In my opinion the VOCM mod makes the biggest improvement over all other mods. The C704 doesn’t change much with the XS4400.
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@gb-70 I checked your track at my volume 95, everything is fine, no artifacts were found. Even such a bass monster sounds without problems: RE: ECM by Ricardo Villalobos on TIDAL
P.S. The system has an “SVS 3000 micro” subwoofer.
And yes, there is an important feature in my mod, I have replaced AD8132 with AD8139.
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I checked my DS that has the LL1948 and found no issues with the tracks you used. It might have something to do with your preamp??? I tested it with two different Audio Research preamps.
I have 5 subwoofers so I would hear and see it if it were audible.
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Thank you @jkrichards , @yuriy and @tedsmith for your help and recommendations. This is all strange indeed. I will do the VOCM mod again and stay with the Edcor´s. They sound wonderful.
Yes. The Edcor’s sound pretty good in series secondary mode.
I rewired my Edcor transformers yesterday to better match the volume from my Stellar phono. What a difference.
Definitely worth the effort and no additional cost. The Edcors sound exceptionally good in series.
Thank you for this tip.
Cheers
Yes… Not bad for the price. It’s no LL1948 or better yet the Jensen JT-11SSP-8MA however worth the rework.
It’s not your preamp. I have the same effect with the track you mentioned and the Lundahl. I just still have the VOCM cap missing, installed next year.
The bass clipping stops somewhere down between 83 and 90 DS level, I have to find out exactly where later as my wife kills me if I play this bass part any longer 
. Means with the Lundahl‘s in parallel mode we again lose the gained gain.
I wonder if Ted has a further idea what it could be. It seems to be no soldering mistake or so but an incompatibility of the Lundahl‘s at a certain level of internal DS volume.
Wow, that is a kind of relief for me. But frustrating anyhow. Because the Lundahls were not cheap at all. I returned to the Edcor‘s, so no more troubleshooting possible on my side. What may be different on @jkrichards DS and yours (or mine)?
Mine is a very early upgrade kit from the PWD and it runs Sunlight. I would be happy to provide any other information necessary to resolve this mystery. Any idea from @tedsmith ?
Mine is no upgrade from the PWD but a regular version and also running on Sunlight.
I have no general problem to run the Lundahl’s at below 90 internal volume, so no reason for me to go back to Edcor, but anyway it would be interesting to solve the mystery why all that, especially if there are folks around which have no problem with that test track over 90 and the Lundahl’s. @jkrichards, really not?
I’m trying to catch-up on mods, and only have edcor and external LPS for for analog. If anybody has a few links for known good parts for VOCM, improved transformers, etc. I will appreciate it and pay it forward here. TIA!
Nether of my DS do what you described. It could be an incompatibility with grounding of the case/shield on the LL1948 as the XS 4400 do not ground the case / shield. Some preamps may not like this. My Audio Research preamps are true balanced (two amps of opposite polarities) and work perfect at all levels.
You can check this by cutting the trace on the adapter board that goes to pin 8 on the LL1948. We were going to add this solder ball to the adapter boards however at the time didn’t see it as an issue.
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My preamp is also truely balanced and if there’s no other way to find out I don’t really want to try the cut in case afterwards this can mean other problems….but if that’s the only relevant difference of the transformers…
I’d also have another preamp at hand which I could try at a later time…or headphones if the bass is obvious there.
It sounds like DC is passing through your preamp. Out test we did does not show any issues. When we get time we will run another test starting a DC and up.
It can be put back if needed. Just scrape off the coating on the board near the cut traces and put on a solder ball.
That‘s so cool. Elaborate and objective reply as usual. I really appreciate this.
I‘m afraid I opened another box of Pandora, oh boy…journey never ends.
That’s what modding is all about 
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I don’t think grounding the case on the LL1948 is necessary in this application as it’s being used as an output device instead of an input device as it was designed.
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Thanks for caring!! I’ll try in January unless there are new insights til then. Skiing soon
Can’t have to do with the external PSU used, right? As that’s another difference between units. I could switch back to the internal for testing.
No. I don’t think that the external power supply has anything to do with this.
Logically the only real obvious difference between the two transformers (besides sound quality) is the grounding of the transformer case. The original design and the new DS MKII doesn’t ground the case on the transformers.
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