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Posted by N-set on
11-07-2026
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I'm separating the thread on my latest baby - a twin 1541A NOS DAC here not to contaminate the thread on the expensive DAC's. The original post:
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=2&postID=29828#29828
 Paul S wrote: | | Jarek, do I see bypass caps in your PS box? Did you listen without the bypass caps before adding them? |
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Paul, there is no bypassing in the PS box but I used extensive bypassing of power supply caps in the signal box. AI has greatly helped me with designing those bypassing strategies and they are consistent with what e.g. Thorsten Loesch and other experienced builders advocates. Having said that, out of 8 supply lines, 7 end up with TentLabs shunts, the only line without them is the digital supply of the 8414 receiver. I did not have the nerve to listen to all bypassing additions and simply assumed a good engineering, accumulated diy experience, and more importantly the high quality shunt, shunting all that cap orgy will work. A guiding light has been this by now famous design:
https://www.mvaudiolabs.com/digital/tda1541a-reference-dac/
Having said that, the only place I indeed tested bypassing was at the 1541A's pins after the shunts. As I wrote earlier, the shunts+ bypasses produced at some point down the I/V resistor value optimization a very particular, highly holographic sound. there was a certain magic to it. But it was also "too much" of the holography in a sense that it was leaning towards boominess, like from a tunnel. After some hesitation, I removed the bypasses, the sound actually became a bit more alive although less 3D, and now 1541A's pins are fed directly by the tenlabs, placed only 1cm away. Leter, Lampizator's chief designer, a charming and very friendly guy, told me the boominess is sometimes caused by fresh elcaps, not burned in enough 9mine were off the shelf).
Another bypass I listened was at the 801A stage output cap. I bypassed Mifles 0.22uF plastics (recommended by Lampizator himself) by Duelund silver foil 0.01uF, I had left from a Tannoy crossover experiments where they did not work. They worked nicely, making the sound more sparkling and adding some detail (both very good for my system). All those tests were made using Stax Lambda Pro + SRM717 fed by Philips 304MkII and a selection of CD's including Baroque compilation by Alpha with Eva Zaichik and fragments of Guilini's B9.
All that diying wa s abig effort and I want to rest now, so my plan is:
1) Listen to the DAC for some months, it does produce a very pleasant sound, just not spectacular as I expected. See what happens after 20-50-100h hours.
2) Get a better transport, maybe there is the catch? I'm using Sony 557ESD in the main system with tentalbs clock but after some AI aided searching would like to try CEC TL1X with Lampizator/TentLabs mods of the SPDIF outputs.
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Posted by Paul S on
11-08-2026
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Even starting with stock gear one has to break it in (whatever that takes) and let it warm up and stabilize each session (however long that takes). Then, there are cords and cables to consider, along with the quality of connectors and connections, not to mention the AC. At some point, the active consideration of the gear, itself becomes too much for relaxed, attentive listening to Music. As it happens, the only bypass caps I use in my system are for phono stage couplers. Like the Miller effect, or inductive caps, there are almost always "other considerations" in active/reactive/working (vs. static/designed) electrical circuits. Plate curves are a great visual example of this, or a maybe a waterfall plot from a compression driver. The CEC transports sound pretty good if their belts are OK, so they are obviously doing something right, and the Sanyo guts are presumed to be good enough. I listen attentively when clocks come under discussion, but I really don't have a clear idea of how they work from digital input through analog output. Do we need more than one, and how do we keep it to one? My own DAC uses a (tiny) switching PS. Some years ago, a telecommunications engineer (John Rankin) opined at GSC that a properly-done SMPS was the quietest, most reliable way to provide lower voltages in audio gain paths, and I still have the stuff he sent to me so I could prove it to myself. I can easily hold it all (PCBs included) in the palm of one hand. Reactive values are literally forces to be reckoned with, along with "electrical/electronic byproducts" generated by activated parts and clusters of parts. A little Mu metal can go a long way. Another trick I learned was resistors soldered as straight extensions of tube pins, as opposed to right angles, to fit in the chassis. I think we have to somehow clean out the attic before we can really listen to Music. I used to meditate regularly; now it takes a while to get my brain up and running.
Paul S
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