Modding the DirectStream DAC

I don’t have a Farad but HDPLEX300. The easiest thing to do is have the DS and the LPS switched on together with same switch or a regenerator like a P20, P15, P10 or P3. Otherwise you can end up with no sound or noise feeding through. Booted exactly together no issue

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Not so with the Farad, as its delay causes it to provide the power then after the digital board is online, which means the muted sound for a while as Ted mentioned.

This would mean the same as powering on simultaneously (muted sound for a while).

These XS 4400 transformers are the same as the
API and Ed Anderson EA2503 Vintage API Clone Output Transformer except for the PC board mounting.

Interesting these same transformers are used in Professional mixing consoles and outboard gear by API and others. Lots of music has been made using API gear. Good stuff! Les Paul used these in his console in the late 60’s / 70’s. These transformers are usually driven with the the famous API 2520 discrete opamp. I use the API 512c Discrete Mic / Line Pre every day in the studio. It uses both the 2520 and this type of Quadfiler 1:1:1:1 matching transformer. No wonder it makes the DS sing.


I ordered my transformers 9-13 Monday. Tracking states I will have them on Sunday 9-19. Edcor is shipping these things out fast. Warming up my rework gear. :smile:

Transformers are installed. Easy job with the hakko FR-301. Received the PW DSD last Sunday. Finished transformer install Today. First impressions… A giant leap in the sound I was hoping for. Larger clearer staging. Thanks everyone here who encouraged this mod.


Just checked out the de soldering tool you used.
A little pricey, but I’m sure it makes the task at hand much easier.

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Yes it does. I use it all the time. It took about 3 minutes to de-solder and remove both transformers without damaging the old ones.

I’m going to burn it in until next weekend then I will have my son run it through the AP to see what these transformers do on paper.

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That is quite the desoldering tool. I assume with it there was no need to cut the transformer legs on the installed unit.

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Did not need to cut the original transformers legs. The original transformer can be reinstalled if one wants to do so.

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Great to know. It is on the que for me to do. Got a lot of irons in the fire at the moment.

I just realized after reading about shielding behind the display screen that my unit has none. Does anyone else have a missing shield? Seems this is a source for noise.

Yours looks like they all do from factory. Adding shield everywhere Ted suggests is very beneficial as is covering/encasing the output transformers to shield susceptibility to EMI and RF. The additional shielding and external LPS was as big or bigger improvement than just replacing the transformers to my ears.

I see shielding in many photos and videos. Is this something that was deleted? Mine was made in 2014.

Here is what I’m talking about. Is this available to purchase?

Yes…or more important …especially after the transformer mod.

Well mine looked like yours prior to adding 3M shielding essentially erecting a similar wall with the 3M Sheets and covering the noisy emitting RF components.

Min is a 2018 manufactured model.

Has it been definitively determined which 3M shielding is the right one to use? There’s more than one. I’m guessing they are all meant for slightly different applications.

It would probably be best to install 4 - 4-40 X 1 standoffs and a RF shielding plate.