[mgalusha]

After all the info in the Felix xxx threads and some email from Paul last summer I figured it was time to play with a few of these. A quick order to Coilcraft (shipped same day) and Mouser for some X2 caps and I was in business.

I was able to squeeze this into a DCX though I had to move the PSU over a little to make room.



I'm very pleased with the results. I was able to compare this with another DCX that has the same mods and the addition of the Felix conditioner provided a quieter background and more realistic sounding music. Highs had more delicacy but with proper bite on things like trumpet. Vocals seemed to take on more body, less like a recording. Bass doesn't seem as pronounced but does seem more natural, which is a trade off I'll accept.

Thanks to Paul, Gary, Josh and others who've contributed to this project. For less than $20 this is pretty much a no brainer if you can _safely_ put this in your gear.

Mike

[tanchiro58]

I'm very pleased with the results. I was able to compare this with another DCX that has the same mods and the addition of the Felix conditioner provided a quieter background and more realistic sounding music. Highs had more delicacy but with proper bite on things like trumpet. Vocals seemed to take on more body, less like a recording. Bass doesn't seem as pronounced but does seem more natural, which is a trade off I'll accept.

Mike,

I got the same results with my SB3. I could hear some more details I missed before. It is so clean (but not like those PCs). Therefore, I will build some more Felix conditioner for my other sources in my system. Very nice work! 

Tan

[JDUBS]

As usual, very nice job, Mike!!

-Jim 

[JoshK]

Very cool Mike.  Does the DCX have a switcher?  Looks like it and it would make sense, but I don't know if you replaced it with a linear.

[Occam]

Mike,

Very slick!
With those tight quarters, I guess you didn't have room for bypass caps, even on the output side.

I'll point out to others that the DCX already has a C-CMC-C (basically a mini-Felix), as do almost all switching supplies, already on the mains input. But these puny efforts, sadly, are there typically not for reduced noise on its output, but to meet FCC and other countries regulators standards for noise coming out of the supply into the mains. Fortunately, the macho Felix minimizes noise at both the input and output.

Thanks again for sharing your projects,

Paul

[mgalusha]

Very cool Mike.  Does the DCX have a switcher?  Looks like it and it would make sense, but I don't know if you replaced it with a linear.

Josh,

It is a switcher and I did try replacing it with a linear, in particular the one from www.awdiy.com. Completely against my expectations it sounded much better with the switcher. I let the linear PS run in for 5 days and it I just didn't want to listen to music with that PS. Note that the new SRC/Clock/Receiver board has some very good low noise regulators on board and I replaced both of the 7805's on the main board with two of these same regs, designed by Frank Oettle in Germany. I think perhaps these regs have such a high PSRR that they are taking care of any noise from the switcher, or at least enough that the switching PS's power delivery outweighs any potential noise.

If you look in the photo you can see two small chokes in the power wires from the PS to the board. These were also suggested by Frank along with changing two of the caps on the board to form an LC filter. These are on the +/- 15V lines feeding the analog board, which has additional regulators as well.

[mgalusha]

Very slick!
With those tight quarters, I guess you didn't have room for bypass caps, even on the output side.

They are there Paul, just hard to see. They are tucked in under the edges of the CMC, you can just see the end of one peeking out on the right side.

The .01/.1uF Vishay caps were just the right size to fit under the CMC. I'm going to build another one today, I'll take a picture of where I stuck the caps.

Again, thanks for the ideas. BTW, the little perf board from Radio Shack are exactly the right size for this project. I didn't have to cut anything, just enlarge 4 holes for the CMC.

[jhm731]

Mike-

Nice work.

Why not get rid of the "puny" line filter on SMPS board and wire the Felix in it's place instead of running them in series.

I'd recommend upgrading the SIP bridge, here's an ultra fast recovery SIP bridge I used in my TacT PSU:



I have couple extras if you're interested in trying one.

I'd also recommend upgrading the large cap (probably 100-150uf) after the SIP Bridge to a BG Power Tank or a Jensen 4-pole, if it will fit.

[mgalusha]

Why not get rid of the "puny" line filter on SMPS board and wire the Felix in it's place instead of running them in series.

I'd recommend upgrading the SIP bridge, here's an ultra fast recovery SIP bridge I used in my TacT PSU:

I have couple extras if you're interested in trying one.

I'd also recommend upgrading the large cap (probably 100-150uf) after the SIP Bridge to a BG Power Tank or a Jensen 4-pole, if it will fit.

I thought about bypassing the existing filter but I've learned to do things one step at a time, I like to be sure I know what each thing is doing.

I have thought about a Jensen 4 pole but space is very limited, the DCX is only 1U high. I might be able to squeeze one between the front panel and the PS. Have to measure and see. Of course then there is lead inductance to consider, no free lunch.

I've love to try one of the fast bridges if you have a spare. If not, I need to place a Mouser or DigiKey order soon anyway.