The Bridge is fairly well grounded and ground shielded. I’m not suggesting that you miss out on the convenience of a streamer, but you might consider an external streamer. I’m not sure if PS Audio’s external streamer is near release, but people have strong opinions about many good quality streamers out there.
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You are correct that quad rate processing lowers the noise in the lower ultrasonic range and hence may not require quite as much lower frequency filtering. The 3dB knee of the current transformer is in the 50k to 80k region. The high end Jensen transformers are more like 220kHz. Quad rate processing keeps the DSD noise lower than the noise floor of the rest of the DAC to about 100k or 110kHz. So the Jensen transformer can allow noise between around 100k to 220k to be up to about 12dB louder.
The bass will definitely be extended by the Jensen transformers.
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Thanks so much for the information, Ted. The extended bass response would be welcomed. I’ll get right on this as soon as I complete my transformer-shrinkage machine.
Thank you Ted. Especially for reading all of that!
So I was partially correct in my assumption.
See, speed-racer I am not such an idiot after all.
You know what is funny? A long time ago we used to know Jensen as cheap car audio products. We also back then knew them as top quality audio transformers as well. mainly then used in pro audio products. today often found in the finest microphones ETC. Is this the same company that I speak of? does anyone know? I understand that Ted is using them in the TSS? i would like one in my DSS. Ted, could you in a somewhat abbreviated manner explain to me what this would entail? thank you
There are repeated descriptions about the problems with this idea on this thread. The most pragmatic problem is that there isn’t enough space.
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Okay. I am actually glad it cannot be done because I would rather not mess with it lol!
However There is a guy kind of like you nearby that most likely could jam it in there somehow but I don’t really want to even pay for it either. I doubt it makes a huge difference but rather a subtle one I am guessing. I am not speaking for him that he absolutely could do it. If there was any way possible whatsoever this guy would most likely figure it out however. I am guessing what he would do is just design a whole new board. Which is exactly why I do not wish to pay for it 
If it were to turn it into a DAC of a different league, perhaps but I highly doubt that this is to be the case. From a power input transformer alone. In fact, doesn’t it have a toroid? Or are we speaking of different transformers here? I thought we were speaking of the power inlet and not the audio transformer. Yes, I would imagine the audio transformer being a large difference in size. Anyways, the Jensen may be somewhat better but I doubt that you put a junk transformer in there to begin with? I think you have mentioned this already, so you really do not need to again.
Sure, with the caveat that I am NOT encouraging anyone to do any of these mods and, if they do, it is their responsibility alone. (I have touched on some mods in the past and then worried that someone will think they are easier than they sound and would end up wasting their DS or worse … and, remember, death is permanent.)
(Also, to preempt potential flames, part of my enjoyment in this hobby is building and modifying equipment to suit my personal philosophies, so please take that into consideration.)
The following includes only those that made a positive improvements to my ears in my system, and are the result of many hours and extensive testing/listening:
Shielding mods:
- All cables and ribbons between boards were shielded with copper tape, then insulated, with one or both ends grounded to chassis. Shielding on the ribbon between the input and analog boards is lifted away from the ribbon to minimize the effects on its characteristic impedance, which I am rather certain Ted compensated for. I don’t have a Bridge, so I didn’t do this between the power supply and input boards.
- Copper shield behind the touchscreen display board. (While not close to a complete Faraday shield, I think this helped, although it was done at the same time as one power supply mod.)
Power supply mods:
- Feed DS with dedicated Topaz isolation transformer. (I expect PS Audio power supplies would be even better but, as my user name suggests, I’m drawn to simpler, passive changes where acceptable.)
- Bypassed the power switch, since I leave my DS on all the time.
- Replaced the analog board power supply with an internal supply using a split bobbin IE transformer and a Belleson regulator.
- Switched the 5v supply for the display board to come from a regulator that didn’t appear to be used in the DS (or was the one for the Bridge … I’ll have to look into my notes). This lightened the load on the regulator feeding the input board and reduced noise injected from the display to the input board … a lot. It requires cutting a trace and adding a jumper.
- Relaced the 5v regulator feeding the input board with a Belleson.
- The same regulator is now fed from the original 12 supply (regulator unused after mod 3), cascaded, with an RC filter between.
That’s all I can remember right now. Haven’t really touched the analog board other than to ad a little stick-on damping sheet material and modified the output transformer to double the single-ended output voltage. I have things I want to test in the future, but it sounds damn good to me as it is.
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That’s exactly what I’m doing. No Bridge and my Windows 10 PC is just a “remote controil” for Qobuz/Audirvana. When I play a track, DLNA kicks in and digital path switches over to my Sony’s I2S going into the DSSr.
Ted’s explanation tells you that that clocks in ovens are designed to be more stable over longer time periods. His explanation does not suggest that clocks in ovens last longer than clocks not in ovens which was you assumption. Well, that is what you wrote anyway…
The two regulators at the back are more difficult to access, and one is the 12v analog regulator if I recall correctly. Replacing any of the LM317Ts with Bellesons requires that a resistor in the original circuit is removed. Adding a whole new 12 volt supply from a dedicated transformer helps to isolate the analog board from digital supply noise.
The two regulators at the edge of the power board are easier to access and replace, one being the more important one that feeds the input board.
