The BRZ dulled and blunted the sound.

Beydas Redux

Thus equipped, convinced by the newfound energy of my DAC, I once again switched back to the Beydas. Well, well! While I'm not sure I got all my old sound back, I'm sure finally I got much of it back. The sound was still perhaps a bit dark, but not unnaturally so. I then did further adjustments, reverting to using the crisper 5R4 rectifiers for the FU-50 amp, and removing the grills of the Beydas, and the sound improved a little more. All with the same "Belden 1609".  I also switched back to the APPLause 300B and the sound gained much power and solidity, as expected. I was very pleased, and the experimentalist in me pushed on (even if I know the Sansui is ultimately even better for these flea-powered amps). As I write I'm still listening on the Beydas.

新时 597 Finally, I experimented with positioning of these incredible voodoo devices, on which I have not written much. Supposedly they work best upon a vibrating platform, like on a loudspeaker. I positioned them atop the Beydas and it was very good. Then I tried putting them on top of my equipment rack (as in top photo) and it was even better! Much more solid center imaging and energy. The way to play with this thing is endless!

One thing I suspect, but cannot confirm now yet, is that I brought back to NYC 4 pairs, and for 2 months here in Shenzhen prior to my departure I had 5 pairs running in my room. I suspect they energized the room so much that I was spoiled. For my money, using them in the center, away from loudspeaker surfaces, is just as effective, surprisingly! I suspect, for this unique device, the more the merrier. My NYC friends Andy and Kevin all have only praise for this thing! There's an article to come at some time...

Comments Finally, after quite a struggle, my Beydas LS3/5As have become quite listenable again (though perhaps still not quite back to their old days in my aural memory). I'm still not at all sure of all the reasons why! Read the above and draw your own conclusions. Here are my observations and what I think:

• All LS3/5a's, real or replicas, are not that efficient. With higher power (say, a PP amp, or a classic UK integrated) one can get more control and open up the sound. But people like me also like to run them with low powered SET amps, in which case you would have to do a lot of adjustments to get good results - setup skills are required. My Sansui is easier for my amps, especially the FU-50 (over-spec'ed; I estimate around 5 watts whereas the 300B amp sounds like 8 watts).

• LPS vs SMPS "Traditional" wisdoms are for the birds. Time and again for me, SMPS outperforms LPS. SMPS is more agile, lithe and alert, whereas LPS tends to be heavy and solid, but to each his own. Keep in mind, many of the world's most high-end brands, like many Swiss brands (as in my Nagra PL-P, also Soulution etc), embrace SMPS. Populist ones, like Schiit, does too! In my case, the BRZ LPS really does not measure up to my mass market (and cheap) SMPSs. One possible explanation for my woes is that the BRZ LPS has somehow deteriorated over time and gotten worse (caps? but it hasn't been that long...).

• 
  TDA-1305 DAC (https://m.tb.cn/h.5QVYLVp) Although I mentioned this DAC a couple of times before I never really wrote about it. Aside from the Meridian Explorer I used before it, I don't have another one. It has served me very very well for almost 3 years! The Meridian is a little more rhythmic, but this thing is better in almost all other aspects. The thing is around 200 RMB (under 30 USD) and doesn't even have a brand name (the TB link shows the maker)! The USB Input is Default and here's a significant quirk: as long as the USB is connected at the source (my laptop), the SPDI/F (Coaxial and Optical) Inputs will NOT play. To play SPDI/F you will have to unplug the USB cable. There is a small switch on the back that selects between Coaxial and Optical. As seen in the pic below, it uses 2x TDA-1305. Output level seems quite normal to me - not high, not low.. (I'd say around 2V). This is a sweet sounding DAC, just as I'd expect from this chip (as in my Micromega Stage 2). With the Wanptek SMPS, it actually is quite resolved while retaining its sweet quality. Before I forget, I did briefly tested its headphone output with my Grado SR-80e and it was good (of course you can only control the volume from the player). Very good job and one of my best purchases! See, I have bought several preamps and amps but getting another DAC rarely crossed my mind!

And, so! that's what's been happening. Keep checking once in a while, there are more articles to come...