I don’t recommend the XS4400 1:2 mod. The high frequency roll off is not good. Down over 1dB at 20khz. Also the phase error is not good.
It doesn’t have a temp readout just an adjustment dial in the handle. I have some old circuit boards that I use for practice, especially getting temps correct. Like Jeff, ended up at 2.5 on the dial. If I were to guess it’s around 800F. At that setting solder melts fast enough where I am not worried about applying heat too long before I pull the trigger. Really just a few seconds.
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Thank you both for the responses. Based on Jeff’s response, I won’t do the 4400 1:2 mod. Instead, I’ll continue to save my pennies for a pair of Jeff’s transformers. In the meantime, I’ll continue to enjoy my modded DS1, which sounds so much better than the stock version. I’ll deal with my trusty ZD-915 (at 425C) when I purchase the new transformers 
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I used 400C to remove the XS4400s and it was plenty hot enough for the Oyaide 4.7% Silver Solder I used to install them.
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Pins 8 and 11 need a bit more heat than 400c.
Been doing a ton of them lately.
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Hello Richards, I’m buying the caps you indicated for the VOCM mod, but I bumped into these 2 options, I didn’t understand if it refers to the type of caps, which one should I choose?
Thanks!
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They are the same however I don’t think you want a reel.
Just get the cut tape.
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More info can also be seen here: Audiogon Discussion Forum
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Hi guys, I upgraded MkI LL1984 transformers, C704=8.2nF, R5/6 500Ohm replaced tiny film and 47uF Nichicon VOCM bypass, 12V external power supply. I stopped reading this endless thread after this and I enjoy music like never before. I am lost in the number of posts now. Is there another important step that I missed?
Thanks
With 8.2nF you have the same as I chose…definitely no higher value and the next available lower 6.8nF was too hot on some recordings in my case…so perfect choice from my perspective.
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Lots new here
Hey guys, I’m planning to upgrade the 4400 Edcor to Jeff’s transformers, did anyone do this upgrade sequence? is it a consistent upgrade?
It’s where I’m at , I stoped modding after until I am confident that they took it to the max… I will be doing the JkRichards mods shortly.
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Yep. My first mod was the 4400’s. Then I added input shorting plugs. Most recently I did the APS transformers along with the Vocm capacitors and swapped R5 and R6 for thin films. That was a big change, very worthwhile. And I now have one of JK’s analog power supply boards coming to complete the set.
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I started with the analogue power supply board, then Edcor 4400, shorting plugs, VOCM and finally the APS transformers.
The last step was the greatest in quality improvements by a major level.
All together, they add up to an amazing sound. I don’t have any plans for more changes.
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If you haven’t heard 4400 with a GOOD power supply unit (PSU), then you haven’t heard their full potential.
With GOOD PSU (not cheap Chinese stuff), the sound improvement from 4400 without PSU → to → 4400 with PSU was much bigger than 4400 w/PSU → APS transformers w/PSU AND VOCM MOD.
I can’t say anything about sound improvements when 4400 swapped with APS WITHOUT PSU mod
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Thanks everyone for the comments, I already use a good external source for the analog board, and today I left the dac to make the VOCM mod, in the sequence I must acquire the nickel transformers, I prefer to do it this way, step by step to feel the weight of every upgrade.
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This is the right way to go! Shame on me, I haven’t done the Vocm mod before I swapped the 4400 with APS transformers… I wish I could discern the Vcom mod impact on the sound… and report here.
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First hours with the Vocm mod, what bass 
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Off topic, but I ordered JK’s new transformers for the MKII and was wondering if there was anyone in the New York/Tri state area that would have the skill to install them for me? I’m not skilled enough to do it myself and hoping to not have to ship my MKII to JK. Plus you’d get to hear the MKII! PM me if possible.