Hmmm. Assuming that they are already well regulated to the specified voltages, I’d say you then run the 12 volt supply directly to the analog board and tie the 5 volt supplies into appropriate spots on the power supply board, removing the existing transformer, regulators and rectifies as required.
For giggles I looked this up, and it’s not that expensive a part, although with a long lead time. So this is apparently a plug-in substitution for the stock item in the DS that potentially would sound better - or at least different?
I’m assuming that when you say " better" that was by comparison to the transformer that ended up in the final design, the decision being dictated by cost parameters.
With so much having been said about the critical role of transformers, the prospect of “transformer rolling” will surely appeal to some. 
I found Edcor when I was looking for quad filer wound transformers that were cheaper than the Jensen’s. I then noticed that Edcor had some other possible choices that, tho, not quad filer should work. Quad filter wound transformers have all windings wound the same so you can pick and choose which to parallel or put in series if you want (e.g. 1 for primary and 3 in parallel for secondary.)
I only needed two separate primaries and a center tapped output so I could use a transformer that didn’t cost extra for the quad filer style windings.
Still the 4400 transformers have better specs for more money and are pin compatible with the board layout so they could be worth a try.
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The Edcor is an attractive option, since it and the Jensen are both claimed to be -1dB at 10Hz, while the other end the Edcor and Jensen show -1dB at 50 or about 125kHz respectively. So the Edcor might be a better low pass filter and the core is made from trusty old M6.
Not that it matters but FWIW
I’m not quite sure which Jensen you are looking at but the low -1dB and -3dB are way lower than 10Hz:
JT-11SSP-8MA : -1dB 0.6Hz and approx. 120kHz -3dB 0.25Hz and 220kHz
JT-11SSP-7MPC : -1dB 1Hz and approx. 120kHz -3dB 0.4Hz and 200kHz
JT-11SSP-6M : -1dB 0.8Hz and approx. 150kHz -3dB 0.4Hz and 220kHz
I used the JT-11SSP-8MA in my pre PS Audio prototypes but it’s not listed at the Jensen site anymore.
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You are absolutely right, I was reading the scale for the JT-11SSP-7MPC graph incorrectly (-1 dB at 1 hz!). I’m pretty sure that would be highly audible.
I understand, the -3dB specs are at the top of the datasheet, but boy getting the -1dB specs took a lot of staring on my part.
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If you are going to have modders do the work, they probably have their favorite replacements for the regulators in the top level power supply. Many times modders use a more complicated circuit that’s designed to physically fit in the same space as the regulators they are replacing but have some noise canceling, filtering circuits. While you don’t need excellent regulators here, they do need to dissipate a lot of heat, I don’t know what the voltages are at the regulator’s inputs, so I don’t know if the LT1764’s maximum input voltage is high enough…
There are certainly regulators with better specs. Instead of only replacing the regulators I’d consider whole quality supplies at one extreme to patching the current power supply at the other. For example replacing the bridge diodes and using some bypass caps for the main caps (and perhaps snubbers on the bridge diodes). I’ve covered this in earlier posts on this thread.
Also I should remind people that there are some modders out there that just advertise mods to the DS but they are the same mod package they do to other DACs, I spent time earlier in this thread mentioning many standard mods that are just not appropriate to the DS and some will hurt performance: I’d stay away from modders that mention things like “silver wire” (where is that a good idea in the DS? Did they even open the box before they mention it?) I’d also stay away from modders that don’t have good surface mount rework stations, there are caps on the DS that can’t take the heat of a soldering iron without severe degradation that affects the sound quality.
I’ve been purposefully vague at times just to give inspiration to those who can do mods safely but not specific enough information to encourage those that can’t.
I think I’m going to quit now. To be blunt I’m not going to design specific mods, modders should be able to make decisions like these themselves or find people that can and if you need to ask questions this specific you shouldn’t be modding. People aren’t reading what I already posted so I’m not going to keep saying the same things over and over.
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Ted, do the things talked about here make a night and day difference? Or would the money be better spent towards a better DAC such as the TSS? Since if someone does the work and does all of it, it can be quite costly. Would the cost perhaps outweigh the benefits? Lets say for instance it cost more than 60% of the price of the DSS. Would that be a wise investment in your opinion? I mean would the sound be improved to the level of a completely different class of DAC from the mods mentioned herein?
Also could you please clarify. Did you not also say that ovens allow clocks to maintain consistent performance over years of use? Or did I misunderstand you?
Thank you Ted
Crystal ovens maintain a more constant temperature which helps the stability of the crystal. I.e. the drift of the crystal may be taken from, say 10 ppm / year to 1 ppm / year. (Or similarly over any other time period.) They don’t affect short term phase noise as much since it takes a while for the temperature to change.
Changing the 12V supply will probably get a result like Redcloud to Windom. The other changes are probably smaller. But if many are done they will add up to something like a good cable change (or two.)
I don’t bother with my DS because I can usually make a bigger difference with software. Some of the changes people have done don’t affect the DS as much with current software as much as they might have with older software.
These kind of mods will never take a DS to the level of the TSS, and probably not to the level of a theoretical DS replacement, but the differences are available now and different DACs from PS Audio aren’t (yet.)
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